4 This directory contains Device Tree overlays. Device Tree makes it possible
5 to support many hardware configurations with a single kernel and without the
6 need to explicitly load or blacklist kernel modules. Note that this isn't a
7 "pure" Device Tree configuration (c.f. MACH_BCM2835) - some on-board devices
8 are still configured by the board support code, but the intention is to
9 eventually reach that goal.
11 On Raspberry Pi, Device Tree usage is controlled from /boot/config.txt. By
12 default, the Raspberry Pi kernel boots with device tree enabled. You can
13 completely disable DT usage (for now) by adding:
17 to your config.txt, which should cause your Pi to revert to the old way of
18 doing things after a reboot.
20 In /boot you will find a .dtb for each base platform. This describes the
21 hardware that is part of the Raspberry Pi board. The loader (start.elf and its
22 siblings) selects the .dtb file appropriate for the platform by name, and reads
23 it into memory. At this point, all of the optional interfaces (i2c, i2s, spi)
24 are disabled, but they can be enabled using Device Tree parameters:
26 dtparam=i2c=on,i2s=on,spi=on
28 However, this shouldn't be necessary in many use cases because loading an
29 overlay that requires one of those interfaces will cause it to be enabled
30 automatically, and it is advisable to only enable interfaces if they are
33 Configuring additional, optional hardware is done using Device Tree overlays
36 GPIO numbering uses the hardware pin numbering scheme (aka BCM scheme) and
37 not the physical pin numbers.
42 The Advanced Options section of the raspi-config utility can enable and disable
43 Device Tree use, as well as toggling the I2C and SPI interfaces. Note that it
44 is possible to both enable an interface and blacklist the driver, if for some
45 reason you should want to defer the loading.
50 As well as describing the hardware, Device Tree also gives enough information
51 to allow suitable driver modules to be located and loaded, with the corollary
52 that unneeded modules are not loaded. As a result it should be possible to
53 remove lines from /etc/modules, and /etc/modprobe.d/raspi-blacklist.conf can
54 have its contents deleted (or commented out).
59 Overlays are loaded using the "dtoverlay" config.txt setting. As an example,
60 consider I2C Real Time Clock drivers. In the pre-DT world these would be loaded
61 by writing a magic string comprising a device identifier and an I2C address to
62 a special file in /sys/class/i2c-adapter, having first loaded the driver for
63 the I2C interface and the RTC device - something like this:
67 echo ds1307 0x68 > /sys/class/i2c-adapter/i2c-1/new_device
69 With DT enabled, this becomes a line in config.txt:
71 dtoverlay=i2c-rtc,ds1307
73 This causes the file /boot/overlays/i2c-rtc.dtbo to be loaded and a "node"
74 describing the DS1307 I2C device to be added to the Device Tree for the Pi. By
75 default it usees address 0x68, but this can be modified with an additional DT
78 dtoverlay=i2c-rtc,ds1307,addr=0x68
80 Parameters usually have default values, although certain parameters are
81 mandatory. See the list of overlays below for a description of the parameters
84 Making new Overlays based on existing Overlays
85 ==============================================
87 Recent overlays have been designed in a more general way, so that they can be
88 adapted to hardware by changing their parameters. When you have additional
89 hardware with more than one device of a kind, you end up using the same overlay
90 multiple times with other parameters, e.g.
92 # 2 CAN FD interfaces on spi but with different pins
93 dtoverlay=mcp251xfd,spi0-0,interrupt=25
94 dtoverlay=mcp251xfd,spi0-1,interrupt=24
96 # a realtime clock on i2c
97 dtoverlay=i2c-rtc,pcf85063
99 While this approach does work, it requires knowledge about the hardware design.
100 It is more feasible to simplify things for the end user by providing a single
101 overlay as it is done the traditional way.
103 A new overlay can be generated by using ovmerge utility.
104 https://github.com/raspberrypi/utils/blob/master/ovmerge/ovmerge
106 To generate an overlay for the above configuration we pass the configuration
107 to ovmerge and add the -c flag.
109 ovmerge -c mcp251xfd-overlay.dts,spi0-0,interrupt=25 \
110 mcp251xfd-overlay.dts,spi0-1,interrupt=24 \
111 i2c-rtc-overlay.dts,pcf85063 \
112 >> merged-overlay.dts
114 The -c option writes the command above as a comment into the overlay as
115 a marker that this overlay is generated and how it was generated.
116 After compiling the overlay it can be loaded in a single line.
120 It does the same as the original configuration but without parameters.
122 The Overlay and Parameter Reference
123 ===================================
125 N.B. When editing this file, please preserve the indentation levels to make it
126 simple to parse programmatically. NO HARD TABS.
130 Info: Configures the base Raspberry Pi hardware
131 Load: <loaded automatically>
133 ant1 Select antenna 1 (default). CM4 only.
135 ant2 Select antenna 2. CM4 only.
137 noant Disable both antennas. CM4 only.
139 audio Set to "on" to enable the onboard ALSA audio
140 interface (default "off")
142 axiperf Set to "on" to enable the AXI bus performance
144 See /sys/kernel/debug/raspberrypi_axi_monitor
147 cam0_reg Enables CAM 0 regulator. CM1 & 3 only.
149 cam0_reg_gpio Set GPIO for CAM 0 regulator. Default 30.
152 cam1_reg Enables CAM 1 regulator. CM1 & 3 only.
154 cam1_reg_gpio Set GPIO for CAM 1 regulator. Default 2.
157 eee Enable Energy Efficient Ethernet support for
158 compatible devices (default "on"). See also
159 "tx_lpi_timer". Pi3B+ only.
161 eth_downshift_after Set the number of auto-negotiation failures
162 after which the 1000Mbps modes are disabled.
163 Legal values are 2, 3, 4, 5 and 0, where
164 0 means never downshift (default 2). Pi3B+ only.
166 eth_led0 Set mode of LED0 - amber on Pi3B+ (default "1"),
167 green on Pi4 (default "0").
168 The legal values are:
172 0=link/activity 1=link1000/activity
173 2=link100/activity 3=link10/activity
174 4=link100/1000/activity 5=link10/1000/activity
175 6=link10/100/activity 14=off 15=on
179 0=Speed/Activity 1=Speed
180 2=Flash activity 3=FDX
185 eth_led1 Set mode of LED1 - green on Pi3B+ (default "6"),
186 amber on Pi4 (default "8"). See eth_led0 for
189 eth_max_speed Set the maximum speed a link is allowed
190 to negotiate. Legal values are 10, 100 and
191 1000 (default 1000). Pi3B+ only.
193 i2c_arm Set to "on" to enable the ARM's i2c interface
196 i2c_vc Set to "on" to enable the i2c interface
197 usually reserved for the VideoCore processor
200 i2c An alias for i2c_arm
202 i2c_arm_baudrate Set the baudrate of the ARM's i2c interface
205 i2c_vc_baudrate Set the baudrate of the VideoCore i2c interface
208 i2c_baudrate An alias for i2c_arm_baudrate
210 i2s Set to "on" to enable the i2s interface
213 krnbt Set to "on" to enable autoprobing of Bluetooth
214 driver without need of hciattach/btattach
217 krnbt_baudrate Set the baudrate of the PL011 UART when used
220 spi Set to "on" to enable the spi interfaces
223 spi_dma4 Use to enable 40-bit DMA on spi interfaces
224 (the assigned value doesn't matter)
227 random Set to "on" to enable the hardware random
228 number generator (default "on")
230 sd_overclock Clock (in MHz) to use when the MMC framework
233 sd_poll_once Looks for a card once after booting. Useful
234 for network booting scenarios to avoid the
235 overhead of continuous polling. N.B. Using
236 this option restricts the system to using a
237 single card per boot (or none at all).
240 sd_force_pio Disable DMA support for SD driver (default off)
242 sd_pio_limit Number of blocks above which to use DMA for
245 sd_debug Enable debug output from SD driver (default off)
247 sdio_overclock Clock (in MHz) to use when the MMC framework
248 requests 50MHz for the SDIO/WLAN interface.
250 tx_lpi_timer Set the delay in microseconds between going idle
251 and entering the low power state (default 600).
252 Requires EEE to be enabled - see "eee".
254 uart0 Set to "off" to disable uart0 (default "on")
256 uart1 Set to "on" or "off" to enable or disable uart1
259 watchdog Set to "on" to enable the hardware watchdog
262 act_led_trigger Choose which activity the LED tracks.
263 Use "heartbeat" for a nice load indicator.
266 act_led_activelow Set to "on" to invert the sense of the LED
268 N.B. For Pi 3B, 3B+, 3A+ and 4B, use the act-led
271 act_led_gpio Set which GPIO to use for the activity LED
272 (in case you want to connect it to an external
274 (default "16" on a non-Plus board, "47" on a
276 N.B. For Pi 3B, 3B+, 3A+ and 4B, use the act-led
282 As for act_led_*, but using the PWR LED.
283 Not available on Model A/B boards.
285 N.B. It is recommended to only enable those interfaces that are needed.
286 Leaving all interfaces enabled can lead to unwanted behaviour (i2c_vc
287 interfering with Pi Camera, I2S and SPI hogging GPIO pins, etc.)
288 Note also that i2c, i2c_arm and i2c_vc are aliases for the physical
289 interfaces i2c0 and i2c1. Use of the numeric variants is still possible
290 but deprecated because the ARM/VC assignments differ between board
291 revisions. The same board-specific mapping applies to i2c_baudrate,
292 and the other i2c baudrate parameters.
296 Info: Pi 3B, 3B+, 3A+ and 4B use a GPIO expander to drive the LEDs which can
297 only be accessed from the VPU. There is a special driver for this with a
298 separate DT node, which has the unfortunate consequence of breaking the
299 act_led_gpio and act_led_activelow dtparams.
300 This overlay changes the GPIO controller back to the standard one and
301 restores the dtparams.
302 Load: dtoverlay=act-led,<param>=<val>
303 Params: activelow Set to "on" to invert the sense of the LED
306 gpio Set which GPIO to use for the activity LED
307 (in case you want to connect it to an external
312 Name: adafruit-st7735r
313 Info: Overlay for the SPI-connected Adafruit 1.8" 160x128 or 128x128 displays,
314 based on the ST7735R chip.
315 This overlay uses the newer DRM/KMS "Tiny" driver.
316 Load: dtoverlay=adafruit-st7735r,<param>=<val>
317 Params: 128x128 Select the 128x128 driver (default 160x128)
318 rotate Display rotation {0,90,180,270} (default 90)
319 speed SPI bus speed in Hz (default 4000000)
320 dc_pin GPIO pin for D/C (default 24)
321 reset_pin GPIO pin for RESET (default 25)
322 led_pin GPIO used to control backlight (default 18)
326 Info: Overlay for the SPI-connected Adafruit 1.8" display (based on the
327 ST7735R chip). It includes support for the "green tab" version.
328 This overlay uses the older fbtft driver.
329 Load: dtoverlay=adafruit18,<param>=<val>
330 Params: green Use the adafruit18_green variant.
331 rotate Display rotation {0,90,180,270}
332 speed SPI bus speed in Hz (default 4000000)
333 fps Display frame rate in Hz
334 bgr Enable BGR mode (default off)
335 debug Debug output level {0-7}
336 dc_pin GPIO pin for D/C (default 24)
337 reset_pin GPIO pin for RESET (default 25)
338 led_pin GPIO used to control backlight (default 18)
342 Info: Overlay for activation of ADAU1977 ADC codec over I2C for control
344 Load: dtoverlay=adau1977-adc
348 Name: adau7002-simple
349 Info: Overlay for the activation of ADAU7002 stereo PDM to I2S converter.
350 Load: dtoverlay=adau7002-simple,<param>=<val>
351 Params: card-name Override the default, "adau7002", card name.
355 Info: Overlay for activation of Texas Instruments ADS1015 ADC over I2C
356 Load: dtoverlay=ads1015,<param>=<val>
357 Params: addr I2C bus address of device. Set based on how the
358 addr pin is wired. (default=0x48 assumes addr
360 cha_enable Enable virtual channel a. (default=true)
361 cha_cfg Set the configuration for virtual channel a.
362 (default=4 configures this channel for the
363 voltage at A0 with respect to GND)
364 cha_datarate Set the datarate (samples/sec) for this channel.
365 (default=4 sets 1600 sps)
366 cha_gain Set the gain of the Programmable Gain
367 Amplifier for this channel. (default=2 sets the
368 full scale of the channel to 2.048 Volts)
370 Channel (ch) parameters can be set for each enabled channel.
371 A maximum of 4 channels can be enabled (letters a thru d).
372 For more information refer to the device datasheet at:
373 http://www.ti.com/lit/ds/symlink/ads1015.pdf
377 Info: Texas Instruments ADS1115 ADC
378 Load: dtoverlay=ads1115,<param>[=<val>]
379 Params: addr I2C bus address of device. Set based on how the
380 addr pin is wired. (default=0x48 assumes addr
382 cha_enable Enable virtual channel a.
383 cha_cfg Set the configuration for virtual channel a.
384 (default=4 configures this channel for the
385 voltage at A0 with respect to GND)
386 cha_datarate Set the datarate (samples/sec) for this channel.
387 (default=7 sets 860 sps)
388 cha_gain Set the gain of the Programmable Gain
389 Amplifier for this channel. (Default 1 sets the
390 full scale of the channel to 4.096 Volts)
392 Channel parameters can be set for each enabled channel.
393 A maximum of 4 channels can be enabled (letters a thru d).
394 For more information refer to the device datasheet at:
395 http://www.ti.com/lit/ds/symlink/ads1115.pdf
399 Info: ADS7846 Touch controller
400 Load: dtoverlay=ads7846,<param>=<val>
401 Params: cs SPI bus Chip Select (default 1)
402 speed SPI bus speed (default 2MHz, max 3.25MHz)
403 penirq GPIO used for PENIRQ. REQUIRED
404 penirq_pull Set GPIO pull (default 0=none, 2=pullup)
405 swapxy Swap x and y axis
406 xmin Minimum value on the X axis (default 0)
407 ymin Minimum value on the Y axis (default 0)
408 xmax Maximum value on the X axis (default 4095)
409 ymax Maximum value on the Y axis (default 4095)
410 pmin Minimum reported pressure value (default 0)
411 pmax Maximum reported pressure value (default 65535)
412 xohms Touchpanel sensitivity (X-plate resistance)
415 penirq is required and usually xohms (60-100) has to be set as well.
416 Apart from that, pmax (255) and swapxy are also common.
417 The rest of the calibration can be done with xinput-calibrator.
418 See: github.com/notro/fbtft/wiki/FBTFT-on-Raspian
419 Device Tree binding document:
420 www.kernel.org/doc/Documentation/devicetree/bindings/input/ads7846.txt
424 Info: Analog Devices ADV7282M analogue video to CSI2 bridge.
425 Uses Unicam1, which is the standard camera connector on most Pi
427 Load: dtoverlay=adv7282m,<param>=<val>
428 Params: addr Overrides the I2C address (default 0x21)
429 media-controller Configure use of Media Controller API for
430 configuring the sensor (default off)
434 Info: Analog Devices ADV728[0|1|2]-M analogue video to CSI2 bridges.
435 This is a wrapper for adv7282m, and defaults to ADV7282M.
436 Load: dtoverlay=adv728x-m,<param>=<val>
437 Params: addr Overrides the I2C address (default 0x21)
438 adv7280m Select ADV7280-M.
439 adv7281m Select ADV7281-M.
440 adv7281ma Select ADV7281-MA.
441 media-controller Configure use of Media Controller API for
442 configuring the sensor (default off)
445 Name: akkordion-iqdacplus
446 Info: Configures the Digital Dreamtime Akkordion Music Player (based on the
447 OEM IQAudIO DAC+ or DAC Zero module).
448 Load: dtoverlay=akkordion-iqdacplus,<param>=<val>
449 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
450 Digital volume control. Enable with
451 dtoverlay=akkordion-iqdacplus,24db_digital_gain
452 (The default behaviour is that the Digital
453 volume control is limited to a maximum of
454 0dB. ie. it can attenuate but not provide
455 gain. For most users, this will be desired
456 as it will prevent clipping. By appending
457 the 24db_digital_gain parameter, the Digital
458 volume control will allow up to 24dB of
459 gain. If this parameter is enabled, it is the
460 responsibility of the user to ensure that
461 the Digital volume control is set to a value
462 that does not result in clipping/distortion!)
465 Name: allo-boss-dac-pcm512x-audio
466 Info: Configures the Allo Boss DAC audio cards.
467 Load: dtoverlay=allo-boss-dac-pcm512x-audio,<param>
468 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
469 Digital volume control. Enable with
470 "dtoverlay=allo-boss-dac-pcm512x-audio,
472 (The default behaviour is that the Digital
473 volume control is limited to a maximum of
474 0dB. ie. it can attenuate but not provide
475 gain. For most users, this will be desired
476 as it will prevent clipping. By appending
477 the 24db_digital_gain parameter, the Digital
478 volume control will allow up to 24dB of
479 gain. If this parameter is enabled, it is the
480 responsibility of the user to ensure that
481 the Digital volume control is set to a value
482 that does not result in clipping/distortion!)
483 slave Force Boss DAC into slave mode, using Pi a
484 master for bit clock and frame clock. Enable
485 with "dtoverlay=allo-boss-dac-pcm512x-audio,
489 Name: allo-boss2-dac-audio
490 Info: Configures the Allo Boss2 DAC audio card
491 Load: dtoverlay=allo-boss2-dac-audio
496 Info: Configures the Allo Digione audio card
497 Load: dtoverlay=allo-digione
501 Name: allo-katana-dac-audio
502 Info: Configures the Allo Katana DAC audio card
503 Load: dtoverlay=allo-katana-dac-audio
507 Name: allo-piano-dac-pcm512x-audio
508 Info: Configures the Allo Piano DAC (2.0/2.1) audio cards.
509 (NB. This initial support is for 2.0 channel audio ONLY! ie. stereo.
510 The subwoofer outputs on the Piano 2.1 are not currently supported!)
511 Load: dtoverlay=allo-piano-dac-pcm512x-audio,<param>
512 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
513 Digital volume control.
514 (The default behaviour is that the Digital
515 volume control is limited to a maximum of
516 0dB. ie. it can attenuate but not provide
517 gain. For most users, this will be desired
518 as it will prevent clipping. By appending
519 the 24db_digital_gain parameter, the Digital
520 volume control will allow up to 24dB of
521 gain. If this parameter is enabled, it is the
522 responsibility of the user to ensure that
523 the Digital volume control is set to a value
524 that does not result in clipping/distortion!)
527 Name: allo-piano-dac-plus-pcm512x-audio
528 Info: Configures the Allo Piano DAC (2.1) audio cards.
529 Load: dtoverlay=allo-piano-dac-plus-pcm512x-audio,<param>
530 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
531 Digital volume control.
532 (The default behaviour is that the Digital
533 volume control is limited to a maximum of
534 0dB. ie. it can attenuate but not provide
535 gain. For most users, this will be desired
536 as it will prevent clipping. By appending
537 the 24db_digital_gain parameter, the Digital
538 volume control will allow up to 24dB of
539 gain. If this parameter is enabled, it is the
540 responsibility of the user to ensure that
541 the Digital volume control is set to a value
542 that does not result in clipping/distortion!)
543 glb_mclk This option is only with Kali board. If enabled,
544 MCLK for Kali is used and PLL is disabled for
545 better voice quality. (default Off)
549 Info: Universal device tree overlay for SPI devices
551 Just specify the SPI address and device name ("compatible" property).
552 This overlay lacks any device-specific parameter support!
554 For devices on spi1 or spi2, the interfaces should be enabled
555 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
558 1. SPI NOR flash on spi0.1, maximum SPI clock frequency 45MHz:
559 dtoverlay=anyspi:spi0-1,dev="jedec,spi-nor",speed=45000000
560 2. MCP3204 ADC on spi1.2, maximum SPI clock frequency 500kHz:
561 dtoverlay=anyspi:spi1-2,dev="microchip,mcp3204"
562 Load: dtoverlay=anyspi,<param>=<val>
563 Params: spi<n>-<m> Configure device at spi<n>, cs<m>
565 dev Set device name to search compatible module
567 speed Set SPI clock frequency in Hz
568 (integer, optional, default 500000)
572 Info: Configures the AVAGO APDS9960 digital proximity, ambient light, RGB and
574 Load: dtoverlay=apds9960,<param>=<val>
575 Params: gpiopin GPIO used for INT (default 4)
576 noints Disable the interrupt GPIO line.
580 Info: Configures the Orchard Audio ApplePi-DAC audio card
581 Load: dtoverlay=applepi-dac
585 Name: arducam-pivariety
586 Info: Arducam Pivariety camera module.
587 Uses Unicam 1, which is the standard camera connector on most Pi
589 Load: dtoverlay=arducam-pivariety,<param>=<val>
590 Params: rotation Mounting rotation of the camera sensor (0 or
592 orientation Sensor orientation (0 = front, 1 = rear,
593 2 = external, default external)
594 media-controller Configure use of Media Controller API for
595 configuring the sensor (default on)
596 cam0 Adopt the default configuration for CAM0 on a
597 Compute Module (CSI0, i2c_vc, and cam0_reg).
601 Info: Configures the Atmel AT86RF233 802.15.4 low-power WPAN transceiver,
603 Load: dtoverlay=at86rf233,<param>=<val>
604 Params: interrupt GPIO used for INT (default 23)
605 reset GPIO used for Reset (default 24)
606 sleep GPIO used for Sleep (default 25)
607 speed SPI bus speed in Hz (default 3000000)
608 trim Fine tuning of the internal capacitance
609 arrays (0=+0pF, 15=+4.5pF, default 15)
612 Name: audioinjector-addons
613 Info: Configures the audioinjector.net audio add on soundcards
614 Load: dtoverlay=audioinjector-addons,<param>=<val>
615 Params: non-stop-clocks Keeps the clocks running even when the stream
616 is paused or stopped (default off)
619 Name: audioinjector-bare-i2s
620 Info: Configures the audioinjector.net audio bare i2s soundcard
621 Load: dtoverlay=audioinjector-bare-i2s
625 Name: audioinjector-isolated-soundcard
626 Info: Configures the audioinjector.net isolated soundcard
627 Load: dtoverlay=audioinjector-isolated-soundcard
631 Name: audioinjector-ultra
632 Info: Configures the audioinjector.net ultra soundcard
633 Load: dtoverlay=audioinjector-ultra
637 Name: audioinjector-wm8731-audio
638 Info: Configures the audioinjector.net audio add on soundcard
639 Load: dtoverlay=audioinjector-wm8731-audio
644 Info: Configures the audiosense-pi add on soundcard
645 For more information refer to
646 https://gitlab.com/kakar0t/audiosense-pi
647 Load: dtoverlay=audiosense-pi
652 Info: Switches PWM sound output to GPIOs on the 40-pin header
653 Load: dtoverlay=audremap,<param>=<val>
654 Params: swap_lr Reverse the channel allocation, which will also
655 swap the audio jack outputs (default off)
656 enable_jack Don't switch off the audio jack output
658 pins_12_13 Select GPIOs 12 & 13 (default)
659 pins_18_19 Select GPIOs 18 & 19
663 Info: Overlay that enables WLAN, Bluetooth and the GPIO expander on the
664 balenaFin carrier board for the Raspberry Pi Compute Module 3/3+ Lite.
665 Load: dtoverlay=balena-fin
669 Name: bmp085_i2c-sensor
670 Info: This overlay is now deprecated - see i2c-sensor
675 Info: Enables the ability to use the cap1106 touch sensor as a keyboard
676 Load: dtoverlay=cap1106,<param>=<val>
677 Params: int_pin GPIO pin for interrupt signal (default 23)
681 Info: Configures Chip Dip audio cards.
682 Load: dtoverlay=chipdip-dac
687 Info: Set custom CMA sizes, only use if you know what you are doing, might
688 clash with other overlays like vc4-fkms-v3d and vc4-kms-v3d.
689 Load: dtoverlay=cma,<param>=<val>
690 Params: cma-512 CMA is 512MB (needs 1GB)
691 cma-448 CMA is 448MB (needs 1GB)
692 cma-384 CMA is 384MB (needs 1GB)
693 cma-320 CMA is 320MB (needs 1GB)
694 cma-256 CMA is 256MB (needs 1GB)
695 cma-192 CMA is 192MB (needs 1GB)
699 cma-size CMA size in bytes, 4MB aligned
700 cma-default Use upstream's default value
704 Info: 8" TFT LCD display and touch panel used by cutiepi.io
705 Load: dtoverlay=cutiepi-panel
710 Info: Overlay for the DHT11/DHT21/DHT22 humidity/temperature sensors
711 Also sometimes found with the part number(s) AM230x.
712 Load: dtoverlay=dht11,<param>=<val>
713 Params: gpiopin GPIO connected to the sensor's DATA output.
718 Info: Configures the Dion Audio LOCO DAC-AMP
719 Load: dtoverlay=dionaudio-loco
723 Name: dionaudio-loco-v2
724 Info: Configures the Dion Audio LOCO-V2 DAC-AMP
725 Load: dtoverlay=dionaudio-loco-v2,<param>=<val>
726 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
727 Digital volume control. Enable with
728 "dtoverlay=hifiberry-dacplus,24db_digital_gain"
729 (The default behaviour is that the Digital
730 volume control is limited to a maximum of
731 0dB. ie. it can attenuate but not provide
732 gain. For most users, this will be desired
733 as it will prevent clipping. By appending
734 the 24dB_digital_gain parameter, the Digital
735 volume control will allow up to 24dB of
736 gain. If this parameter is enabled, it is the
737 responsibility of the user to ensure that
738 the Digital volume control is set to a value
739 that does not result in clipping/distortion!)
743 Info: Disable onboard Bluetooth on Pi 3B, 3B+, 3A+, 4B and Zero W, restoring
744 UART0/ttyAMA0 over GPIOs 14 & 15.
745 N.B. To disable the systemd service that initialises the modem so it
746 doesn't use the UART, use 'sudo systemctl disable hciuart'.
747 Load: dtoverlay=disable-bt
752 Info: Disable onboard WLAN on Pi 3B, 3B+, 3A+, 4B and Zero W.
753 Load: dtoverlay=disable-wifi
758 Info: Overlay for a generic 18-bit DPI display
759 This uses GPIOs 0-21 (so no I2C, uart etc.), and activates the output
760 2-3 seconds after the kernel has started.
761 Load: dtoverlay=dpi18
766 Info: Overlay for a generic 18-bit DPI display (in 'mode 6' connection scheme)
767 This uses GPIOs 0-9,12-17,20-25 (so no I2C, uart etc.), and activates
768 the output 3-3 seconds after the kernel has started.
769 Load: dtoverlay=dpi18cpadhi
774 Info: Overlay for a generic 24-bit DPI display
775 This uses GPIOs 0-27 (so no I2C, uart etc.), and activates the output
776 2-3 seconds after the kernel has started.
777 Load: dtoverlay=dpi24
782 Info: Configures the NW Digital Radio DRAWS Hat
784 The board includes an ADC to measure various board values and also
785 provides two analog user inputs on the expansion header. The ADC
786 can be configured for various sample rates and gain values to adjust
787 the input range. Tables describing the two parameters follow.
804 4 = 1600sps (default)
808 Load: dtoverlay=draws,<param>=<val>
809 Params: draws_adc_ch4_gain Sets the full scale resolution of the ADCs
810 input voltage sensor (default 1)
812 draws_adc_ch4_datarate Sets the datarate of the ADCs input voltage
815 draws_adc_ch5_gain Sets the full scale resolution of the ADCs
816 5V rail voltage sensor (default 1)
818 draws_adc_ch5_datarate Sets the datarate of the ADCs 4V rail voltage
821 draws_adc_ch6_gain Sets the full scale resolution of the ADCs
822 AIN2 input (default 2)
824 draws_adc_ch6_datarate Sets the datarate of the ADCs AIN2 input
826 draws_adc_ch7_gain Sets the full scale resolution of the ADCs
827 AIN3 input (default 2)
829 draws_adc_ch7_datarate Sets the datarate of the ADCs AIN3 input
831 alsaname Name of the ALSA audio device (default "draws")
835 Info: Selects the dwc_otg USB controller driver which has fiq support. This
836 is the default on all except the Pi Zero which defaults to dwc2.
837 Load: dtoverlay=dwc-otg
842 Info: Selects the dwc2 USB controller driver
843 Load: dtoverlay=dwc2,<param>=<val>
844 Params: dr_mode Dual role mode: "host", "peripheral" or "otg"
846 g-rx-fifo-size Size of rx fifo size in gadget mode
848 g-np-tx-fifo-size Size of non-periodic tx fifo size in gadget
852 [ The ds1307-rtc overlay has been deleted. See i2c-rtc. ]
856 Info: Overlay for the EDT FT5406 touchscreen on the CSI/DSI I2C interface.
857 This works with the Raspberry Pi 7" touchscreen when not being polled
859 You MUST use either "disable_touchscreen=1" or "ignore_lcd=1" in
860 config.txt to stop the firmware polling the touchscreen.
861 Load: dtoverlay=edt-ft5406,<param>=<val>
862 Params: sizex Touchscreen size x (default 800)
863 sizey Touchscreen size y (default 480)
864 invx Touchscreen inverted x axis
865 invy Touchscreen inverted y axis
866 swapxy Touchscreen swapped x y axis
870 Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI0
871 Load: dtoverlay=enc28j60,<param>=<val>
872 Params: int_pin GPIO used for INT (default 25)
874 speed SPI bus speed (default 12000000)
878 Info: Overlay for the Microchip ENC28J60 Ethernet Controller on SPI2
879 Load: dtoverlay=enc28j60-spi2,<param>=<val>
880 Params: int_pin GPIO used for INT (default 39)
882 speed SPI bus speed (default 12000000)
886 Info: Enables I2C connected EETI EXC3000 multiple touch controller using
887 GPIO 4 (pin 7 on GPIO header) for interrupt.
888 Load: dtoverlay=exc3000,<param>=<val>
889 Params: interrupt GPIO used for interrupt (default 4)
890 sizex Touchscreen size x (default 4096)
891 sizey Touchscreen size y (default 4096)
892 invx Touchscreen inverted x axis
893 invy Touchscreen inverted y axis
894 swapxy Touchscreen swapped x y axis
898 Info: Overlay for SPI-connected displays using the fbtft drivers.
900 This overlay seeks to replace the functionality provided by fbtft_device
901 which is now gone from the kernel.
903 Most displays from fbtft_device have been ported over.
905 dtoverlay=fbtft,spi0-0,rpi-display,reset_pin=23,dc_pin=24,led_pin=18,rotate=270
907 It is also possible to specify the controller (this will use the default
908 init sequence in the driver).
910 dtoverlay=fbtft,spi0-0,ili9341,bgr,reset_pin=23,dc_pin=24,led_pin=18,rotate=270
912 For devices on spi1 or spi2, the interfaces should be enabled
913 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
915 The following features of fbtft_device have not been ported over:
916 - parallel bus is not supported
917 - the init property which overrides the controller initialization
918 sequence is not supported as a parameter due to memory limitations in
919 the bootloader responsible for applying the overlay.
921 See https://github.com/notro/fbtft/wiki/FBTFT-RPI-overlays for how to
924 Load: dtoverlay=fbtft,<param>=<val>
926 spi<n>-<m> Configure device at spi<n>, cs<m>
928 speed SPI bus speed in Hz (default 32000000)
929 cpha Shifted clock phase (CPHA) mode
930 cpol Inverse clock polarity (CPOL) mode
932 adafruit18 Adafruit 1.8
933 adafruit22 Adafruit 2.2 (old)
934 adafruit22a Adafruit 2.2
935 adafruit28 Adafruit 2.8
936 adafruit13m Adafruit 1.3 OLED
937 admatec_c-berry28 C-Berry28
939 er_tftm050_2 ER-TFTM070-2
940 er_tftm070_5 ER-TFTM070-5
942 ew24ha0_9bit EW24HA0 in 9-bit mode
943 freetronicsoled128 Freetronics OLED128
946 itdb28_spi ITDB02-2.8 with SPI interface circuit
947 mi0283qt-2 Watterott MI0283QT-2
948 mi0283qt-9a Watterott MI0283QT-9A
950 nokia3310a Nokia 3310a
953 pitft Adafruit PiTFT 2.8
955 rpi-display Watterott rpi-display
956 sainsmart18 Sainsmart 1.8
957 sainsmart32_spi Sainsmart 3.2 with SPI interfce circuit
958 tinylcd35 TinyLCD 3.5
959 tm022hdh26 Tianma TM022HDH26
960 tontec35_9481 Tontect 3.5 with ILI9481 controller
961 tontec35_9486 Tontect 3.5 with ILI9486 controller
962 waveshare32b Waveshare 3.2
963 waveshare22 Waveshare 2.2
965 bd663474 BD663474 display controller
966 hx8340bn HX8340BN display controller
967 hx8347d HX8347D display controller
968 hx8353d HX8353D display controller
969 hx8357d HX8357D display controller
970 ili9163 ILI9163 display controller
971 ili9320 ILI9320 display controller
972 ili9325 ILI9325 display controller
973 ili9340 ILI9340 display controller
974 ili9341 ILI9341 display controller
975 ili9481 ILI9481 display controller
976 ili9486 ILI9486 display controller
977 pcd8544 PCD8544 display controller
978 ra8875 RA8875 display controller
979 s6d02a1 S6D02A1 display controller
980 s6d1121 S6D1121 display controller
981 seps525 SEPS525 display controller
982 sh1106 SH1106 display controller
983 ssd1289 SSD1289 display controller
984 ssd1305 SSD1305 display controller
985 ssd1306 SSD1306 display controller
986 ssd1325 SSD1325 display controller
987 ssd1331 SSD1331 display controller
988 ssd1351 SSD1351 display controller
989 st7735r ST7735R display controller
990 st7789v ST7789V display controller
991 tls8204 TLS8204 display controller
992 uc1611 UC1611 display controller
993 uc1701 UC1701 display controller
994 upd161704 UPD161704 display controller
996 width Display width in pixels
997 height Display height in pixels
998 regwidth Display controller register width (default is
1000 buswidth Display bus interface width (default 8)
1001 debug Debug output level {0-7}
1002 rotate Display rotation {0, 90, 180, 270} (counter
1003 clockwise). Not supported by all drivers.
1004 bgr Enable BGR mode (default off). Use if Red and
1005 Blue are swapped. Not supported by all drivers.
1006 fps Frames per second (default 30). In effect this
1007 states how long the driver will wait after video
1008 memory has been changed until display update
1009 transfer is started.
1010 txbuflen Length of the FBTFT transmit buffer
1012 startbyte Sets the Start byte used by fb_ili9320,
1013 fb_ili9325 and fb_hx8347d. Common value is 0x70.
1014 gamma String representation of Gamma Curve(s). Driver
1015 specific. Not supported by all drivers.
1016 reset_pin GPIO pin for RESET
1017 dc_pin GPIO pin for D/C
1018 led_pin GPIO pin for LED backlight
1022 Info: Configures the Fe-Pi Audio Sound Card
1023 Load: dtoverlay=fe-pi-audio
1028 Info: A demonstration of the gpio-fsm driver. The GPIOs are chosen to work
1029 nicely with a "traffic-light" display of red, amber and green LEDs on
1030 GPIOs 7, 8 and 25 respectively.
1031 Load: dtoverlay=fsm-demo,<param>=<val>
1032 Params: fsm_debug Enable debug logging (default off)
1036 Info: An overlay for the Ghost amplifier.
1037 Load: dtoverlay=ghost-amp,<param>=<val>
1038 Params: fsm_debug Enable debug logging of the GPIO FSM (default
1043 Info: Enables I2C connected Goodix gt9271 multiple touch controller using
1044 GPIOs 4 and 17 (pins 7 and 11 on GPIO header) for interrupt and reset.
1045 Load: dtoverlay=goodix,<param>=<val>
1046 Params: interrupt GPIO used for interrupt (default 4)
1047 reset GPIO used for reset (default 17)
1050 Name: googlevoicehat-soundcard
1051 Info: Configures the Google voiceHAT soundcard
1052 Load: dtoverlay=googlevoicehat-soundcard
1057 Info: Configure a GPIO pin to control a cooling fan.
1058 Load: dtoverlay=gpio-fan,<param>=<val>
1059 Params: gpiopin GPIO used to control the fan (default 12)
1060 temp Temperature at which the fan switches on, in
1061 millicelcius (default 55000)
1065 Info: Activate a "hog" for a GPIO - request that the kernel configures it as
1066 an output, driven low or high as indicated by the presence or absence
1067 of the active_low parameter. Note that a hogged GPIO is not available
1068 to other drivers or for gpioset/gpioget.
1069 Load: dtoverlay=gpio-hog,<param>=<val>
1070 Params: gpio GPIO pin to hog (default 26)
1071 active_low If set, the hog drives the GPIO low (defaults
1072 to off - the GPIO is driven high)
1076 Info: Use GPIO pin as rc-core style infrared receiver input. The rc-core-
1077 based gpio_ir_recv driver maps received keys directly to a
1078 /dev/input/event* device, all decoding is done by the kernel - LIRC is
1079 not required! The key mapping and other decoding parameters can be
1080 configured by "ir-keytable" tool.
1081 Load: dtoverlay=gpio-ir,<param>=<val>
1082 Params: gpio_pin Input pin number. Default is 18.
1084 gpio_pull Desired pull-up/down state (off, down, up)
1087 invert "1" = invert the input (active-low signalling).
1088 "0" = non-inverted input (active-high
1089 signalling). Default is "1".
1091 rc-map-name Default rc keymap (can also be changed by
1092 ir-keytable), defaults to "rc-rc6-mce"
1096 Info: Use GPIO pin as bit-banged infrared transmitter output.
1097 This is an alternative to "pwm-ir-tx". gpio-ir-tx doesn't require
1098 a PWM so it can be used together with onboard analog audio.
1099 Load: dtoverlay=gpio-ir-tx,<param>=<val>
1100 Params: gpio_pin Output GPIO (default 18)
1102 invert "1" = invert the output (make it active-low).
1103 Default is "0" (active-high).
1107 Info: This is a generic overlay for activating GPIO keypresses using
1108 the gpio-keys library and this dtoverlay. Multiple keys can be
1109 set up using multiple calls to the overlay for configuring
1110 additional buttons or joysticks. You can see available keycodes
1111 at https://github.com/torvalds/linux/blob/v4.12/include/uapi/
1112 linux/input-event-codes.h#L64
1113 Load: dtoverlay=gpio-key,<param>=<val>
1114 Params: gpio GPIO pin to trigger on (default 3)
1115 active_low When this is 1 (active low), a falling
1116 edge generates a key down event and a
1117 rising edge generates a key up event.
1118 When this is 0 (active high), this is
1119 reversed. The default is 1 (active low)
1120 gpio_pull Desired pull-up/down state (off, down, up)
1121 Default is "up". Note that the default pin
1122 (GPIO3) has an external pullup
1123 label Set a label for the key
1124 keycode Set the key code for the button
1129 Info: This is a generic overlay for activating LEDs (or any other component)
1130 by a GPIO pin. Multiple LEDs can be set up using multiple calls to the
1131 overlay. While there are many existing methods to activate LEDs on the
1132 RPi, this method offers some advantages:
1133 1) Does not require any userspace programs.
1134 2) LEDs can be connected to the kernel's led-trigger framework,
1135 and drive the LED based on triggers such as cpu load, heartbeat,
1136 kernel panic, key input, timers and others.
1137 3) LED can be tied to the input state of another GPIO pin.
1138 4) The LED is setup early during the kernel boot process (useful
1139 for cpu/heartbeat/panic triggers).
1141 Typical electrical connection is:
1142 RPI-GPIO.19 -> LED -> 300ohm resister -> RPI-GND
1143 The GPIO pin number can be changed with the 'gpio=' parameter.
1145 To control an LED from userspace, write a 0 or 1 value:
1146 echo 1 > /sys/class/leds/myled1/brightness
1147 The 'myled1' name can be changed with the 'label=' parameter.
1149 To connect the LED to a kernel trigger from userspace:
1150 echo cpu > /sys/class/leds/myled1/trigger
1151 echo heartbeat > /sys/class/leds/myled1/trigger
1152 echo none > /sys/class/leds/myled1/trigger
1153 To connect the LED to GPIO.26 pin (physical pin 37):
1154 echo gpio > /sys/class/leds/myled1/trigger
1155 echo 26 > /sys/class/leds/myled1/gpio
1157 cat /sys/class/leds/myled1/trigger
1159 More information about the Linux kernel LED/Trigger system:
1160 https://www.kernel.org/doc/Documentation/leds/leds-class.rst
1161 https://www.kernel.org/doc/Documentation/leds/ledtrig-oneshot.rst
1162 Load: dtoverlay=gpio-led,<param>=<val>
1163 Params: gpio GPIO pin connected to the LED (default 19)
1164 label The label for this LED. It will appear under
1165 /sys/class/leds/<label> . Default 'myled1'.
1166 trigger Set the led-trigger to connect to this LED.
1167 default 'none' (LED is user-controlled).
1168 Some possible triggers:
1169 cpu - CPU load (all CPUs)
1170 cpu0 - CPU load of first CPU.
1171 mmc - disk activity (all disks)
1172 panic - turn on on kernel panic
1173 heartbeat - indicate system health
1174 gpio - connect to a GPIO input pin (note:
1175 currently the GPIO PIN can not be set
1176 using overlay parameters, must be
1177 done in userspace, see examples above.
1178 active_low Set to 1 to turn invert the LED control
1179 (writing 0 to /sys/class/leds/XXX/brightness
1180 will turn on the GPIO/LED). Default '0'.
1183 Name: gpio-no-bank0-irq
1184 Info: Use this overlay to disable GPIO interrupts for GPIOs in bank 0 (0-27),
1185 which can be useful for UIO drivers.
1186 N.B. Using this overlay will trigger a kernel WARN during booting, but
1187 this can safely be ignored - the system should work as expected.
1188 Load: dtoverlay=gpio-no-bank0-irq
1193 Info: Use this overlay to disable all GPIO interrupts, which can be useful
1194 for user-space GPIO edge detection systems.
1195 Load: dtoverlay=gpio-no-irq
1200 Info: Drives a GPIO high or low on poweroff (including halt). Using this
1201 overlay interferes with the normal power-down sequence, preventing the
1202 kernel from resetting the SoC (a necessary step in a normal power-off
1203 or reboot). This also disables the ability to trigger a boot by driving
1206 The GPIO starts in an inactive state. At poweroff time it is driven
1207 active for 100ms, then inactive for 100ms, then active again. It is
1208 safe to remove the power at any point after the initial activation of
1211 Users of this overlay are required to provide an external mechanism to
1212 switch off the power supply when signalled - failure to do so results
1213 in a kernel BUG, increased power consumption and undefined behaviour.
1214 Load: dtoverlay=gpio-poweroff,<param>=<val>
1215 Params: gpiopin GPIO for signalling (default 26)
1217 active_low Set if the power control device requires a
1218 high->low transition to trigger a power-down.
1219 Note that this will require the support of a
1220 custom dt-blob.bin to prevent a power-down
1221 during the boot process, and that a reboot
1222 will also cause the pin to go low.
1223 input Set if the gpio pin should be configured as
1225 export Set to export the configured pin to sysfs
1226 active_delay_ms Initial GPIO active period (default 100)
1227 inactive_delay_ms Subsequent GPIO inactive period (default 100)
1228 timeout_ms Specify (in ms) how long the kernel waits for
1229 power-down before issuing a WARN (default 3000).
1233 Info: Initiates a shutdown when GPIO pin changes. The given GPIO pin
1234 is configured as an input key that generates KEY_POWER events.
1236 This event is handled by systemd-logind by initiating a
1237 shutdown. Systemd versions older than 225 need an udev rule
1238 enable listening to the input device:
1240 ACTION!="REMOVE", SUBSYSTEM=="input", KERNEL=="event*", \
1241 SUBSYSTEMS=="platform", DRIVERS=="gpio-keys", \
1242 ATTRS{keys}=="116", TAG+="power-switch"
1244 Alternatively this event can be handled also on systems without
1245 systemd, just by traditional SysV init daemon. KEY_POWER event
1246 (keycode 116) needs to be mapped to KeyboardSignal on console
1247 and then kb::kbrequest inittab action which is triggered by
1248 KeyboardSignal from console can be configured to issue system
1249 shutdown. Steps for this configuration are:
1251 Add following lines to the /etc/console-setup/remap.inc file:
1253 # Key Power as special keypress
1254 keycode 116 = KeyboardSignal
1256 Then add following lines to /etc/inittab file:
1258 # Action on special keypress (Key Power)
1259 kb::kbrequest:/sbin/shutdown -t1 -a -h -P now
1261 And finally reload configuration by calling following commands:
1263 # dpkg-reconfigure console-setup
1264 # service console-setup reload
1267 This overlay only handles shutdown. After shutdown, the system
1268 can be powered up again by driving GPIO3 low. The default
1269 configuration uses GPIO3 with a pullup, so if you connect a
1270 button between GPIO3 and GND (pin 5 and 6 on the 40-pin header),
1271 you get a shutdown and power-up button. Please note that
1272 Raspberry Pi 1 Model B rev 1 uses GPIO1 instead of GPIO3.
1273 Load: dtoverlay=gpio-shutdown,<param>=<val>
1274 Params: gpio_pin GPIO pin to trigger on (default 3)
1275 For Raspberry Pi 1 Model B rev 1 set this
1276 explicitly to value 1, e.g.:
1278 dtoverlay=gpio-shutdown,gpio_pin=1
1280 active_low When this is 1 (active low), a falling
1281 edge generates a key down event and a
1282 rising edge generates a key up event.
1283 When this is 0 (active high), this is
1284 reversed. The default is 1 (active low).
1286 gpio_pull Desired pull-up/down state (off, down, up)
1289 Note that the default pin (GPIO3) has an
1290 external pullup. Same applies for GPIO1
1291 on Raspberry Pi 1 Model B rev 1.
1293 debounce Specify the debounce interval in milliseconds
1298 Info: Configures an HD44780 compatible LCD display. Uses 4 gpio pins for
1299 data, 2 gpio pins for enable and register select and 1 optional pin
1300 for enabling/disabling the backlight display.
1301 Load: dtoverlay=hd44780-lcd,<param>=<val>
1302 Params: pin_d4 GPIO pin for data pin D4 (default 6)
1304 pin_d5 GPIO pin for data pin D5 (default 13)
1306 pin_d6 GPIO pin for data pin D6 (default 19)
1308 pin_d7 GPIO pin for data pin D7 (default 26)
1310 pin_en GPIO pin for "Enable" (default 21)
1312 pin_rs GPIO pin for "Register Select" (default 20)
1314 pin_bl Optional pin for enabling/disabling the
1315 display backlight. (default disabled)
1317 display_height Height of the display in characters
1319 display_width Width of the display in characters
1322 Name: hdmi-backlight-hwhack-gpio
1323 Info: Devicetree overlay for GPIO based backlight on/off capability.
1324 Use this if you have one of those HDMI displays whose backlight cannot
1325 be controlled via DPMS over HDMI and plan to do a little soldering to
1326 use an RPi gpio pin for on/off switching. See:
1327 https://www.waveshare.com/wiki/7inch_HDMI_LCD_(C)#Backlight_Control
1328 Load: dtoverlay=hdmi-backlight-hwhack-gpio,<param>=<val>
1329 Params: gpio_pin GPIO pin used (default 17)
1330 active_low Set this to 1 if the display backlight is
1331 switched on when the wire goes low.
1332 Leave the default (value 0) if the backlight
1333 expects a high to switch it on.
1337 Info: Configures the HifiBerry Amp and Amp+ audio cards
1338 Load: dtoverlay=hifiberry-amp
1342 Name: hifiberry-amp100
1343 Info: Configures the HifiBerry AMP100 audio card
1344 Load: dtoverlay=hifiberry-amp100,<param>=<val>
1345 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
1346 Digital volume control. Enable with
1347 "dtoverlay=hifiberry-amp100,24db_digital_gain"
1348 (The default behaviour is that the Digital
1349 volume control is limited to a maximum of
1350 0dB. ie. it can attenuate but not provide
1351 gain. For most users, this will be desired
1352 as it will prevent clipping. By appending
1353 the 24dB_digital_gain parameter, the Digital
1354 volume control will allow up to 24dB of
1355 gain. If this parameter is enabled, it is the
1356 responsibility of the user to ensure that
1357 the Digital volume control is set to a value
1358 that does not result in clipping/distortion!)
1359 slave Force DAC+ Pro into slave mode, using Pi as
1360 master for bit clock and frame clock.
1361 leds_off If set to 'true' the onboard indicator LEDs
1362 are switched off at all times.
1363 auto_mute If set to 'true' the amplifier is automatically
1364 muted when the DAC is not playing.
1365 mute_ext_ctl The amplifier's HW mute control is enabled
1366 in ALSA mixer and set to <val>.
1367 Will be overwritten by ALSA user settings.
1371 Info: Configures the HifiBerry DAC audio cards
1372 Load: dtoverlay=hifiberry-dac
1376 Name: hifiberry-dacplus
1377 Info: Configures the HifiBerry DAC+ audio card
1378 Load: dtoverlay=hifiberry-dacplus,<param>=<val>
1379 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
1380 Digital volume control. Enable with
1381 "dtoverlay=hifiberry-dacplus,24db_digital_gain"
1382 (The default behaviour is that the Digital
1383 volume control is limited to a maximum of
1384 0dB. ie. it can attenuate but not provide
1385 gain. For most users, this will be desired
1386 as it will prevent clipping. By appending
1387 the 24dB_digital_gain parameter, the Digital
1388 volume control will allow up to 24dB of
1389 gain. If this parameter is enabled, it is the
1390 responsibility of the user to ensure that
1391 the Digital volume control is set to a value
1392 that does not result in clipping/distortion!)
1393 slave Force DAC+ Pro into slave mode, using Pi as
1394 master for bit clock and frame clock.
1395 leds_off If set to 'true' the onboard indicator LEDs
1396 are switched off at all times.
1399 Name: hifiberry-dacplusadc
1400 Info: Configures the HifiBerry DAC+ADC audio card
1401 Load: dtoverlay=hifiberry-dacplusadc,<param>=<val>
1402 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
1403 Digital volume control. Enable with
1404 "dtoverlay=hifiberry-dacplus,24db_digital_gain"
1405 (The default behaviour is that the Digital
1406 volume control is limited to a maximum of
1407 0dB. ie. it can attenuate but not provide
1408 gain. For most users, this will be desired
1409 as it will prevent clipping. By appending
1410 the 24dB_digital_gain parameter, the Digital
1411 volume control will allow up to 24dB of
1412 gain. If this parameter is enabled, it is the
1413 responsibility of the user to ensure that
1414 the Digital volume control is set to a value
1415 that does not result in clipping/distortion!)
1416 slave Force DAC+ Pro into slave mode, using Pi as
1417 master for bit clock and frame clock.
1418 leds_off If set to 'true' the onboard indicator LEDs
1419 are switched off at all times.
1422 Name: hifiberry-dacplusadcpro
1423 Info: Configures the HifiBerry DAC+ADC PRO audio card
1424 Load: dtoverlay=hifiberry-dacplusadcpro,<param>=<val>
1425 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
1426 Digital volume control. Enable with
1427 "dtoverlay=hifiberry-dacplusadcpro,24db_digital_gain"
1428 (The default behaviour is that the Digital
1429 volume control is limited to a maximum of
1430 0dB. ie. it can attenuate but not provide
1431 gain. For most users, this will be desired
1432 as it will prevent clipping. By appending
1433 the 24dB_digital_gain parameter, the Digital
1434 volume control will allow up to 24dB of
1435 gain. If this parameter is enabled, it is the
1436 responsibility of the user to ensure that
1437 the Digital volume control is set to a value
1438 that does not result in clipping/distortion!)
1439 slave Force DAC+ADC Pro into slave mode, using Pi as
1440 master for bit clock and frame clock.
1441 leds_off If set to 'true' the onboard indicator LEDs
1442 are switched off at all times.
1445 Name: hifiberry-dacplusdsp
1446 Info: Configures the HifiBerry DAC+DSP audio card
1447 Load: dtoverlay=hifiberry-dacplusdsp
1451 Name: hifiberry-dacplushd
1452 Info: Configures the HifiBerry DAC+ HD audio card
1453 Load: dtoverlay=hifiberry-dacplushd
1457 Name: hifiberry-digi
1458 Info: Configures the HifiBerry Digi and Digi+ audio card
1459 Load: dtoverlay=hifiberry-digi
1463 Name: hifiberry-digi-pro
1464 Info: Configures the HifiBerry Digi+ Pro audio card
1465 Load: dtoverlay=hifiberry-digi-pro
1470 Info: Enables "High Peripheral" mode
1471 Load: dtoverlay=highperi
1476 Info: HY28A - 2.8" TFT LCD Display Module by HAOYU Electronics
1477 Default values match Texy's display shield
1478 Load: dtoverlay=hy28a,<param>=<val>
1479 Params: speed Display SPI bus speed
1481 rotate Display rotation {0,90,180,270}
1483 fps Delay between frame updates
1485 debug Debug output level {0-7}
1487 xohms Touchpanel sensitivity (X-plate resistance)
1489 resetgpio GPIO used to reset controller
1491 ledgpio GPIO used to control backlight
1495 Info: HY28B - 2.8" TFT LCD Display Module by HAOYU Electronics
1496 Default values match Texy's display shield
1497 Load: dtoverlay=hy28b,<param>=<val>
1498 Params: speed Display SPI bus speed
1500 rotate Display rotation {0,90,180,270}
1502 fps Delay between frame updates
1504 debug Debug output level {0-7}
1506 xohms Touchpanel sensitivity (X-plate resistance)
1508 resetgpio GPIO used to reset controller
1510 ledgpio GPIO used to control backlight
1514 Info: HY28B 2017 version - 2.8" TFT LCD Display Module by HAOYU Electronics
1515 Default values match Texy's display shield
1516 Load: dtoverlay=hy28b-2017,<param>=<val>
1517 Params: speed Display SPI bus speed
1519 rotate Display rotation {0,90,180,270}
1521 fps Delay between frame updates
1523 debug Debug output level {0-7}
1525 xohms Touchpanel sensitivity (X-plate resistance)
1527 resetgpio GPIO used to reset controller
1529 ledgpio GPIO used to control backlight
1533 Info: Configures the Audiophonics I-SABRE Q2M DAC
1534 Load: dtoverlay=i-sabre-q2m
1539 Info: Fall back to the i2c_bcm2708 driver for the i2c_arm bus.
1540 Load: dtoverlay=i2c-bcm2708
1545 Info: Adds support for a number of I2C fan controllers
1546 Load: dtoverlay=i2c-fan,<param>=<val>
1547 Params: addr Sets the address for the fan controller. Note
1548 that the device must be configured to use the
1551 i2c0 Choose the I2C0 bus on GPIOs 0&1
1553 i2c_csi_dsi Choose the I2C0 bus on GPIOs 44&45
1555 minpwm PWM setting for the fan when the SoC is below
1556 mintemp (range 0-255. default 0)
1557 maxpwm PWM setting for the fan when the SoC is above
1558 maxtemp (range 0-255. default 255)
1559 midtemp Temperature (in millicelcius) at which the fan
1560 begins to speed up (default 50000)
1562 midtemp_hyst Temperature delta (in millicelcius) below
1563 mintemp at which the fan will drop to minrpm
1566 maxtemp Temperature (in millicelcius) at which the fan
1567 will be held at maxrpm (default 70000)
1569 maxtemp_hyst Temperature delta (in millicelcius) below
1570 maxtemp at which the fan begins to slow down
1573 emc2301 Select the Microchip EMC230x controller family
1574 - EMC2301, EMC2302, EMC2303, EMC2305.
1578 Info: Adds support for software i2c controller on gpio pins
1579 Load: dtoverlay=i2c-gpio,<param>=<val>
1580 Params: i2c_gpio_sda GPIO used for I2C data (default "23")
1582 i2c_gpio_scl GPIO used for I2C clock (default "24")
1584 i2c_gpio_delay_us Clock delay in microseconds
1585 (default "2" = ~100kHz)
1587 bus Set to a unique, non-zero value if wanting
1588 multiple i2c-gpio busses. If set, will be used
1589 as the preferred bus number (/dev/i2c-<n>). If
1590 not set, the default value is 0, but the bus
1591 number will be dynamically assigned - probably
1596 Info: Adds support for a number of I2C bus multiplexers on i2c_arm
1597 Load: dtoverlay=i2c-mux,<param>=<val>
1598 Params: pca9542 Select the NXP PCA9542 device
1600 pca9545 Select the NXP PCA9545 device
1602 pca9548 Select the NXP PCA9548 device
1604 addr Change I2C address of the device (default 0x70)
1607 [ The i2c-mux-pca9548a overlay has been deleted. See i2c-mux. ]
1610 Name: i2c-pwm-pca9685a
1611 Info: Adds support for an NXP PCA9685A I2C PWM controller on i2c_arm
1612 Load: dtoverlay=i2c-pwm-pca9685a,<param>=<val>
1613 Params: addr I2C address of PCA9685A (default 0x40)
1617 Info: Adds support for a number of I2C Real Time Clock devices
1618 Load: dtoverlay=i2c-rtc,<param>=<val>
1619 Params: abx80x Select one of the ABx80x family:
1620 AB0801, AB0803, AB0804, AB0805,
1621 AB1801, AB1803, AB1804, AB1805
1623 bq32000 Select the TI BQ32000 device
1625 ds1307 Select the DS1307 device
1627 ds1339 Select the DS1339 device
1629 ds1340 Select the DS1340 device
1631 ds3231 Select the DS3231 device
1633 m41t62 Select the M41T62 device
1635 mcp7940x Select the MCP7940x device
1637 mcp7941x Select the MCP7941x device
1639 pcf2127 Select the PCF2127 device
1641 pcf2129 Select the PCF2129 device
1643 pcf85063 Select the PCF85063 device
1645 pcf85063a Select the PCF85063A device
1647 pcf8523 Select the PCF8523 device
1649 pcf85363 Select the PCF85363 device
1651 pcf8563 Select the PCF8563 device
1653 rv1805 Select the Micro Crystal RV1805 device
1655 rv3028 Select the Micro Crystal RV3028 device
1657 sd3078 Select the ZXW Shenzhen whwave SD3078 device
1659 s35390a Select the ABLIC S35390A device
1661 i2c0 Choose the I2C0 bus on GPIOs 0&1
1663 i2c_csi_dsi Choose the I2C0 bus on GPIOs 44&45
1665 addr Sets the address for the RTC. Note that the
1666 device must be configured to use the specified
1669 trickle-diode-disable Do not use the internal trickle charger diode
1672 trickle-diode-type Diode type for trickle charge - "standard" or
1673 "schottky" (ABx80x and RV1805 only)
1675 trickle-resistor-ohms Resistor value for trickle charge (DS1339,
1676 ABx80x, RV1805, RV3028)
1678 wakeup-source Specify that the RTC can be used as a wakeup
1681 backup-switchover-mode Backup power supply switch mode. Must be 0 for
1682 off or 1 for Vdd < VBackup (RV3028 only)
1686 Info: Adds support for a number of I2C Real Time Clock devices
1687 using the software i2c controller
1688 Load: dtoverlay=i2c-rtc-gpio,<param>=<val>
1689 Params: abx80x Select one of the ABx80x family:
1690 AB0801, AB0803, AB0804, AB0805,
1691 AB1801, AB1803, AB1804, AB1805
1693 bq32000 Select the TI BQ32000 device
1695 ds1307 Select the DS1307 device
1697 ds1339 Select the DS1339 device
1699 ds1340 Select the DS1340 device
1701 ds3231 Select the DS3231 device
1703 m41t62 Select the M41T62 device
1705 mcp7940x Select the MCP7940x device
1707 mcp7941x Select the MCP7941x device
1709 pcf2127 Select the PCF2127 device
1711 pcf2129 Select the PCF2129 device
1713 pcf85063 Select the PCF85063 device
1715 pcf85063a Select the PCF85063A device
1717 pcf8523 Select the PCF8523 device
1719 pcf85363 Select the PCF85363 device
1721 pcf8563 Select the PCF8563 device
1723 rv1805 Select the Micro Crystal RV1805 device
1725 rv3028 Select the Micro Crystal RV3028 device
1727 sd3078 Select the ZXW Shenzhen whwave SD3078 device
1729 s35390a Select the ABLIC S35390A device
1731 addr Sets the address for the RTC. Note that the
1732 device must be configured to use the specified
1735 trickle-diode-disable Do not use the internal trickle charger diode
1738 trickle-diode-type Diode type for trickle charge - "standard" or
1739 "schottky" (ABx80x and RV1805 only)
1741 trickle-resistor-ohms Resistor value for trickle charge (DS1339,
1742 ABx80x, RV1805, RV3028)
1744 wakeup-source Specify that the RTC can be used as a wakeup
1747 backup-switchover-mode Backup power supply switch mode. Must be 0 for
1748 off or 1 for Vdd < VBackup (RV3028 only)
1750 i2c_gpio_sda GPIO used for I2C data (default "23")
1752 i2c_gpio_scl GPIO used for I2C clock (default "24")
1754 i2c_gpio_delay_us Clock delay in microseconds
1755 (default "2" = ~100kHz)
1759 Info: Adds support for a number of I2C barometric pressure, temperature,
1760 light level and chemical sensors on i2c_arm
1761 Load: dtoverlay=i2c-sensor,<param>=<val>
1762 Params: addr Set the address for the BH1750, BME280, BME680,
1763 BMP280, CCS811, DS1621, HDC100X, LM75, SHT3x or
1766 bh1750 Select the Rohm BH1750 ambient light sensor
1767 Valid addresses 0x23 or 0x5c, default 0x23
1769 bme280 Select the Bosch Sensortronic BME280
1770 Valid addresses 0x76-0x77, default 0x76
1772 bme680 Select the Bosch Sensortronic BME680
1773 Valid addresses 0x76-0x77, default 0x76
1775 bmp085 Select the Bosch Sensortronic BMP085
1777 bmp180 Select the Bosch Sensortronic BMP180
1779 bmp280 Select the Bosch Sensortronic BMP280
1780 Valid addresses 0x76-0x77, default 0x76
1782 ccs811 Select the AMS CCS811 digital gas sensor
1783 Valid addresses 0x5a-0x5b, default 0x5b
1785 ds1621 Select the Dallas Semiconductors DS1621 temp
1786 sensor. Valid addresses 0x48-0x4f, default 0x48
1788 hdc100x Select the Texas Instruments HDC100x temp sensor
1789 Valid addresses 0x40-0x43, default 0x40
1791 htu21 Select the HTU21 temperature and humidity sensor
1793 int_pin Set the GPIO to use for interrupts (max30102
1796 lm75 Select the Maxim LM75 temperature sensor
1797 Valid addresses 0x48-0x4f, default 0x4f
1799 lm75addr Deprecated - use addr parameter instead
1801 max17040 Select the Maxim Integrated MAX17040 battery
1804 max30102 Select the Maxim Integrated MAX30102 heart-rate
1805 and blood-oxygen sensor
1807 sht3x Select the Sensiron SHT3x temperature and
1808 humidity sensor. Valid addresses 0x44-0x45,
1811 si7020 Select the Silicon Labs Si7013/20/21 humidity/
1814 sps30 Select the Sensirion SPS30 particulate matter
1815 sensor. Fixed address 0x69.
1817 sgp30 Select the Sensirion SGP30 VOC sensor.
1820 tmp102 Select the Texas Instruments TMP102 temp sensor
1821 Valid addresses 0x48-0x4b, default 0x48
1823 tsl4531 Select the AMS TSL4531 digital ambient light
1826 veml6070 Select the Vishay VEML6070 ultraviolet light
1831 Info: Change i2c0 pin usage. Not all pin combinations are usable on all
1832 platforms - platforms other then Compute Modules can only use this
1833 to disable transaction combining.
1834 Do NOT use in conjunction with dtparam=i2c_vc=on. From the 5.4 kernel
1835 onwards the base DT includes the use of i2c_mux_pinctrl to expose two
1836 muxings of BSC0 - GPIOs 0&1, and whichever combination is used for the
1837 camera and display connectors. This overlay disables that mux and
1838 configures /dev/i2c0 to point at whichever set of pins is requested.
1839 dtparam=i2c_vc=on will try and enable the mux, so combining the two
1840 will cause conflicts.
1841 Load: dtoverlay=i2c0,<param>=<val>
1842 Params: pins_0_1 Use pins 0 and 1 (default)
1843 pins_28_29 Use pins 28 and 29
1844 pins_44_45 Use pins 44 and 45
1845 pins_46_47 Use pins 46 and 47
1846 combine Allow transactions to be combined (default
1851 Info: Deprecated, legacy version of i2c0.
1856 Info: Change i2c1 pin usage. Not all pin combinations are usable on all
1857 platforms - platforms other then Compute Modules can only use this
1858 to disable transaction combining.
1859 Load: dtoverlay=i2c1,<param>=<val>
1860 Params: pins_2_3 Use pins 2 and 3 (default)
1861 pins_44_45 Use pins 44 and 45
1862 combine Allow transactions to be combined (default
1867 Info: Deprecated, legacy version of i2c1.
1872 Info: Enable the i2c3 bus. BCM2711 only.
1873 Load: dtoverlay=i2c3,<param>
1874 Params: pins_2_3 Use GPIOs 2 and 3
1875 pins_4_5 Use GPIOs 4 and 5 (default)
1876 baudrate Set the baudrate for the interface (default
1881 Info: Enable the i2c4 bus. BCM2711 only.
1882 Load: dtoverlay=i2c4,<param>
1883 Params: pins_6_7 Use GPIOs 6 and 7
1884 pins_8_9 Use GPIOs 8 and 9 (default)
1885 baudrate Set the baudrate for the interface (default
1890 Info: Enable the i2c5 bus. BCM2711 only.
1891 Load: dtoverlay=i2c5,<param>
1892 Params: pins_10_11 Use GPIOs 10 and 11
1893 pins_12_13 Use GPIOs 12 and 13 (default)
1894 baudrate Set the baudrate for the interface (default
1899 Info: Enable the i2c6 bus. BCM2711 only.
1900 Load: dtoverlay=i2c6,<param>
1901 Params: pins_0_1 Use GPIOs 0 and 1
1902 pins_22_23 Use GPIOs 22 and 23 (default)
1903 baudrate Set the baudrate for the interface (default
1908 Info: move I2S function block to GPIO 28 to 31
1909 Load: dtoverlay=i2s-gpio28-31
1914 Info: Enables I2C connected Ilitek 251x multiple touch controller using
1915 GPIO 4 (pin 7 on GPIO header) for interrupt.
1916 Load: dtoverlay=ilitek251x,<param>=<val>
1917 Params: interrupt GPIO used for interrupt (default 4)
1918 sizex Touchscreen size x, horizontal resolution of
1919 touchscreen (in pixels)
1920 sizey Touchscreen size y, vertical resolution of
1921 touchscreen (in pixels)
1925 Info: Sony IMX219 camera module.
1926 Uses Unicam 1, which is the standard camera connector on most Pi
1928 Load: dtoverlay=imx219,<param>=<val>
1929 Params: rotation Mounting rotation of the camera sensor (0 or
1931 orientation Sensor orientation (0 = front, 1 = rear,
1932 2 = external, default external)
1933 media-controller Configure use of Media Controller API for
1934 configuring the sensor (default on)
1935 cam0 Adopt the default configuration for CAM0 on a
1936 Compute Module (CSI0, i2c_vc, and cam0_reg).
1937 vcm Configure a VCM focus drive on the sensor.
1941 Info: Sony IMX258 camera module.
1942 Uses Unicam 1, which is the standard camera connector on most Pi
1944 Load: dtoverlay=imx258,<param>=<val>
1945 Params: rotation Mounting rotation of the camera sensor (0 or
1947 orientation Sensor orientation (0 = front, 1 = rear,
1948 2 = external, default external)
1949 media-controller Configure use of Media Controller API for
1950 configuring the sensor (default on)
1951 cam0 Adopt the default configuration for CAM0 on a
1952 Compute Module (CSI0, i2c_vc, and cam0_reg).
1953 vcm Configure a VCM focus drive on the sensor.
1954 4lane Enable 4 CSI2 lanes. This requires a Compute
1955 Module (1, 3, or 4).
1959 Info: Sony IMX290 camera module.
1960 Uses Unicam 1, which is the standard camera connector on most Pi
1961 variants. NB This currently uses 4 CSI2 data lanes and therefore will
1963 Load: dtoverlay=imx290,<param>
1964 Params: 4lane Enable 4 CSI2 lanes. This requires a Compute
1965 Module (1, 3, or 4).
1966 clock-frequency Sets the clock frequency to match that used on
1968 Modules from Vision Components use 37.125MHz
1969 (the default), whilst those from Innomaker use
1971 mono Denote that the module is a mono sensor.
1972 orientation Sensor orientation (0 = front, 1 = rear,
1973 2 = external, default external)
1974 rotation Mounting rotation of the camera sensor (0 or
1976 media-controller Configure use of Media Controller API for
1977 configuring the sensor (default on)
1978 cam0 Adopt the default configuration for CAM0 on a
1979 Compute Module (CSI0, i2c_vc, and cam0_reg).
1983 Info: Sony IMX296 camera module.
1984 Uses Unicam 1, which is the standard camera connector on most Pi
1986 Load: dtoverlay=imx296,<param>=<val>
1987 Params: rotation Mounting rotation of the camera sensor (0 or
1989 orientation Sensor orientation (0 = front, 1 = rear,
1990 2 = external, default external)
1991 media-controller Configure use of Media Controller API for
1992 configuring the sensor (default on)
1993 cam0 Adopt the default configuration for CAM0 on a
1994 Compute Module (CSI0, i2c_vc, and cam0_reg).
1998 Info: Sony IMX378 camera module.
1999 Uses Unicam 1, which is the standard camera connector on most Pi
2001 Load: dtoverlay=imx378,<param>=<val>
2002 Params: rotation Mounting rotation of the camera sensor (0 or
2004 orientation Sensor orientation (0 = front, 1 = rear,
2005 2 = external, default external)
2006 media-controller Configure use of Media Controller API for
2007 configuring the sensor (default on)
2008 cam0 Adopt the default configuration for CAM0 on a
2009 Compute Module (CSI0, i2c_vc, and cam0_reg).
2013 Info: Sony IMX477 camera module.
2014 Uses Unicam 1, which is the standard camera connector on most Pi
2016 Load: dtoverlay=imx477,<param>=<val>
2017 Params: rotation Mounting rotation of the camera sensor (0 or
2019 orientation Sensor orientation (0 = front, 1 = rear,
2020 2 = external, default external)
2021 media-controller Configure use of Media Controller API for
2022 configuring the sensor (default on)
2023 cam0 Adopt the default configuration for CAM0 on a
2024 Compute Module (CSI0, i2c_vc, and cam0_reg).
2028 Info: Sony IMX519 camera module.
2029 Uses Unicam 1, which is the standard camera connector on most Pi
2031 Load: dtoverlay=imx519,<param>=<val>
2032 Params: rotation Mounting rotation of the camera sensor (0 or
2034 orientation Sensor orientation (0 = front, 1 = rear,
2035 2 = external, default external)
2036 media-controller Configure use of Media Controller API for
2037 configuring the sensor (default on)
2038 cam0 Adopt the default configuration for CAM0 on a
2039 Compute Module (CSI0, i2c_vc, and cam0_reg).
2043 Info: Configures the IQaudio Codec audio card
2044 Load: dtoverlay=iqaudio-codec
2049 Info: Configures the IQaudio DAC audio card
2050 Load: dtoverlay=iqaudio-dac,<param>
2051 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
2052 Digital volume control. Enable with
2053 "dtoverlay=iqaudio-dac,24db_digital_gain"
2054 (The default behaviour is that the Digital
2055 volume control is limited to a maximum of
2056 0dB. ie. it can attenuate but not provide
2057 gain. For most users, this will be desired
2058 as it will prevent clipping. By appending
2059 the 24db_digital_gain parameter, the Digital
2060 volume control will allow up to 24dB of
2061 gain. If this parameter is enabled, it is the
2062 responsibility of the user to ensure that
2063 the Digital volume control is set to a value
2064 that does not result in clipping/distortion!)
2067 Name: iqaudio-dacplus
2068 Info: Configures the IQaudio DAC+ audio card
2069 Load: dtoverlay=iqaudio-dacplus,<param>=<val>
2070 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
2071 Digital volume control. Enable with
2072 "dtoverlay=iqaudio-dacplus,24db_digital_gain"
2073 (The default behaviour is that the Digital
2074 volume control is limited to a maximum of
2075 0dB. ie. it can attenuate but not provide
2076 gain. For most users, this will be desired
2077 as it will prevent clipping. By appending
2078 the 24db_digital_gain parameter, the Digital
2079 volume control will allow up to 24dB of
2080 gain. If this parameter is enabled, it is the
2081 responsibility of the user to ensure that
2082 the Digital volume control is set to a value
2083 that does not result in clipping/distortion!)
2084 auto_mute_amp If specified, unmute/mute the IQaudIO amp when
2085 starting/stopping audio playback.
2086 unmute_amp If specified, unmute the IQaudIO amp once when
2087 the DAC driver module loads.
2090 Name: iqaudio-digi-wm8804-audio
2091 Info: Configures the IQAudIO Digi WM8804 audio card
2092 Load: dtoverlay=iqaudio-digi-wm8804-audio,<param>=<val>
2093 Params: card_name Override the default, "IQAudIODigi", card name.
2094 dai_name Override the default, "IQAudIO Digi", dai name.
2095 dai_stream_name Override the default, "IQAudIO Digi HiFi",
2100 Info: Enables I2C connected Azoteq IQS550 trackpad/touchscreen controller
2101 using GPIO 4 (pin 7 on GPIO header) for interrupt.
2102 Load: dtoverlay=iqs550,<param>=<val>
2103 Params: interrupt GPIO used for interrupt (default 4)
2104 reset GPIO used for reset (optional)
2105 sizex Touchscreen size x (default 800)
2106 sizey Touchscreen size y (default 480)
2107 invx Touchscreen inverted x axis
2108 invy Touchscreen inverted y axis
2109 swapxy Touchscreen swapped x y axis
2113 Info: Infineon irs1125 TOF camera module.
2114 Uses Unicam 1, which is the standard camera connector on most Pi
2116 Load: dtoverlay=irs1125,<param>=<val>
2117 Params: media-controller Configure use of Media Controller API for
2118 configuring the sensor (default off)
2119 cam0 Adopt the default configuration for CAM0 on a
2120 Compute Module (CSI0, i2c_vc, and cam0_reg).
2124 Info: Adds support for JEDEC-compliant SPI NOR flash devices. (Note: The
2125 "jedec,spi-nor" kernel driver was formerly known as "m25p80".)
2126 Load: dtoverlay=jedec-spi-nor,<param>=<val>
2127 Params: flash-spi<n>-<m> Enables flash device on SPI<n>, CS#<m>.
2128 flash-fastr-spi<n>-<m> Enables flash device with fast read capability
2133 Info: Simultaneous usage of an justboom-dac and justboom-digi based
2135 Load: dtoverlay=justboom-both,<param>=<val>
2136 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
2137 Digital volume control. Enable with
2138 "dtoverlay=justboom-dac,24db_digital_gain"
2139 (The default behaviour is that the Digital
2140 volume control is limited to a maximum of
2141 0dB. ie. it can attenuate but not provide
2142 gain. For most users, this will be desired
2143 as it will prevent clipping. By appending
2144 the 24dB_digital_gain parameter, the Digital
2145 volume control will allow up to 24dB of
2146 gain. If this parameter is enabled, it is the
2147 responsibility of the user to ensure that
2148 the Digital volume control is set to a value
2149 that does not result in clipping/distortion!)
2153 Info: Configures the JustBoom DAC HAT, Amp HAT, DAC Zero and Amp Zero audio
2155 Load: dtoverlay=justboom-dac,<param>=<val>
2156 Params: 24db_digital_gain Allow gain to be applied via the PCM512x codec
2157 Digital volume control. Enable with
2158 "dtoverlay=justboom-dac,24db_digital_gain"
2159 (The default behaviour is that the Digital
2160 volume control is limited to a maximum of
2161 0dB. ie. it can attenuate but not provide
2162 gain. For most users, this will be desired
2163 as it will prevent clipping. By appending
2164 the 24dB_digital_gain parameter, the Digital
2165 volume control will allow up to 24dB of
2166 gain. If this parameter is enabled, it is the
2167 responsibility of the user to ensure that
2168 the Digital volume control is set to a value
2169 that does not result in clipping/distortion!)
2173 Info: Configures the JustBoom Digi HAT and Digi Zero audio cards
2174 Load: dtoverlay=justboom-digi
2179 Info: This overlay has been deprecated and removed - see gpio-ir
2184 Info: Adds support for the ltc294x family of battery gauges
2185 Load: dtoverlay=ltc294x,<param>=<val>
2186 Params: ltc2941 Select the ltc2941 device
2188 ltc2942 Select the ltc2942 device
2190 ltc2943 Select the ltc2943 device
2192 ltc2944 Select the ltc2944 device
2194 resistor-sense The sense resistor value in milli-ohms.
2195 Can be a 32-bit negative value when the battery
2196 has been connected to the wrong end of the
2199 prescaler-exponent Range and accuracy of the gauge. The value is
2200 programmed into the chip only if it differs
2201 from the current setting.
2203 - Default value is 128
2204 - the exponent is in the range 0-7 (default 7)
2205 See the datasheet for more information.
2209 Info: Configures the Maxim MAX98357A I2S DAC
2210 Load: dtoverlay=max98357a,<param>=<val>
2211 Params: no-sdmode Driver does not manage the state of the DAC's
2212 SD_MODE pin (i.e. chip is always on).
2213 sdmode-pin integer, GPIO pin connected to the SD_MODE input
2214 of the DAC (default GPIO4 if parameter omitted).
2218 Info: Configure a MAX6675, MAX31855 or MAX31856 thermocouple as an IIO device.
2220 For devices on spi1 or spi2, the interfaces should be enabled
2221 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
2222 The overlay expects to disable the relevant spidev node, so also using
2223 e.g. cs0_spidev=off is unnecessary.
2226 MAX31855 on /dev/spidev0.0
2227 dtoverlay=maxtherm,spi0-0,max31855
2228 MAX31856 using a type J thermocouple on /dev/spidev2.1
2230 dtoverlay=maxtherm,spi2-1,max31856,type_j
2232 Load: dtoverlay=maxtherm,<param>=<val>
2233 Params: spi<n>-<m> Configure device at spi<n>, cs<m>
2235 max6675 Enable support for the MAX6675 (default)
2236 max31855 Enable support for the MAX31855
2237 max31855e Enable support for the MAX31855E
2238 max31855j Enable support for the MAX31855J
2239 max31855k Enable support for the MAX31855K
2240 max31855n Enable support for the MAX31855N
2241 max31855r Enable support for the MAX31855R
2242 max31855s Enable support for the MAX31855S
2243 max31855t Enable support for the MAX31855T
2244 max31856 Enable support for the MAX31856 (with type K)
2245 type_b Select a type B sensor for max31856
2246 type_e Select a type E sensor for max31856
2247 type_j Select a type J sensor for max31856
2248 type_k Select a type K sensor for max31856
2249 type_n Select a type N sensor for max31856
2250 type_r Select a type R sensor for max31856
2251 type_s Select a type S sensor for max31856
2252 type_t Select a type T sensor for max31856
2256 Info: Configures the mbed AudioCODEC (TLV320AIC23B)
2257 Load: dtoverlay=mbed-dac
2262 Info: Configures the MCP23017 I2C GPIO expander
2263 Load: dtoverlay=mcp23017,<param>=<val>
2264 Params: gpiopin Gpio pin connected to the INTA output of the
2265 MCP23017 (default: 4)
2267 addr I2C address of the MCP23017 (default: 0x20)
2269 mcp23008 Configure an MCP23008 instead.
2270 noints Disable the interrupt GPIO line.
2274 Info: Configures the MCP23S08/17 SPI GPIO expanders.
2275 If devices are present on SPI1 or SPI2, those interfaces must be enabled
2276 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
2277 If interrupts are enabled for a device on a given CS# on a SPI bus, that
2278 device must be the only one present on that SPI bus/CS#.
2279 Load: dtoverlay=mcp23s17,<param>=<val>
2280 Params: s08-spi<n>-<m>-present 4-bit integer, bitmap indicating MCP23S08
2281 devices present on SPI<n>, CS#<m>
2283 s17-spi<n>-<m>-present 8-bit integer, bitmap indicating MCP23S17
2284 devices present on SPI<n>, CS#<m>
2286 s08-spi<n>-<m>-int-gpio integer, enables interrupts on a single
2287 MCP23S08 device on SPI<n>, CS#<m>, specifies
2288 the GPIO pin to which INT output of MCP23S08
2291 s17-spi<n>-<m>-int-gpio integer, enables mirrored interrupts on a
2292 single MCP23S17 device on SPI<n>, CS#<m>,
2293 specifies the GPIO pin to which either INTA
2294 or INTB output of MCP23S17 is connected.
2298 Info: Configures the MCP2515 CAN controller on spi0/1/2
2299 For devices on spi1 or spi2, the interfaces should be enabled
2300 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
2301 Load: dtoverlay=mcp2515,<param>=<val>
2302 Params: spi<n>-<m> Configure device at spi<n>, cs<m>
2305 oscillator Clock frequency for the CAN controller (Hz)
2307 speed Maximum SPI frequence (Hz)
2309 interrupt GPIO for interrupt signal
2313 Info: Configures the MCP2515 CAN controller on spi0.0
2314 Load: dtoverlay=mcp2515-can0,<param>=<val>
2315 Params: oscillator Clock frequency for the CAN controller (Hz)
2317 spimaxfrequency Maximum SPI frequence (Hz)
2319 interrupt GPIO for interrupt signal
2323 Info: Configures the MCP2515 CAN controller on spi0.1
2324 Load: dtoverlay=mcp2515-can1,<param>=<val>
2325 Params: oscillator Clock frequency for the CAN controller (Hz)
2327 spimaxfrequency Maximum SPI frequence (Hz)
2329 interrupt GPIO for interrupt signal
2333 Info: Configures the MCP251XFD CAN controller family
2334 For devices on spi1 or spi2, the interfaces should be enabled
2335 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
2336 Load: dtoverlay=mcp251xfd,<param>=<val>
2337 Params: spi<n>-<m> Configure device at spi<n>, cs<m>
2340 oscillator Clock frequency for the CAN controller (Hz)
2342 speed Maximum SPI frequence (Hz)
2344 interrupt GPIO for interrupt signal
2346 rx_interrupt GPIO for RX interrupt signal (nINT1) (optional)
2348 xceiver_enable GPIO for CAN transceiver enable (optional)
2350 xceiver_active_high specifiy if CAN transceiver enable pin is
2351 active high (optional, default: active low)
2355 Info: Configures MCP3008 A/D converters
2356 For devices on spi1 or spi2, the interfaces should be enabled
2357 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
2358 Load: dtoverlay=mcp3008,<param>[=<val>]
2359 Params: spi<n>-<m>-present boolean, configure device at spi<n>, cs<m>
2360 spi<n>-<m>-speed integer, set the spi bus speed for this device
2364 Info: Configures MCP3202 A/D converters
2365 For devices on spi1 or spi2, the interfaces should be enabled
2366 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
2367 Load: dtoverlay=mcp3202,<param>[=<val>]
2368 Params: spi<n>-<m>-present boolean, configure device at spi<n>, cs<m>
2369 spi<n>-<m>-speed integer, set the spi bus speed for this device
2373 Info: Overlay for activation of Microchip MCP3421-3428 ADCs over I2C
2374 Load: dtoverlay=mcp342x,<param>=<val>
2375 Params: addr I2C bus address of device, for devices with
2376 addresses that are configurable, e.g. by
2377 hardware links (default=0x68)
2378 mcp3421 The device is an MCP3421
2379 mcp3422 The device is an MCP3422
2380 mcp3423 The device is an MCP3423
2381 mcp3424 The device is an MCP3424
2382 mcp3425 The device is an MCP3425
2383 mcp3426 The device is an MCP3426
2384 mcp3427 The device is an MCP3427
2385 mcp3428 The device is an MCP3428
2389 Info: Media Center HAT - 2.83" Touch Display + extras by Pi Supply
2390 Load: dtoverlay=media-center,<param>=<val>
2391 Params: speed Display SPI bus speed
2392 rotate Display rotation {0,90,180,270}
2393 fps Delay between frame updates
2394 xohms Touchpanel sensitivity (X-plate resistance)
2395 swapxy Swap x and y axis
2396 backlight Change backlight GPIO pin {e.g. 12, 18}
2397 gpio_out_pin GPIO for output (default "17")
2398 gpio_in_pin GPIO for input (default "18")
2399 gpio_in_pull Pull up/down/off on the input pin
2401 sense Override the IR receive auto-detection logic:
2402 "0" = force active-high
2403 "1" = force active-low
2404 "-1" = use auto-detection
2406 softcarrier Turn the software carrier "on" or "off"
2408 invert "on" = invert the output pin (default "off")
2409 debug "on" = enable additional debug messages
2414 Info: Configures the merus-amp audio card
2415 Load: dtoverlay=merus-amp
2420 Info: Configures UART0 (ttyAMA0) so that a requested 38.4kbaud actually gets
2421 31.25kbaud, the frequency required for MIDI
2422 Load: dtoverlay=midi-uart0
2427 Info: Configures UART1 (ttyS0) so that a requested 38.4kbaud actually gets
2428 31.25kbaud, the frequency required for MIDI
2429 Load: dtoverlay=midi-uart1
2434 Info: Configures UART2 (ttyAMA1) so that a requested 38.4kbaud actually gets
2435 31.25kbaud, the frequency required for MIDI
2436 Load: dtoverlay=midi-uart2
2441 Info: Configures UART3 (ttyAMA2) so that a requested 38.4kbaud actually gets
2442 31.25kbaud, the frequency required for MIDI
2443 Load: dtoverlay=midi-uart3
2448 Info: Configures UART4 (ttyAMA3) so that a requested 38.4kbaud actually gets
2449 31.25kbaud, the frequency required for MIDI
2450 Load: dtoverlay=midi-uart4
2455 Info: Configures UART5 (ttyAMA4) so that a requested 38.4kbaud actually gets
2456 31.25kbaud, the frequency required for MIDI
2457 Load: dtoverlay=midi-uart5
2462 Info: Overlay for AdaFruit Mini Pi 1.3" TFT via SPI using fbtft driver.
2463 Load: dtoverlay=minipitft13,<param>=<val>
2464 Params: speed SPI bus speed (default 32000000)
2465 rotate Display rotation (0, 90, 180 or 270; default 0)
2466 width Display width (default 240)
2467 height Display height (default 240)
2468 fps Delay between frame updates (default 25)
2469 debug Debug output level (0-7; default 0)
2473 Info: Switch the onboard Bluetooth function on Pi 3B, 3B+, 3A+, 4B and Zero W
2474 to use the mini-UART (ttyS0) and restore UART0/ttyAMA0 over GPIOs 14 &
2475 15. Note that this may reduce the maximum usable baudrate.
2476 N.B. It is also necessary to edit /lib/systemd/system/hciuart.service
2477 and replace ttyAMA0 with ttyS0, unless using Raspbian or another
2478 distribution with udev rules that create /dev/serial0 and /dev/serial1,
2479 in which case use /dev/serial1 instead because it will always be
2480 correct. Furthermore, you must also set core_freq and core_freq_min to
2481 the same value in config.txt or the miniuart will not work.
2482 Load: dtoverlay=miniuart-bt,<param>=<val>
2483 Params: krnbt Set to "on" to enable autoprobing of Bluetooth
2484 driver without need of hciattach/btattach
2488 Info: Overlay for SPI-connected MIPI DBI displays using the panel-mipi-dbi
2489 driver. The driver will load a file /lib/firmware/panel.bin containing
2490 the initialisation commands.
2493 dtoverlay=mipi-dbi-spi,spi0-0,speed=70000000
2494 dtparam=width=320,height=240
2495 dtparam=reset-gpio=23,dc-gpio=24
2496 dtparam=backlight-gpio=18
2498 Compared to fbtft panel-mipi-dbi runs pixel data at spi-max-frequency
2499 and init commands at 10MHz. This makes it possible to push the envelope
2500 without messing up the controller configuration due to command
2501 transmission errors.
2503 For devices on spi1 or spi2, the interfaces should be enabled
2504 with one of the spi1-1/2/3cs and/or spi2-1/2/3cs overlays.
2506 See https://github.com/notro/panel-mipi-dbi/wiki for more info.
2508 Load: dtoverlay=mipi-dbi-spi,<param>=<val>
2510 compatible Set the compatible string to load a different
2511 firmware file. Both the panel compatible value
2512 used to load the firmware file and the value
2513 used to load the driver has to be set having a
2514 NUL (\0) separator between them.
2516 dtparam=compatible=mypanel\0panel-mipi-dbi-spi
2517 spi<n>-<m> Configure device at spi<n>, cs<m>
2519 speed SPI bus speed in Hz (default 32000000)
2520 cpha Shifted SPI clock phase (CPHA) mode
2521 cpol Inverse SPI clock polarity (CPOL) mode
2522 write-only Controller is not readable
2523 (ie. MISO is not wired up).
2525 width Panel width in pixels (required)
2526 height Panel height in pixels (required)
2527 width-mm Panel width in mm
2528 height-mm Panel height in mm
2529 x-offset Panel x-offset in controller RAM
2530 y-offset Panel y-offset in controller RAM
2532 clock-frequency Panel clock frequency in Hz
2533 (optional, just informational).
2535 reset-gpio GPIO pin to be used for RESET
2536 dc-gpio GPIO pin to be used for D/C
2538 backlight-gpio GPIO pin to be used for backlight control
2540 backlight-pwm PWM channel to be used for backlight control
2541 (default of none). NB Disables audio headphone
2542 output as that also uses PWM.
2543 backlight-pwm-chan Choose channel on &pwm node for backlight
2544 control (default 0).
2545 backlight-pwm-gpio GPIO pin to be used for the PWM backlight. See
2546 pwm-2chan for valid options (default 18).
2547 backlight-pwm-func Pin function of GPIO used for the PWM backlight.
2548 See pwm-2chan for valid options (default 2).
2549 backlight-def-brightness
2550 Set the default brightness. Normal range 1-16.
2555 Info: Overlay for i2c connected mlx90640 thermal camera
2556 Load: dtoverlay=mlx90640
2561 Info: Selects the bcm2835-mmc SD/MMC driver, optionally with overclock
2562 Load: dtoverlay=mmc,<param>=<val>
2563 Params: overclock_50 Clock (in MHz) to use when the MMC framework
2568 Info: Overlay for i2c connected mpu6050 imu
2569 Load: dtoverlay=mpu6050,<param>=<val>
2570 Params: interrupt GPIO pin for interrupt (default 4)
2571 addr I2C address of the device (default 0x68)
2575 Info: MZ61581 display by Tontec
2576 Load: dtoverlay=mz61581,<param>=<val>
2577 Params: speed Display SPI bus speed
2579 rotate Display rotation {0,90,180,270}
2581 fps Delay between frame updates
2583 txbuflen Transmit buffer length (default 32768)
2585 debug Debug output level {0-7}
2587 xohms Touchpanel sensitivity (X-plate resistance)
2591 Info: Omnivision OV2311 camera module.
2592 Uses Unicam 1, which is the standard camera connector on most Pi
2594 Load: dtoverlay=ov2311,<param>=<val>
2595 Params: rotation Mounting rotation of the camera sensor (0 or
2597 orientation Sensor orientation (0 = front, 1 = rear,
2598 2 = external, default external)
2599 media-controller Configure use of Media Controller API for
2600 configuring the sensor (default on)
2601 cam0 Adopt the default configuration for CAM0 on a
2602 Compute Module (CSI0, i2c_vc, and cam0_reg).
2606 Info: Omnivision OV5647 camera module.
2607 Uses Unicam 1, which is the standard camera connector on most Pi
2609 Load: dtoverlay=ov5647,<param>=<val>
2610 Params: rotation Mounting rotation of the camera sensor (0 or
2612 orientation Sensor orientation (0 = front, 1 = rear,
2613 2 = external, default external)
2614 media-controller Configure use of Media Controller API for
2615 configuring the sensor (default on)
2616 cam0 Adopt the default configuration for CAM0 on a
2617 Compute Module (CSI0, i2c_vc, and cam0_reg).
2618 vcm Configure a VCM focus drive on the sensor.
2622 Info: Omnivision OV7251 camera module.
2623 Uses Unicam 1, which is the standard camera connector on most Pi
2625 Load: dtoverlay=ov7251,<param>=<val>
2626 Params: rotation Mounting rotation of the camera sensor (0 or
2628 orientation Sensor orientation (0 = front, 1 = rear,
2629 2 = external, default external)
2630 media-controller Configure use of Media Controller API for
2631 configuring the sensor (default off)
2632 cam0 Adopt the default configuration for CAM0 on a
2633 Compute Module (CSI0, i2c_vc, and cam0_reg).
2637 Info: Omnivision OV9281 camera module.
2638 Uses Unicam 1, which is the standard camera connector on most Pi
2640 Load: dtoverlay=ov9281,<param>=<val>
2641 Params: rotation Mounting rotation of the camera sensor (0 or
2643 orientation Sensor orientation (0 = front, 1 = rear,
2644 2 = external, default external)
2645 media-controller Configure use of Media Controller API for
2646 configuring the sensor (default on)
2647 cam0 Adopt the default configuration for CAM0 on a
2648 Compute Module (CSI0, i2c_vc, and cam0_reg).
2652 Info: PaPiRus ePaper Screen by Pi Supply (both HAT and pHAT)
2653 Load: dtoverlay=papirus,<param>=<val>
2654 Params: panel Display panel (required):
2659 speed Display SPI bus speed
2663 Info: TI PCA953x family of I2C GPIO expanders. Default is for NXP PCA9534.
2664 Load: dtoverlay=pca953x,<param>=<val>
2665 Params: addr I2C address of expander. Default 0x20.
2666 pca6416 Select the NXP PCA6416 (16 bit)
2667 pca9505 Select the NXP PCA9505 (40 bit)
2668 pca9535 Select the NXP PCA9535 (16 bit)
2669 pca9536 Select the NXP PCA9536 or TI PCA9536 (4 bit)
2670 pca9537 Select the NXP PCA9537 (4 bit)
2671 pca9538 Select the NXP PCA9538 (8 bit)
2672 pca9539 Select the NXP PCA9539 (16 bit)
2673 pca9554 Select the NXP PCA9554 (8 bit)
2674 pca9555 Select the NXP PCA9555 (16 bit)
2675 pca9556 Select the NXP PCA9556 (8 bit)
2676 pca9557 Select the NXP PCA9557 (8 bit)
2677 pca9574 Select the NXP PCA9574 (8 bit)
2678 pca9575 Select the NXP PCA9575 (16 bit)
2679 pca9698 Select the NXP PCA9698 (40 bit)
2680 pca16416 Select the NXP PCA16416 (16 bit)
2681 pca16524 Select the NXP PCA16524 (24 bit)
2682 pca19555a Select the NXP PCA19555A (16 bit)
2683 max7310 Select the Maxim MAX7310 (8 bit)
2684 max7312 Select the Maxim MAX7312 (16 bit)
2685 max7313 Select the Maxim MAX7313 (16 bit)
2686 max7315 Select the Maxim MAX7315 (8 bit)
2687 pca6107 Select the TI PCA6107 (8 bit)
2688 tca6408 Select the TI TCA6408 (8 bit)
2689 tca6416 Select the TI TCA6416 (16 bit)
2690 tca6424 Select the TI TCA6424 (24 bit)
2691 tca9539 Select the TI TCA9539 (16 bit)
2692 tca9554 Select the TI TCA9554 (8 bit)
2693 cat9554 Select the Onnn CAT9554 (8 bit)
2694 pca9654 Select the Onnn PCA9654 (8 bit)
2695 xra1202 Select the Exar XRA1202 (8 bit)
2698 Name: pcie-32bit-dma
2699 Info: Force PCIe config to support 32bit DMA addresses at the expense of
2700 having to bounce buffers.
2701 Load: dtoverlay=pcie-32bit-dma
2705 [ The pcf2127-rtc overlay has been deleted. See i2c-rtc. ]
2708 [ The pcf8523-rtc overlay has been deleted. See i2c-rtc. ]
2711 [ The pcf8563-rtc overlay has been deleted. See i2c-rtc. ]
2715 Info: This overlay has been renamed act-led, keeping pi3-act-led as an alias
2716 for backwards compatibility.
2720 Name: pi3-disable-bt
2721 Info: This overlay has been renamed disable-bt, keeping pi3-disable-bt as an
2722 alias for backwards compatibility.
2726 Name: pi3-disable-wifi
2727 Info: This overlay has been renamed disable-wifi, keeping pi3-disable-wifi as
2728 an alias for backwards compatibility.
2732 Name: pi3-miniuart-bt
2733 Info: This overlay has been renamed miniuart-bt, keeping pi3-miniuart-bt as
2734 an alias for backwards compatibility.
2739 Info: Configures the pibell audio card.
2740 Load: dtoverlay=pibell,<param>=<val>
2741 Params: alsaname Set the name as it appears in ALSA (default
2746 Info: Configures the PiFace Digital mcp23s17 GPIO port expander.
2747 Load: dtoverlay=pifacedigital,<param>=<val>
2748 Params: spi-present-mask 8-bit integer, bitmap indicating MCP23S17 SPI0
2749 CS0 address. PiFace Digital supports addresses
2750 0-3, which can be configured with JP1 and JP2.
2754 Info: Configures the PiFi 40W stereo amplifier
2755 Load: dtoverlay=pifi-40
2760 Info: Configures the PiFi DAC HD
2761 Load: dtoverlay=pifi-dac-hd
2766 Info: Configures the PiFi DAC Zero
2767 Load: dtoverlay=pifi-dac-zero
2772 Info: Configures the PiFi Mini stereo amplifier
2773 Load: dtoverlay=pifi-mini-210
2778 Info: Configures the PiGlow by pimoroni.com
2779 Load: dtoverlay=piglow
2784 Info: PiScreen display by OzzMaker.com
2785 Load: dtoverlay=piscreen,<param>=<val>
2786 Params: speed Display SPI bus speed
2788 rotate Display rotation {0,90,180,270}
2790 fps Delay between frame updates
2792 debug Debug output level {0-7}
2794 xohms Touchpanel sensitivity (X-plate resistance)
2798 Info: PiScreen 2 with resistive TP display by OzzMaker.com
2799 Load: dtoverlay=piscreen2r,<param>=<val>
2800 Params: speed Display SPI bus speed
2802 rotate Display rotation {0,90,180,270}
2804 fps Delay between frame updates
2806 debug Debug output level {0-7}
2808 xohms Touchpanel sensitivity (X-plate resistance)
2812 Info: Configures the Blokas Labs pisound card
2813 Load: dtoverlay=pisound
2818 Info: Adafruit PiTFT 2.2" screen
2819 Load: dtoverlay=pitft22,<param>=<val>
2820 Params: speed Display SPI bus speed
2822 rotate Display rotation {0,90,180,270}
2824 fps Delay between frame updates
2826 debug Debug output level {0-7}
2829 Name: pitft28-capacitive
2830 Info: Adafruit PiTFT 2.8" capacitive touch screen
2831 Load: dtoverlay=pitft28-capacitive,<param>=<val>
2832 Params: speed Display SPI bus speed
2834 rotate Display rotation {0,90,180,270}
2836 fps Delay between frame updates
2838 debug Debug output level {0-7}
2840 touch-sizex Touchscreen size x (default 240)
2842 touch-sizey Touchscreen size y (default 320)
2844 touch-invx Touchscreen inverted x axis
2846 touch-invy Touchscreen inverted y axis
2848 touch-swapxy Touchscreen swapped x y axis
2851 Name: pitft28-resistive
2852 Info: Adafruit PiTFT 2.8" resistive touch screen
2853 Load: dtoverlay=pitft28-resistive,<param>=<val>
2854 Params: speed Display SPI bus speed
2856 rotate Display rotation {0,90,180,270}
2858 fps Delay between frame updates
2860 debug Debug output level {0-7}
2862 drm Force the use of the mi0283qt DRM driver (by
2863 default the ili9340 framebuffer driver will
2864 be used in preference if available)
2867 Name: pitft35-resistive
2868 Info: Adafruit PiTFT 3.5" resistive touch screen
2869 Load: dtoverlay=pitft35-resistive,<param>=<val>
2870 Params: speed Display SPI bus speed
2872 rotate Display rotation {0,90,180,270}
2874 fps Delay between frame updates
2876 debug Debug output level {0-7}
2878 drm Force the use of the hx8357d DRM driver (by
2879 default the fb_hx8357d framebuffer driver will
2880 be used in preference if available)
2884 Info: Configures the pps-gpio (pulse-per-second time signal via GPIO).
2885 Load: dtoverlay=pps-gpio,<param>=<val>
2886 Params: gpiopin Input GPIO (default "18")
2887 assert_falling_edge When present, assert is indicated by a falling
2888 edge, rather than by a rising edge (default
2890 capture_clear Generate clear events on the trailing edge
2895 Info: Configures a single PWM channel
2896 Legal pin,function combinations for each channel:
2897 PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
2898 PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
2900 1) Pin 18 is the only one available on all platforms, and
2901 it is the one used by the I2S audio interface.
2902 Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
2903 2) The onboard analogue audio output uses both PWM channels.
2904 3) So be careful mixing audio and PWM.
2905 4) Currently the clock must have been enabled and configured
2907 Load: dtoverlay=pwm,<param>=<val>
2908 Params: pin Output pin (default 18) - see table
2909 func Pin function (default 2 = Alt5) - see above
2910 clock PWM clock frequency (informational)
2914 Info: Configures both PWM channels
2915 Legal pin,function combinations for each channel:
2916 PWM0: 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
2917 PWM1: 13,4(Alt0) 19,2(Alt5) 41,4(Alt0) 45,4(Alt0) 53,5(Alt1)
2919 1) Pin 18 is the only one available on all platforms, and
2920 it is the one used by the I2S audio interface.
2921 Pins 12 and 13 might be better choices on an A+, B+ or Pi2.
2922 2) The onboard analogue audio output uses both PWM channels.
2923 3) So be careful mixing audio and PWM.
2924 4) Currently the clock must have been enabled and configured
2926 Load: dtoverlay=pwm-2chan,<param>=<val>
2927 Params: pin Output pin (default 18) - see table
2928 pin2 Output pin for other channel (default 19)
2929 func Pin function (default 2 = Alt5) - see above
2930 func2 Function for pin2 (default 2 = Alt5)
2931 clock PWM clock frequency (informational)
2935 Info: Use GPIO pin as pwm-assisted infrared transmitter output.
2936 This is an alternative to "gpio-ir-tx". pwm-ir-tx makes use
2937 of PWM0 to reduce the CPU load during transmission compared to
2938 gpio-ir-tx which uses bit-banging.
2939 Legal pin,function combinations are:
2940 12,4(Alt0) 18,2(Alt5) 40,4(Alt0) 52,5(Alt1)
2941 Load: dtoverlay=pwm-ir-tx,<param>=<val>
2942 Params: gpio_pin Output GPIO (default 18)
2944 func Pin function (default 2 = Alt5)
2948 Info: in-tech's Evaluation Board for PLC Stamp micro
2949 This uses spi0 and a separate GPIO interrupt to connect the QCA7000.
2950 Load: dtoverlay=qca7000,<param>=<val>
2951 Params: int_pin GPIO pin for interrupt signal (default 23)
2953 speed SPI bus speed (default 12 MHz)
2957 Info: in-tech's Evaluation Board for PLC Stamp micro (UART)
2958 This uses uart0/ttyAMA0 over GPIOs 14 & 15 to connect the QCA7000.
2959 But it requires disabling of onboard Bluetooth on
2960 Pi 3B, 3B+, 3A+, 4B and Zero W.
2961 Load: dtoverlay=qca7000-uart0,<param>=<val>
2962 Params: baudrate Set the baudrate for the UART (default
2966 Name: rotary-encoder
2967 Info: Overlay for GPIO connected rotary encoder.
2968 Load: dtoverlay=rotary-encoder,<param>=<val>
2969 Params: pin_a GPIO connected to rotary encoder channel A
2971 pin_b GPIO connected to rotary encoder channel B
2973 relative_axis register a relative axis rather than an
2974 absolute one. Relative axis will only
2975 generate +1/-1 events on the input device,
2976 hence no steps need to be passed.
2977 linux_axis the input subsystem axis to map to this
2978 rotary encoder. Defaults to 0 (ABS_X / REL_X)
2979 rollover Automatic rollover when the rotary value
2980 becomes greater than the specified steps or
2981 smaller than 0. For absolute axis only.
2982 steps-per-period Number of steps (stable states) per period.
2983 The values have the following meaning:
2984 1: Full-period mode (default)
2986 4: Quarter-period mode
2987 steps Number of steps in a full turnaround of the
2988 encoder. Only relevant for absolute axis.
2989 Defaults to 24 which is a typical value for
2991 wakeup Boolean, rotary encoder can wake up the
2993 encoding String, the method used to encode steps.
2994 Supported are "gray" (the default and more
2995 common) and "binary".
2999 Info: Raspberry Pi official display backlight driver
3000 Load: dtoverlay=rpi-backlight
3004 Name: rpi-cirrus-wm5102
3005 Info: Configures the Cirrus Logic Audio Card
3006 Load: dtoverlay=rpi-cirrus-wm5102
3011 Info: Configures the RPi DAC audio card
3012 Load: dtoverlay=rpi-dac
3017 Info: RPi-Display - 2.8" Touch Display by Watterott
3018 Linux has 2 drivers that support this display and this overlay supports
3022 fbtft/fb_ili9341: dtoverlay=rpi-display
3023 drm/mi0283qt: dtoverlay=rpi-display,drm,backlight-pwm,rotate=180
3025 Some notable differences with the DRM driver compared to fbtft:
3026 - The display is turned on when it's first used and not on driver load
3027 as with fbtft. So if nothing uses the display it stays off.
3028 - Can run with a higher SPI clock increasing framerate. This is possible
3029 since the driver avoids messing up the controller configuration due to
3030 transmission errors by running config commands at 10MHz and only pixel
3031 data at full speed (occasional pixel glitch might occur).
3032 - PWM backlight is supported.
3034 Load: dtoverlay=rpi-display,<param>=<val>
3035 Params: speed Display SPI bus speed
3036 rotate Display rotation {0,90,180,270}
3037 fps Delay between frame updates (fbtft only)
3038 debug Debug output level {0-7} (fbtft only)
3039 xohms Touchpanel sensitivity (X-plate resistance)
3040 swapxy Swap x and y axis
3041 backlight Change backlight GPIO pin {e.g. 12, 18}
3043 drm Use DRM/KMS driver mi0283qt instead of fbtft.
3044 Set the SPI clock to 70MHz.
3045 This has to be the first parameter.
3046 backlight-pwm Use pwm for backlight (drm only). NB: Disables
3047 audio headphone output as that also uses PWM.
3051 Info: Official Raspberry Pi display touchscreen
3052 Load: dtoverlay=rpi-ft5406,<param>=<val>
3053 Params: touchscreen-size-x Touchscreen X resolution (default 800)
3054 touchscreen-size-y Touchscreen Y resolution (default 600);
3055 touchscreen-inverted-x Invert touchscreen X coordinates (default 0);
3056 touchscreen-inverted-y Invert touchscreen Y coordinates (default 0);
3057 touchscreen-swapped-x-y Swap X and Y cordinates (default 0);
3061 Info: Raspberry Pi PoE HAT fan
3062 Load: dtoverlay=rpi-poe,<param>[=<val>]
3063 Params: poe_fan_temp0 Temperature (in millicelcius) at which the fan
3064 turns on (default 40000)
3065 poe_fan_temp0_hyst Temperature delta (in millicelcius) at which
3066 the fan turns off (default 2000)
3067 poe_fan_temp1 Temperature (in millicelcius) at which the fan
3068 speeds up (default 45000)
3069 poe_fan_temp1_hyst Temperature delta (in millicelcius) at which
3070 the fan slows down (default 2000)
3071 poe_fan_temp2 Temperature (in millicelcius) at which the fan
3072 speeds up (default 50000)
3073 poe_fan_temp2_hyst Temperature delta (in millicelcius) at which
3074 the fan slows down (default 2000)
3075 poe_fan_temp3 Temperature (in millicelcius) at which the fan
3076 speeds up (default 55000)
3077 poe_fan_temp3_hyst Temperature delta (in millicelcius) at which
3078 the fan slows down (default 5000)
3079 i2c Control the fan via Linux I2C drivers instead of
3084 Info: Raspberry Pi PoE+ HAT fan
3085 Load: dtoverlay=rpi-poe-plus,<param>[=<val>]
3086 Params: poe_fan_temp0 Temperature (in millicelcius) at which the fan
3087 turns on (default 40000)
3088 poe_fan_temp0_hyst Temperature delta (in millicelcius) at which
3089 the fan turns off (default 2000)
3090 poe_fan_temp1 Temperature (in millicelcius) at which the fan
3091 speeds up (default 45000)
3092 poe_fan_temp1_hyst Temperature delta (in millicelcius) at which
3093 the fan slows down (default 2000)
3094 poe_fan_temp2 Temperature (in millicelcius) at which the fan
3095 speeds up (default 50000)
3096 poe_fan_temp2_hyst Temperature delta (in millicelcius) at which
3097 the fan slows down (default 2000)
3098 poe_fan_temp3 Temperature (in millicelcius) at which the fan
3099 speeds up (default 55000)
3100 poe_fan_temp3_hyst Temperature delta (in millicelcius) at which
3101 the fan slows down (default 5000)
3102 i2c Control the fan via Linux I2C drivers instead of
3107 Info: Configures the RPi Proto audio card
3108 Load: dtoverlay=rpi-proto
3113 Info: Raspberry Pi Sense HAT
3114 Load: dtoverlay=rpi-sense
3119 Info: Raspberry Pi TV HAT
3120 Load: dtoverlay=rpi-tv
3125 Info: Load the V4L2 stateless video decoder driver for the HEVC block,
3126 disabling the memory mapped devices in the process.
3127 Load: dtoverlay=rpivid-v4l2
3131 Name: rra-digidac1-wm8741-audio
3132 Info: Configures the Red Rocks Audio DigiDAC1 soundcard
3133 Load: dtoverlay=rra-digidac1-wm8741-audio
3138 Info: Overlay for the SPI-connected Sainsmart 1.8" display (based on the
3140 Load: dtoverlay=sainsmart18,<param>=<val>
3141 Params: rotate Display rotation {0,90,180,270}
3142 speed SPI bus speed in Hz (default 4000000)
3143 fps Display frame rate in Hz
3144 bgr Enable BGR mode (default off)
3145 debug Debug output level {0-7}
3146 dc_pin GPIO pin for D/C (default 24)
3147 reset_pin GPIO pin for RESET (default 25)
3151 Info: Overlay for the NXP SC16IS750 UART with I2C Interface
3152 Enables the chip on I2C1 at 0x48 (or the "addr" parameter value). To
3153 select another address, please refer to table 10 in reference manual.
3154 Load: dtoverlay=sc16is750-i2c,<param>=<val>
3155 Params: int_pin GPIO used for IRQ (default 24)
3156 addr Address (default 0x48)
3157 xtal On-board crystal frequency (default 14745600)
3161 Info: Overlay for the NXP SC16IS752 dual UART with I2C Interface
3162 Enables the chip on I2C1 at 0x48 (or the "addr" parameter value). To
3163 select another address, please refer to table 10 in reference manual.
3164 Load: dtoverlay=sc16is752-i2c,<param>=<val>
3165 Params: int_pin GPIO used for IRQ (default 24)
3166 addr Address (default 0x48)
3167 xtal On-board crystal frequency (default 14745600)
3170 Name: sc16is752-spi0
3171 Info: Overlay for the NXP SC16IS752 Dual UART with SPI Interface
3172 Enables the chip on SPI0.
3173 Load: dtoverlay=sc16is752-spi0,<param>=<val>
3174 Params: int_pin GPIO used for IRQ (default 24)
3175 xtal On-board crystal frequency (default 14745600)
3178 Name: sc16is752-spi1
3179 Info: Overlay for the NXP SC16IS752 Dual UART with SPI Interface
3180 Enables the chip on SPI1.
3181 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
3182 A+, B+, Zero and PI2 B; as well as the Compute Module.
3184 Load: dtoverlay=sc16is752-spi1,<param>=<val>
3185 Params: int_pin GPIO used for IRQ (default 24)
3186 xtal On-board crystal frequency (default 14745600)
3190 Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock.
3191 N.B. This overlay is designed for situations where the mmc driver is
3192 the default, so it disables the other (mmc) interface - this will kill
3193 WLAN on a Pi3. If this isn't what you want, either use the sdtweak
3194 overlay or the new sd_* dtparams of the base DTBs.
3195 Load: dtoverlay=sdhost,<param>=<val>
3196 Params: overclock_50 Clock (in MHz) to use when the MMC framework
3199 force_pio Disable DMA support (default off)
3201 pio_limit Number of blocks above which to use DMA
3204 debug Enable debug output (default off)
3208 Info: Selects the bcm2835-sdhost SD/MMC driver, optionally with overclock,
3209 and enables SDIO via GPIOs 22-27. An example of use in 1-bit mode is
3210 "dtoverlay=sdio,bus_width=1,gpios_22_25"
3211 Load: dtoverlay=sdio,<param>=<val>
3212 Params: sdio_overclock SDIO Clock (in MHz) to use when the MMC
3213 framework requests 50MHz
3215 poll_once Disable SDIO-device polling every second
3216 (default on: polling once at boot-time)
3218 bus_width Set the SDIO host bus width (default 4 bits)
3220 gpios_22_25 Select GPIOs 22-25 for 1-bit mode. Must be used
3221 with bus_width=1. This replaces the sdio-1bit
3222 overlay, which is now deprecated.
3224 gpios_34_37 Select GPIOs 34-37 for 1-bit mode. Must be used
3227 gpios_34_39 Select GPIOs 34-39 for 4-bit mode. Must be used
3228 with bus_width=4 (the default).
3232 Info: This overlay is now deprecated. Use
3233 "dtoverlay=sdio,bus_width=1,gpios_22_25" instead.
3238 Info: This overlay is now deprecated. Use the sd_* dtparams in the
3239 base DTB, e.g. "dtoverlay=sdtweak,poll_once" becomes
3240 "dtparam=sd_poll_once".
3244 Name: seeed-can-fd-hat-v1
3245 Info: Overlay for Seeed Studio CAN BUS FD HAT with two CAN FD
3246 channels without RTC. Use this overlay if your HAT has no
3248 https://www.seeedstudio.com/2-Channel-CAN-BUS-FD-Shield-for-Raspberry-Pi-p-4072.html
3249 Load: dtoverlay=seeed-can-fd-hat-v1
3253 Name: seeed-can-fd-hat-v2
3254 Info: Overlay for Seeed Studio CAN BUS FD HAT with two CAN FD
3255 channels and an RTC. Use this overlay if your HAT has a
3257 https://www.seeedstudio.com/CAN-BUS-FD-HAT-for-Raspberry-Pi-p-4742.html
3258 Load: dtoverlay=seeed-can-fd-hat-v2
3263 Info: Overlay for SH1106 OLED via SPI using fbtft staging driver.
3264 Load: dtoverlay=sh1106-spi,<param>=<val>
3265 Params: speed SPI bus speed (default 4000000)
3266 rotate Display rotation (0, 90, 180 or 270; default 0)
3267 fps Delay between frame updates (default 25)
3268 debug Debug output level (0-7; default 0)
3269 dc_pin GPIO pin for D/C (default 24)
3270 reset_pin GPIO pin for RESET (default 25)
3271 height Display height (32 or 64; default 64)
3275 Info: Overlay for Si446x UHF Transceiver via SPI using si446x driver.
3276 The driver is currently out-of-tree at
3277 https://github.com/sunipkmukherjee/silabs.git
3278 Load: dtoverlay=si446x-spi0,<param>=<val>
3279 Params: speed SPI bus speed (default 4000000)
3280 int_pin GPIO pin for interrupts (default 17)
3281 reset_pin GPIO pin for RESET (default 27)
3285 Info: Enables the Secondary Memory Interface peripheral. Uses GPIOs 2-25!
3291 Info: Enables the userspace interface for the SMI driver
3292 Load: dtoverlay=smi-dev
3297 Info: Enables access to NAND flash via the SMI interface
3298 Load: dtoverlay=smi-nand
3303 Info: Move SPI function block to GPIO 35 to 39
3304 Load: dtoverlay=spi-gpio35-39
3309 Info: Move SPI function block to GPIOs 40 to 45
3310 Load: dtoverlay=spi-gpio40-45
3315 Info: Adds support for a number of SPI Real Time Clock devices
3316 Load: dtoverlay=spi-rtc,<param>=<val>
3317 Params: ds3232 Select the DS3232 device
3318 ds3234 Select the DS3234 device
3319 pcf2123 Select the PCF2123 device
3321 spi0_0 Use spi0.0 (default)
3327 cs_high This device requires an active-high CS
3331 Info: Don't claim any CS pins for SPI0. Requires a device with its chip
3332 select permanently enabled, but frees a GPIO for e.g. a DPI display.
3333 Load: dtoverlay=spi0-0cs,<param>=<val>
3334 Params: no_miso Don't claim and use the MISO pin (9), freeing
3339 Info: Only use one CS pin for SPI0
3340 Load: dtoverlay=spi0-1cs,<param>=<val>
3341 Params: cs0_pin GPIO pin for CS0 (default 8)
3342 no_miso Don't claim and use the MISO pin (9), freeing
3347 Info: Change the CS pins for SPI0
3348 Load: dtoverlay=spi0-2cs,<param>=<val>
3349 Params: cs0_pin GPIO pin for CS0 (default 8)
3350 cs1_pin GPIO pin for CS1 (default 7)
3351 no_miso Don't claim and use the MISO pin (9), freeing
3356 Info: This overlay has been renamed spi0-2cs, keeping spi0-cs as an
3357 alias for backwards compatibility.
3362 Info: This overlay has been deprecated and removed because it is no longer
3363 necessary and has been seen to prevent spi0 from working.
3368 Info: Enables spi1 with a single chip select (CS) line and associated spidev
3369 dev node. The gpio pin number for the CS line and spidev device node
3370 creation are configurable.
3371 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
3372 A+, B+, Zero and PI2 B; as well as the Compute Module.
3373 Load: dtoverlay=spi1-1cs,<param>=<val>
3374 Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
3375 cs0_spidev Set to 'disabled' to stop the creation of a
3376 userspace device node /dev/spidev1.0 (default
3377 is 'okay' or enabled).
3381 Info: Enables spi1 with two chip select (CS) lines and associated spidev
3382 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3383 creation are configurable.
3384 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
3385 A+, B+, Zero and PI2 B; as well as the Compute Module.
3386 Load: dtoverlay=spi1-2cs,<param>=<val>
3387 Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
3388 cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1).
3389 cs0_spidev Set to 'disabled' to stop the creation of a
3390 userspace device node /dev/spidev1.0 (default
3391 is 'okay' or enabled).
3392 cs1_spidev Set to 'disabled' to stop the creation of a
3393 userspace device node /dev/spidev1.1 (default
3394 is 'okay' or enabled).
3398 Info: Enables spi1 with three chip select (CS) lines and associated spidev
3399 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3400 creation are configurable.
3401 N.B.: spi1 is only accessible on devices with a 40pin header, eg:
3402 A+, B+, Zero and PI2 B; as well as the Compute Module.
3403 Load: dtoverlay=spi1-3cs,<param>=<val>
3404 Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI1_CE0).
3405 cs1_pin GPIO pin for CS1 (default 17 - BCM SPI1_CE1).
3406 cs2_pin GPIO pin for CS2 (default 16 - BCM SPI1_CE2).
3407 cs0_spidev Set to 'disabled' to stop the creation of a
3408 userspace device node /dev/spidev1.0 (default
3409 is 'okay' or enabled).
3410 cs1_spidev Set to 'disabled' to stop the creation of a
3411 userspace device node /dev/spidev1.1 (default
3412 is 'okay' or enabled).
3413 cs2_spidev Set to 'disabled' to stop the creation of a
3414 userspace device node /dev/spidev1.2 (default
3415 is 'okay' or enabled).
3419 Info: Enables spi2 with a single chip select (CS) line and associated spidev
3420 dev node. The gpio pin number for the CS line and spidev device node
3421 creation are configurable.
3422 N.B.: spi2 is only accessible with the Compute Module.
3423 Load: dtoverlay=spi2-1cs,<param>=<val>
3424 Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
3425 cs0_spidev Set to 'disabled' to stop the creation of a
3426 userspace device node /dev/spidev2.0 (default
3427 is 'okay' or enabled).
3431 Info: Enables spi2 with two chip select (CS) lines and associated spidev
3432 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3433 creation are configurable.
3434 N.B.: spi2 is only accessible with the Compute Module.
3435 Load: dtoverlay=spi2-2cs,<param>=<val>
3436 Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
3437 cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1).
3438 cs0_spidev Set to 'disabled' to stop the creation of a
3439 userspace device node /dev/spidev2.0 (default
3440 is 'okay' or enabled).
3441 cs1_spidev Set to 'disabled' to stop the creation of a
3442 userspace device node /dev/spidev2.1 (default
3443 is 'okay' or enabled).
3447 Info: Enables spi2 with three chip select (CS) lines and associated spidev
3448 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3449 creation are configurable.
3450 N.B.: spi2 is only accessible with the Compute Module.
3451 Load: dtoverlay=spi2-3cs,<param>=<val>
3452 Params: cs0_pin GPIO pin for CS0 (default 43 - BCM SPI2_CE0).
3453 cs1_pin GPIO pin for CS1 (default 44 - BCM SPI2_CE1).
3454 cs2_pin GPIO pin for CS2 (default 45 - BCM SPI2_CE2).
3455 cs0_spidev Set to 'disabled' to stop the creation of a
3456 userspace device node /dev/spidev2.0 (default
3457 is 'okay' or enabled).
3458 cs1_spidev Set to 'disabled' to stop the creation of a
3459 userspace device node /dev/spidev2.1 (default
3460 is 'okay' or enabled).
3461 cs2_spidev Set to 'disabled' to stop the creation of a
3462 userspace device node /dev/spidev2.2 (default
3463 is 'okay' or enabled).
3467 Info: Enables spi3 with a single chip select (CS) line and associated spidev
3468 dev node. The gpio pin number for the CS line and spidev device node
3469 creation are configurable. BCM2711 only.
3470 Load: dtoverlay=spi3-1cs,<param>=<val>
3471 Params: cs0_pin GPIO pin for CS0 (default 0 - BCM SPI3_CE0).
3472 cs0_spidev Set to 'off' to prevent the creation of a
3473 userspace device node /dev/spidev3.0 (default
3474 is 'on' or enabled).
3478 Info: Enables spi3 with two chip select (CS) lines and associated spidev
3479 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3480 creation are configurable. BCM2711 only.
3481 Load: dtoverlay=spi3-2cs,<param>=<val>
3482 Params: cs0_pin GPIO pin for CS0 (default 0 - BCM SPI3_CE0).
3483 cs1_pin GPIO pin for CS1 (default 24 - BCM SPI3_CE1).
3484 cs0_spidev Set to 'off' to prevent the creation of a
3485 userspace device node /dev/spidev3.0 (default
3486 is 'on' or enabled).
3487 cs1_spidev Set to 'off' to prevent the creation of a
3488 userspace device node /dev/spidev3.1 (default
3489 is 'on' or enabled).
3493 Info: Enables spi4 with a single chip select (CS) line and associated spidev
3494 dev node. The gpio pin number for the CS line and spidev device node
3495 creation are configurable. BCM2711 only.
3496 Load: dtoverlay=spi4-1cs,<param>=<val>
3497 Params: cs0_pin GPIO pin for CS0 (default 4 - BCM SPI4_CE0).
3498 cs0_spidev Set to 'off' to prevent the creation of a
3499 userspace device node /dev/spidev4.0 (default
3500 is 'on' or enabled).
3504 Info: Enables spi4 with two chip select (CS) lines and associated spidev
3505 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3506 creation are configurable. BCM2711 only.
3507 Load: dtoverlay=spi4-2cs,<param>=<val>
3508 Params: cs0_pin GPIO pin for CS0 (default 4 - BCM SPI4_CE0).
3509 cs1_pin GPIO pin for CS1 (default 25 - BCM SPI4_CE1).
3510 cs0_spidev Set to 'off' to prevent the creation of a
3511 userspace device node /dev/spidev4.0 (default
3512 is 'on' or enabled).
3513 cs1_spidev Set to 'off' to prevent the creation of a
3514 userspace device node /dev/spidev4.1 (default
3515 is 'on' or enabled).
3519 Info: Enables spi5 with a single chip select (CS) line and associated spidev
3520 dev node. The gpio pin numbers for the CS lines and spidev device node
3521 creation are configurable. BCM2711 only.
3522 Load: dtoverlay=spi5-1cs,<param>=<val>
3523 Params: cs0_pin GPIO pin for CS0 (default 12 - BCM SPI5_CE0).
3524 cs0_spidev Set to 'off' to prevent the creation of a
3525 userspace device node /dev/spidev5.0 (default
3526 is 'on' or enabled).
3530 Info: Enables spi5 with two chip select (CS) lines and associated spidev
3531 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3532 creation are configurable. BCM2711 only.
3533 Load: dtoverlay=spi5-2cs,<param>=<val>
3534 Params: cs0_pin GPIO pin for CS0 (default 12 - BCM SPI5_CE0).
3535 cs1_pin GPIO pin for CS1 (default 26 - BCM SPI5_CE1).
3536 cs0_spidev Set to 'off' to prevent the creation of a
3537 userspace device node /dev/spidev5.0 (default
3538 is 'on' or enabled).
3539 cs1_spidev Set to 'off' to prevent the creation of a
3540 userspace device node /dev/spidev5.1 (default
3541 is 'on' or enabled).
3545 Info: Enables spi6 with a single chip select (CS) line and associated spidev
3546 dev node. The gpio pin number for the CS line and spidev device node
3547 creation are configurable. BCM2711 only.
3548 Load: dtoverlay=spi6-1cs,<param>=<val>
3549 Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI6_CE0).
3550 cs0_spidev Set to 'off' to prevent the creation of a
3551 userspace device node /dev/spidev6.0 (default
3552 is 'on' or enabled).
3556 Info: Enables spi6 with two chip select (CS) lines and associated spidev
3557 dev nodes. The gpio pin numbers for the CS lines and spidev device node
3558 creation are configurable. BCM2711 only.
3559 Load: dtoverlay=spi6-2cs,<param>=<val>
3560 Params: cs0_pin GPIO pin for CS0 (default 18 - BCM SPI6_CE0).
3561 cs1_pin GPIO pin for CS1 (default 27 - BCM SPI6_CE1).
3562 cs0_spidev Set to 'off' to prevent the creation of a
3563 userspace device node /dev/spidev6.0 (default
3564 is 'on' or enabled).
3565 cs1_spidev Set to 'off' to prevent the creation of a
3566 userspace device node /dev/spidev6.1 (default
3567 is 'on' or enabled).
3571 Info: Overlay for activation of SSD1306 over I2C OLED display framebuffer.
3572 Load: dtoverlay=ssd1306,<param>=<val>
3573 Params: address Location in display memory of first character.
3575 width Width of display. (default=128)
3576 height Height of display. (default=64)
3577 offset virtual channel a. (default=0)
3578 normal Has no effect on displays tested. (default=not
3580 sequential Set this if every other scan line is missing.
3582 remapped Set this if display is garbled. (default=not
3584 inverted Set this if display is inverted and mirrored.
3588 Typical usage for 128x64 display: dtoverlay=ssd1306,inverted
3590 Typical usage for 128x32 display: dtoverlay=ssd1306,inverted,sequential
3592 i2c_baudrate=400000 will speed up the display.
3594 i2c_baudrate=1000000 seems to work even though it's not officially
3595 supported by the hardware, and is faster still.
3597 For more information refer to the device datasheet at:
3598 https://cdn-shop.adafruit.com/datasheets/SSD1306.pdf
3602 Info: Overlay for SSD1306 OLED via SPI using fbtft staging driver.
3603 Load: dtoverlay=ssd1306-spi,<param>=<val>
3604 Params: speed SPI bus speed (default 10000000)
3605 rotate Display rotation (0, 90, 180 or 270; default 0)
3606 fps Delay between frame updates (default 25)
3607 debug Debug output level (0-7; default 0)
3608 dc_pin GPIO pin for D/C (default 24)
3609 reset_pin GPIO pin for RESET (default 25)
3610 height Display height (32 or 64; default 64)
3614 Info: Overlay for SSD1331 OLED via SPI using fbtft staging driver.
3615 Load: dtoverlay=ssd1331-spi,<param>=<val>
3616 Params: speed SPI bus speed (default 4500000)
3617 rotate Display rotation (0, 90, 180 or 270; default 0)
3618 fps Delay between frame updates (default 25)
3619 debug Debug output level (0-7; default 0)
3620 dc_pin GPIO pin for D/C (default 24)
3621 reset_pin GPIO pin for RESET (default 25)
3625 Info: Overlay for SSD1351 OLED via SPI using fbtft staging driver.
3626 Load: dtoverlay=ssd1351-spi,<param>=<val>
3627 Params: speed SPI bus speed (default 4500000)
3628 rotate Display rotation (0, 90, 180 or 270; default 0)
3629 fps Delay between frame updates (default 25)
3630 debug Debug output level (0-7; default 0)
3631 dc_pin GPIO pin for D/C (default 24)
3632 reset_pin GPIO pin for RESET (default 25)
3635 Name: superaudioboard
3636 Info: Configures the SuperAudioBoard sound card
3637 Load: dtoverlay=superaudioboard,<param>=<val>
3638 Params: gpiopin GPIO pin for codec reset
3642 Info: Configures the Semtech SX150X I2C GPIO expanders.
3643 Load: dtoverlay=sx150x,<param>=<val>
3644 Params: sx150<x>-<n>-<m> Enables SX150X device on I2C#<n> with slave
3645 address <m>. <x> may be 1-9. <n> may be 0 or 1.
3646 Permissible values of <m> (which is denoted in
3647 hex) depend on the device variant. For SX1501,
3648 SX1502, SX1504 and SX1505, <m> may be 20 or 21.
3649 For SX1503 and SX1506, <m> may be 20. For
3650 SX1507 and SX1509, <m> may be 3E, 3F, 70 or 71.
3651 For SX1508, <m> may be 20, 21, 22 or 23.
3653 sx150<x>-<n>-<m>-int-gpio
3654 Integer, enables interrupts on SX150X device on
3655 I2C#<n> with slave address <m>, specifies
3656 the GPIO pin to which NINT output of SX150X is
3661 Info: Toshiba TC358743 HDMI to CSI-2 bridge chip.
3662 Uses Unicam 1, which is the standard camera connector on most Pi
3664 Load: dtoverlay=tc358743,<param>=<val>
3665 Params: 4lane Use 4 lanes (only applicable to Compute Modules
3668 link-frequency Set the link frequency. Only values of 297000000
3669 (574Mbit/s) and 486000000 (972Mbit/s - default)
3670 are supported by the driver.
3671 media-controller Configure use of Media Controller API for
3672 configuring the sensor (default off)
3673 cam0 Adopt the default configuration for CAM0 on a
3674 Compute Module (CSI0, i2c_vc, and cam0_reg).
3677 Name: tc358743-audio
3678 Info: Used in combination with the tc358743-fast overlay to route the audio
3679 from the TC358743 over I2S to the Pi.
3680 Wiring is LRCK/WFS to GPIO 19, BCK/SCK to GPIO 18, and DATA/SD to GPIO
3682 Load: dtoverlay=tc358743-audio,<param>=<val>
3683 Params: card-name Override the default, "tc358743", card name.
3687 Info: 3.5" Color TFT Display by www.tinylcd.com
3688 Options: Touch, RTC, keypad
3689 Load: dtoverlay=tinylcd35,<param>=<val>
3690 Params: speed Display SPI bus speed
3692 rotate Display rotation {0,90,180,270}
3694 fps Delay between frame updates
3696 debug Debug output level {0-7}
3698 touch Enable touch panel
3700 touchgpio Touch controller IRQ GPIO
3702 xohms Touchpanel: Resistance of X-plate in ohms
3704 rtc-pcf PCF8563 Real Time Clock
3706 rtc-ds DS1307 Real Time Clock
3708 keypad Enable keypad
3711 Display with touchpanel, PCF8563 RTC and keypad:
3712 dtoverlay=tinylcd35,touch,rtc-pcf,keypad
3714 dtoverlay=tinylcd35,touch,touchgpio=3
3718 Info: Enables support for Infineon SLB9670 Trusted Platform Module add-on
3719 boards, which can be used as a secure key storage and hwrng,
3720 available as "Iridium SLB9670" by Infineon and "LetsTrust TPM" by pi3g.
3721 Load: dtoverlay=tpm-slb9670
3726 Info: Change the pin usage of uart0
3727 Load: dtoverlay=uart0,<param>=<val>
3728 Params: txd0_pin GPIO pin for TXD0 (14, 32 or 36 - default 14)
3730 rxd0_pin GPIO pin for RXD0 (15, 33 or 37 - default 15)
3732 pin_func Alternative pin function - 4(Alt0) for 14&15,
3733 7(Alt3) for 32&33, 6(Alt2) for 36&37
3737 Info: Change the pin usage of uart1
3738 Load: dtoverlay=uart1,<param>=<val>
3739 Params: txd1_pin GPIO pin for TXD1 (14, 32 or 40 - default 14)
3741 rxd1_pin GPIO pin for RXD1 (15, 33 or 41 - default 15)
3745 Info: Enable uart 2 on GPIOs 0-3. BCM2711 only.
3746 Load: dtoverlay=uart2,<param>
3747 Params: ctsrts Enable CTS/RTS on GPIOs 2-3 (default off)
3751 Info: Enable uart 3 on GPIOs 4-7. BCM2711 only.
3752 Load: dtoverlay=uart3,<param>
3753 Params: ctsrts Enable CTS/RTS on GPIOs 6-7 (default off)
3757 Info: Enable uart 4 on GPIOs 8-11. BCM2711 only.
3758 Load: dtoverlay=uart4,<param>
3759 Params: ctsrts Enable CTS/RTS on GPIOs 10-11 (default off)
3763 Info: Enable uart 5 on GPIOs 12-15. BCM2711 only.
3764 Load: dtoverlay=uart5,<param>
3765 Params: ctsrts Enable CTS/RTS on GPIOs 14-15 (default off)
3769 Info: Configures the NW Digital Radio UDRC Hat
3770 Load: dtoverlay=udrc,<param>=<val>
3771 Params: alsaname Name of the ALSA audio device (default "udrc")
3774 Name: ugreen-dabboard
3775 Info: Configures the ugreen-dabboard I2S overlay
3776 This is a simple overlay based on the simple-audio-card and the dmic
3777 codec. It has the speciality that it is configured to use the codec
3778 as a master I2S device. It works for example with the Si468x DAB
3779 receiver on the uGreen DABBoard.
3780 Load: dtoverlay=ugreen-dabboard,<param>=<val>
3781 Params: card-name Override the default, "dabboard", card name.
3785 Info: Allow usage of downstream .dtb with upstream kernel. Comprises the
3786 vc4-kms-v3d and dwc2 overlays.
3787 Load: dtoverlay=upstream
3791 Name: upstream-aux-interrupt
3792 Info: This overlay has been deprecated and removed because it is no longer
3798 Info: Allow usage of downstream .dtb with upstream kernel on Pi 4. Comprises
3799 the vc4-kms-v3d-pi4 and dwc2 overlays.
3800 Load: dtoverlay=upstream-pi4
3805 Info: Enable Eric Anholt's DRM VC4 V3D driver on top of the dispmanx
3807 Load: dtoverlay=vc4-fkms-v3d,<param>
3808 Params: cma-512 CMA is 512MB (needs 1GB)
3809 cma-448 CMA is 448MB (needs 1GB)
3810 cma-384 CMA is 384MB (needs 1GB)
3811 cma-320 CMA is 320MB (needs 1GB)
3812 cma-256 CMA is 256MB (needs 1GB)
3813 cma-192 CMA is 192MB (needs 1GB)
3814 cma-128 CMA is 128MB
3817 cma-size CMA size in bytes, 4MB aligned
3818 cma-default Use upstream's default value
3821 Name: vc4-fkms-v3d-pi4
3822 Info: Enable Eric Anholt's DRM VC4 V3D driver on top of the dispmanx
3824 Load: dtoverlay=vc4-fkms-v3d-pi4,<param>
3825 Params: cma-512 CMA is 512MB (needs 1GB)
3826 cma-448 CMA is 448MB (needs 1GB)
3827 cma-384 CMA is 384MB (needs 1GB)
3828 cma-320 CMA is 320MB (needs 1GB)
3829 cma-256 CMA is 256MB (needs 1GB)
3830 cma-192 CMA is 192MB (needs 1GB)
3831 cma-128 CMA is 128MB
3834 cma-size CMA size in bytes, 4MB aligned
3835 cma-default Use upstream's default value
3838 Name: vc4-kms-dpi-at056tn53v1
3839 Info: This overlay is now deprecated - see vc4-kms-dpi-panel,at056tn53v1
3843 Name: vc4-kms-dpi-generic
3844 Info: Enable a generic DPI display under KMS. Default timings are for the
3845 Adafruit Kippah with 800x480 panel and RGB666 (GPIOs 0-21)
3846 Requires vc4-kms-v3d to be loaded.
3847 Load: dtoverlay=vc4-kms-dpi-generic,<param>=<val>
3848 Params: clock-frequency Display clock frequency (Hz)
3849 hactive Horizontal active pixels
3850 hfp Horizontal front porch
3851 hsync Horizontal sync pulse width
3852 hbp Horizontal back porch
3853 vactive Vertical active lines
3854 vfp Vertical front porch
3855 vsync Vertical sync pulse width
3856 vbp Vertical back porch
3857 hsync-invert Horizontal sync active low
3858 vsync-invert Vertical sync active low
3859 de-invert Data Enable active low
3860 pixclk-invert Negative edge pixel clock
3861 width-mm Define the screen width in mm
3862 height-mm Define the screen height in mm
3863 rgb565 Change to RGB565 output on GPIOs 0-19
3864 rgb565-padhi Change to RGB565 output on GPIOs 0-8, 12-17, and
3866 bgr666 Change to BGR666 output on GPIOs 0-21.
3867 bgr666-padhi Change to BGR666 output on GPIOs 0-9, 12-17, and
3869 rgb666-padhi Change to RGB666 output on GPIOs 0-9, 12-17, and
3871 bgr888 Change to BGR888 output on GPIOs 0-27
3872 rgb888 Change to RGB888 output on GPIOs 0-27
3873 bus-format Override the bus format for a MEDIA_BUS_FMT_*
3874 value. NB also overridden by rgbXXX overrides.
3875 backlight-gpio Defines a GPIO to be used for backlight control
3877 backlight-pwm Defines a PWM channel to be used for backlight
3878 control (default of none). NB Disables audio
3879 headphone output as that also uses PWM.
3880 backlight-pwm-chan Choose channel on &pwm node for backlight
3883 backlight-pwm-gpio GPIO pin to be used for the PWM backlight. See
3884 pwm-2chan for valid options.
3885 (default 18 - note this can only work with
3887 backlight-pwm-func Pin function of GPIO used for the PWM
3889 See pwm-2chan for valid options.
3891 backlight-def-brightness
3892 Set the default brightness. Normal range 1-16.
3894 rotate Display rotation {0,90,180,270} (default 0)
3897 Name: vc4-kms-dpi-hyperpixel2r
3898 Info: Enable the KMS drivers for the Pimoroni HyperPixel2 Round DPI display.
3899 Requires vc4-kms-v3d to be loaded.
3900 Load: dtoverlay=vc4-kms-dpi-hyperpixel2r,<param>=<val>
3901 Params: disable-touch Disables the touch controller
3902 touchscreen-inverted-x Inverts X direction of touch controller
3903 touchscreen-inverted-y Inverts Y direction of touch controller
3904 touchscreen-swapped-x-y Swaps X & Y axes of touch controller
3905 rotate Display rotation {0,90,180,270} (default 0)
3908 Name: vc4-kms-dpi-hyperpixel4
3909 Info: Enable the KMS drivers for the Pimoroni HyperPixel4 DPI display.
3910 Requires vc4-kms-v3d to be loaded.
3911 Load: dtoverlay=vc4-kms-dpi-hyperpixel4,<param>=<val>
3912 Params: disable-touch Disables the touch controller
3913 touchscreen-inverted-x Inverts X direction of touch controller
3914 touchscreen-inverted-y Inverts Y direction of touch controller
3915 touchscreen-swapped-x-y Swaps X & Y axes of touch controller
3916 rotate Display rotation {0,90,180,270} (default 0)
3919 Name: vc4-kms-dpi-hyperpixel4sq
3920 Info: Enable the KMS drivers for the Pimoroni HyperPixel4 Square DPI display.
3921 Requires vc4-kms-v3d to be loaded.
3922 Load: dtoverlay=vc4-kms-dpi-hyperpixel4sq,<param>=<val>
3923 Params: disable-touch Disables the touch controller
3924 touchscreen-inverted-x Inverts X direction of touch controller
3925 touchscreen-inverted-y Inverts Y direction of touch controller
3926 touchscreen-swapped-x-y Swaps X & Y axes of touch controller
3927 rotate Display rotation {0,90,180,270} (default 0)
3930 Name: vc4-kms-dpi-panel
3931 Info: Enable a preconfigured KMS DPI panel.
3932 Requires vc4-kms-v3d to be loaded.
3933 Load: dtoverlay=vc4-kms-dpi-panel,<param>=<val>
3934 Params: at056tn53v1 Enable an Innolux 5.6in VGA TFT
3935 kippah-7inch Enable an Adafruit Kippah with 7inch panel.
3936 mzp280 Enable a Geekworm MZP280 panel.
3937 backlight-gpio Defines a GPIO to be used for backlight control
3939 backlight-pwm Defines a PWM channel to be used for backlight
3940 control (default of none). NB Disables audio
3941 headphone output as that also uses PWM.
3942 backlight-pwm-chan Choose channel on &pwm node for backlight
3945 backlight-pwm-gpio GPIO pin to be used for the PWM backlight. See
3946 pwm-2chan for valid options.
3947 (default 18 - note this can only work with
3949 backlight-pwm-func Pin function of GPIO used for the PWM
3951 See pwm-2chan for valid options.
3953 backlight-def-brightness
3954 Set the default brightness. Normal range 1-16.
3956 rotate Display rotation {0,90,180,270} (default 0)
3959 Name: vc4-kms-dsi-7inch
3960 Info: Enable the Raspberry Pi DSI 7" screen.
3961 Includes the edt-ft5406 for the touchscreen element.
3962 Requires vc4-kms-v3d to be loaded.
3963 Load: dtoverlay=vc4-kms-dsi-7inch,<param>=<val>
3964 Params: sizex Touchscreen size x (default 800)
3965 sizey Touchscreen size y (default 480)
3966 invx Touchscreen inverted x axis
3967 invy Touchscreen inverted y axis
3968 swapxy Touchscreen swapped x y axis
3969 disable_touch Disables the touch screen overlay driver
3972 Name: vc4-kms-dsi-lt070me05000
3973 Info: Enable a JDI LT070ME05000 DSI display on DSI1.
3974 Note that this is a 4 lane DSI device, so it will only work on a Compute
3976 Requires vc4-kms-v3d to be loaded.
3977 Load: dtoverlay=vc4-kms-dsi-lt070me05000,<param>
3978 Params: reset GPIO for the reset signal (default 17)
3979 enable GPIO for the enable signal (default 4)
3980 dcdc-en GPIO for the DC-DC converter enable (default 5)
3983 Name: vc4-kms-dsi-lt070me05000-v2
3984 Info: Enable a JDI LT070ME05000 DSI display on DSI1 using Harlab's V2
3986 Note that this is a 4 lane DSI device, so it will only work on a Compute
3988 Requires vc4-kms-v3d to be loaded.
3989 Load: dtoverlay=vc4-kms-dsi-lt070me05000-v2
3993 Name: vc4-kms-kippah-7inch
3994 Info: This overlay is now deprecated - see vc4-kms-dpi-panel,kippah-7inch
3999 Info: Enable Eric Anholt's DRM VC4 HDMI/HVS/V3D driver.
4000 Load: dtoverlay=vc4-kms-v3d,<param>
4001 Params: cma-512 CMA is 512MB (needs 1GB)
4002 cma-448 CMA is 448MB (needs 1GB)
4003 cma-384 CMA is 384MB (needs 1GB)
4004 cma-320 CMA is 320MB (needs 1GB)
4005 cma-256 CMA is 256MB (needs 1GB)
4006 cma-192 CMA is 192MB (needs 1GB)
4007 cma-128 CMA is 128MB
4010 cma-size CMA size in bytes, 4MB aligned
4011 cma-default Use upstream's default value
4012 audio Enable or disable audio over HDMI (default "on")
4013 noaudio Disable all HDMI audio (default "off")
4014 composite Enable the composite output (default "off")
4015 N.B. Disables all other outputs on a Pi 4.
4018 Name: vc4-kms-v3d-pi4
4019 Info: Enable Eric Anholt's DRM VC4 HDMI/HVS/V3D driver for Pi4.
4020 Load: dtoverlay=vc4-kms-v3d-pi4,<param>
4021 Params: cma-512 CMA is 512MB
4022 cma-448 CMA is 448MB
4023 cma-384 CMA is 384MB
4024 cma-320 CMA is 320MB
4025 cma-256 CMA is 256MB
4026 cma-192 CMA is 192MB
4027 cma-128 CMA is 128MB
4030 cma-size CMA size in bytes, 4MB aligned
4031 cma-default Use upstream's default value
4032 audio Enable or disable audio over HDMI0 (default
4034 audio1 Enable or disable audio over HDMI1 (default
4036 noaudio Disable all HDMI audio (default "off")
4037 composite Enable the composite output (disables all other
4041 Name: vc4-kms-vga666
4042 Info: Enable the VGA666 (resistor ladder ADC) for the vc4-kms-v3d driver.
4043 Requires vc4-kms-v3d to be loaded.
4044 Load: dtoverlay=vc4-kms-vga666,<param>
4045 Params: ddc Enables GPIOs 0&1 as the I2C to read the EDID
4046 from the display. NB These are NOT 5V tolerant
4047 GPIOs, therefore level shifters are required.
4051 Info: Overlay for the Fen Logic VGA666 board
4052 This uses GPIOs 2-21 (so no I2C), and activates the output 2-3 seconds
4053 after the kernel has started.
4054 NOT for use with vc4-kms-v3d.
4055 Load: dtoverlay=vga666
4060 Info: Overlay to enable a VIA VL805 USB3 controller on CM4 carriers
4061 Will be loaded automatically by up-to-date firmware if "VL805=1" is
4062 set in the EEPROM config.
4063 Load: dtoverlay=vl805
4068 Info: Configures the w1-gpio Onewire interface module.
4069 Use this overlay if you *don't* need a GPIO to drive an external pullup.
4070 Load: dtoverlay=w1-gpio,<param>=<val>
4071 Params: gpiopin GPIO for I/O (default "4")
4072 pullup Now enabled by default (ignored)
4075 Name: w1-gpio-pullup
4076 Info: Configures the w1-gpio Onewire interface module.
4077 Use this overlay if you *do* need a GPIO to drive an external pullup.
4078 Load: dtoverlay=w1-gpio-pullup,<param>=<val>
4079 Params: gpiopin GPIO for I/O (default "4")
4080 extpullup GPIO for external pullup (default "5")
4081 pullup Now enabled by default (ignored)
4085 Info: Overlay for the Wiznet W5500 Ethernet Controller on SPI0
4086 Load: dtoverlay=w5500,<param>=<val>
4087 Params: int_pin GPIO used for INT (default 25)
4089 speed SPI bus speed (default 30000000)
4091 cs SPI bus Chip Select (default 0)
4094 Name: waveshare-can-fd-hat-mode-a
4095 Info: Overlay for the Waveshare 2-Channel Isolated CAN FD Expansion HAT
4096 for Raspberry Pi, Multi Protections. Use this overlay when the
4097 HAT is configured in Mode A (Default), with can0 on spi0.0
4099 https://www.waveshare.com/2-ch-can-fd-hat.htm
4100 Load: dtoverlay=waveshare-can-fd-hat-mode-a
4104 Name: waveshare-can-fd-hat-mode-b
4105 Info: Overlay for the Waveshare 2-Channel Isolated CAN FD Expansion HAT
4106 for Raspberry Pi, Multi Protections. Use this overlay when the
4107 HAT is configured in Mode B (requires hardware modification), with
4108 can0 on spi0.0 and can1 on spi0.1.
4109 https://www.waveshare.com/2-ch-can-fd-hat.htm
4110 Load: dtoverlay=waveshare-can-fd-hat-mode-b
4115 Info: Configures the wittypi RTC module.
4116 Load: dtoverlay=wittypi,<param>=<val>
4117 Params: led_gpio GPIO for LED (default "17")
4118 led_trigger Choose which activity the LED tracks (default
4122 Name: wm8960-soundcard
4123 Info: Overlay for the Waveshare wm8960 soundcard
4124 Load: dtoverlay=wm8960-soundcard,<param>=<val>
4125 Params: alsaname Changes the card name in ALSA
4126 compatible Changes the codec compatibility
4132 If you are experiencing problems that you think are DT-related, enable DT
4133 diagnostic output by adding this to /boot/config.txt:
4137 and rebooting. Then run:
4141 and look for relevant messages.
4146 This is only meant to be a quick introduction to the subject of Device Tree on
4147 Raspberry Pi. There is a more complete explanation here:
4149 http://www.raspberrypi.org/documentation/configuration/device-tree.md