1 # SPDX-License-Identifier: GPL-2.0
3 # USB Gadget support on a system involves
4 # (a) a peripheral controller, and
5 # (b) the gadget driver using it.
7 # NOTE: Gadget support ** DOES NOT ** depend on host-side CONFIG_USB !!
9 # - Host systems (like PCs) need CONFIG_USB (with "A" jacks).
10 # - Peripherals (like PDAs) need CONFIG_USB_GADGET (with "B" jacks).
11 # - Some systems have both kinds of controllers.
13 # With help from a special transceiver and a "Mini-AB" jack, systems with
14 # both kinds of controller can also support "USB On-the-Go" (CONFIG_USB_OTG).
18 tristate "USB Gadget Support"
22 USB is a host/device protocol, organized with one host (such as a
23 PC) controlling up to 127 peripheral devices.
24 The USB hardware is asymmetric, which makes it easier to set up:
25 you can't connect a "to-the-host" connector to a peripheral.
27 Linux can run in the host, or in the peripheral. In both cases
28 you need a low level bus controller driver, and some software
29 talking to it. Peripheral controllers are often discrete silicon,
30 or are integrated with the CPU in a microcontroller. The more
31 familiar host side controllers have names like "EHCI", "OHCI",
32 or "UHCI", and are usually integrated into southbridges on PC
35 Enable this configuration option if you want to run Linux inside
36 a USB peripheral device. Configure one hardware driver for your
37 peripheral/device side bus controller, and a "gadget driver" for
38 your peripheral protocol. (If you use modular gadget drivers,
39 you may configure more than one.)
41 If in doubt, say "N" and don't enable these drivers; most people
42 don't have this kind of hardware (except maybe inside Linux PDAs).
44 For more information, see <http://www.linux-usb.org/gadget> and
45 the kernel documentation for this API.
49 config USB_GADGET_DEBUG
50 bool "Debugging messages (DEVELOPMENT)"
51 depends on DEBUG_KERNEL
53 Many controller and gadget drivers will print some debugging
54 messages if you use this option to ask for those messages.
56 Avoid enabling these messages, even if you're actively
57 debugging such a driver. Many drivers will emit so many
58 messages that the driver timings are affected, which will
59 either create new failure modes or remove the one you're
60 trying to track down. Never enable these messages for a
63 config USB_GADGET_VERBOSE
64 bool "Verbose debugging Messages (DEVELOPMENT)"
65 depends on USB_GADGET_DEBUG
67 Many controller and gadget drivers will print verbose debugging
68 messages if you use this option to ask for those messages.
70 Avoid enabling these messages, even if you're actively
71 debugging such a driver. Many drivers will emit so many
72 messages that the driver timings are affected, which will
73 either create new failure modes or remove the one you're
74 trying to track down. Never enable these messages for a
77 config USB_GADGET_DEBUG_FILES
78 bool "Debugging information files (DEVELOPMENT)"
81 Some of the drivers in the "gadget" framework can expose
82 debugging information in files such as /proc/driver/udc
83 (for a peripheral controller). The information in these
84 files may help when you're troubleshooting or bringing up a
85 driver on a new board. Enable these files by choosing "Y"
86 here. If in doubt, or to conserve kernel memory, say "N".
88 config USB_GADGET_DEBUG_FS
89 bool "Debugging information files in debugfs (DEVELOPMENT)"
92 Some of the drivers in the "gadget" framework can expose
93 debugging information in files under /sys/kernel/debug/.
94 The information in these files may help when you're
95 troubleshooting or bringing up a driver on a new board.
96 Enable these files by choosing "Y" here. If in doubt, or
97 to conserve kernel memory, say "N".
99 config USB_GADGET_VBUS_DRAW
100 int "Maximum VBUS Power usage (2-500 mA)"
104 Some devices need to draw power from USB when they are
105 configured, perhaps to operate circuitry or to recharge
106 batteries. This is in addition to any local power supply,
107 such as an AC adapter or batteries.
109 Enter the maximum power your device draws through USB, in
110 milliAmperes. The permitted range of values is 2 - 500 mA;
111 0 mA would be legal, but can make some hosts misbehave.
113 This value will be used except for system-specific gadget
114 drivers that have more specific information.
116 config USB_GADGET_STORAGE_NUM_BUFFERS
117 int "Number of storage pipeline buffers"
121 Usually 2 buffers are enough to establish a good buffering
122 pipeline. The number may be increased in order to compensate
123 for a bursty VFS behaviour. For instance there may be CPU wake up
124 latencies that makes the VFS to appear bursty in a system with
125 an CPU on-demand governor. Especially if DMA is doing IO to
126 offload the CPU. In this case the CPU will go into power
127 save often and spin up occasionally to move data within VFS.
128 If selecting USB_GADGET_DEBUG_FILES this value may be set by
129 a module parameter as well.
132 config U_SERIAL_CONSOLE
133 bool "Serial gadget console support"
134 depends on USB_U_SERIAL
136 It supports the serial gadget can be used as a console.
138 source "drivers/usb/gadget/udc/Kconfig"
144 # composite based drivers
145 config USB_LIBCOMPOSITE
148 depends on USB_GADGET
189 config USB_F_MASS_STORAGE
198 config USB_F_UAC1_LEGACY
223 # this first set of drivers all depend on bulk-capable hardware.
226 tristate "USB Gadget functions configurable through configfs"
227 select USB_LIBCOMPOSITE
229 A Linux USB "gadget" can be set up through configfs.
230 If this is the case, the USB functions (which from the host's
231 perspective are seen as interfaces) and configurations are
232 specified simply by creating appropriate directories in configfs.
233 Associating functions with configurations is done by creating
234 appropriate symbolic links.
235 For more information see Documentation/usb/gadget_configfs.rst.
237 config USB_CONFIGFS_SERIAL
238 bool "Generic serial bulk in/out"
239 depends on USB_CONFIGFS
244 The function talks to the Linux-USB generic serial driver.
246 config USB_CONFIGFS_ACM
247 bool "Abstract Control Model (CDC ACM)"
248 depends on USB_CONFIGFS
253 ACM serial link. This function can be used to interoperate with
254 MS-Windows hosts or with the Linux-USB "cdc-acm" driver.
256 config USB_CONFIGFS_OBEX
257 bool "Object Exchange Model (CDC OBEX)"
258 depends on USB_CONFIGFS
263 You will need a user space OBEX server talking to /dev/ttyGS*,
264 since the kernel itself doesn't implement the OBEX protocol.
266 config USB_CONFIGFS_NCM
267 bool "Network Control Model (CDC NCM)"
268 depends on USB_CONFIGFS
274 NCM is an advanced protocol for Ethernet encapsulation, allows
275 grouping of several ethernet frames into one USB transfer and
276 different alignment possibilities.
278 config USB_CONFIGFS_ECM
279 bool "Ethernet Control Model (CDC ECM)"
280 depends on USB_CONFIGFS
285 The "Communication Device Class" (CDC) Ethernet Control Model.
286 That protocol is often avoided with pure Ethernet adapters, in
287 favor of simpler vendor-specific hardware, but is widely
288 supported by firmware for smart network devices.
290 config USB_CONFIGFS_ECM_SUBSET
291 bool "Ethernet Control Model (CDC ECM) subset"
292 depends on USB_CONFIGFS
297 On hardware that can't implement the full protocol,
298 a simple CDC subset is used, placing fewer demands on USB.
300 config USB_CONFIGFS_RNDIS
302 depends on USB_CONFIGFS
307 Microsoft Windows XP bundles the "Remote NDIS" (RNDIS) protocol,
308 and Microsoft provides redistributable binary RNDIS drivers for
309 older versions of Windows.
311 To make MS-Windows work with this, use Documentation/usb/linux.inf
312 as the "driver info file". For versions of MS-Windows older than
313 XP, you'll need to download drivers from Microsoft's website; a URL
314 is given in comments found in that info file.
316 config USB_CONFIGFS_EEM
317 bool "Ethernet Emulation Model (EEM)"
318 depends on USB_CONFIGFS
324 CDC EEM is a newer USB standard that is somewhat simpler than CDC ECM
325 and therefore can be supported by more hardware. Technically ECM and
326 EEM are designed for different applications. The ECM model extends
327 the network interface to the target (e.g. a USB cable modem), and the
328 EEM model is for mobile devices to communicate with hosts using
329 ethernet over USB. For Linux gadgets, however, the interface with
330 the host is the same (a usbX device), so the differences are minimal.
332 config USB_CONFIGFS_PHONET
333 bool "Phonet protocol"
334 depends on USB_CONFIGFS
340 The Phonet protocol implementation for USB device.
342 config USB_CONFIGFS_MASS_STORAGE
344 depends on USB_CONFIGFS
346 select USB_F_MASS_STORAGE
348 The Mass Storage Gadget acts as a USB Mass Storage disk drive.
349 As its storage repository it can use a regular file or a block
350 device (in much the same way as the "loop" device driver),
351 specified as a module parameter or sysfs option.
353 config USB_CONFIGFS_F_LB_SS
354 bool "Loopback and sourcesink function (for testing)"
355 depends on USB_CONFIGFS
358 Loopback function loops back a configurable number of transfers.
359 Sourcesink function either sinks and sources bulk data.
360 It also implements control requests, for "chapter 9" conformance.
361 Make this be the first driver you try using on top of any new
362 USB peripheral controller driver. Then you can use host-side
363 test software, like the "usbtest" driver, to put your hardware
364 and its driver through a basic set of functional tests.
366 config USB_CONFIGFS_F_FS
367 bool "Function filesystem (FunctionFS)"
368 depends on USB_CONFIGFS
371 The Function Filesystem (FunctionFS) lets one create USB
372 composite functions in user space in the same way GadgetFS
373 lets one create USB gadgets in user space. This allows creation
374 of composite gadgets such that some of the functions are
375 implemented in kernel space (for instance Ethernet, serial or
376 mass storage) and other are implemented in user space.
378 config USB_CONFIGFS_F_UAC1
379 bool "Audio Class 1.0"
380 depends on USB_CONFIGFS
382 select USB_LIBCOMPOSITE
387 This Audio function implements 1 AudioControl interface,
388 1 AudioStreaming Interface each for USB-OUT and USB-IN.
389 This driver doesn't expect any real Audio codec to be present
390 on the device - the audio streams are simply sinked to and
391 sourced from a virtual ALSA sound card created. The user-space
392 application may choose to do whatever it wants with the data
393 received from the USB Host and choose to provide whatever it
394 wants as audio data to the USB Host.
396 config USB_CONFIGFS_F_UAC1_LEGACY
397 bool "Audio Class 1.0 (legacy implementation)"
398 depends on USB_CONFIGFS
400 select USB_LIBCOMPOSITE
402 select USB_F_UAC1_LEGACY
404 This Audio function implements 1 AudioControl interface,
405 1 AudioStreaming Interface each for USB-OUT and USB-IN.
406 This is a legacy driver and requires a real Audio codec
407 to be present on the device.
409 config USB_CONFIGFS_F_UAC2
410 bool "Audio Class 2.0"
411 depends on USB_CONFIGFS
413 select USB_LIBCOMPOSITE
418 This Audio function is compatible with USB Audio Class
419 specification 2.0. It implements 1 AudioControl interface,
420 1 AudioStreaming Interface each for USB-OUT and USB-IN.
421 This driver doesn't expect any real Audio codec to be present
422 on the device - the audio streams are simply sinked to and
423 sourced from a virtual ALSA sound card created. The user-space
424 application may choose to do whatever it wants with the data
425 received from the USB Host and choose to provide whatever it
426 wants as audio data to the USB Host.
428 config USB_CONFIGFS_F_MIDI
430 depends on USB_CONFIGFS
432 select USB_LIBCOMPOSITE
436 The MIDI Function acts as a USB Audio device, with one MIDI
437 input and one MIDI output. These MIDI jacks appear as
438 a sound "card" in the ALSA sound system. Other MIDI
439 connections can then be made on the gadget system, using
440 ALSA's aconnect utility etc.
442 config USB_CONFIGFS_F_MIDI2
443 bool "MIDI 2.0 function"
444 depends on USB_CONFIGFS
446 select USB_LIBCOMPOSITE
448 select SND_UMP_LEGACY_RAWMIDI
451 The MIDI 2.0 function driver provides the generic emulated
452 USB MIDI 2.0 interface, looped back to ALSA UMP rawmidi
453 device on the gadget host. It supports UMP 1.1 spec and
454 responds UMP Stream messages for UMP Endpoint and Function
455 Block information / configuration.
457 config USB_CONFIGFS_F_HID
459 depends on USB_CONFIGFS
462 The HID function driver provides generic emulation of USB
463 Human Interface Devices (HID).
465 For more information, see Documentation/usb/gadget_hid.rst.
467 config USB_CONFIGFS_F_UVC
468 bool "USB Webcam function"
469 depends on USB_CONFIGFS
472 select VIDEOBUF2_DMA_SG
473 select VIDEOBUF2_VMALLOC
476 The Webcam function acts as a composite USB Audio and Video Class
477 device. It provides a userspace API to process UVC control requests
478 and stream video data to the host.
480 config USB_CONFIGFS_F_PRINTER
481 bool "Printer function"
483 depends on USB_CONFIGFS
485 The Printer function channels data between the USB host and a
486 userspace program driving the print engine. The user space
487 program reads and writes the device file /dev/g_printer<X> to
488 receive or send printer data. It can use ioctl calls to
489 the device file to get or set printer status.
491 For more information, see Documentation/usb/gadget_printer.rst
492 which includes sample code for accessing the device file.
494 config USB_CONFIGFS_F_TCM
495 bool "USB Gadget Target Fabric"
496 depends on TARGET_CORE
497 depends on USB_CONFIGFS
498 select USB_LIBCOMPOSITE
501 This fabric is a USB gadget component. Two USB protocols are
502 supported that is BBB or BOT (Bulk Only Transport) and UAS
503 (USB Attached SCSI). BOT is advertised on alternative
504 interface 0 (primary) and UAS is on alternative interface 1.
505 Both protocols can work on USB2.0 and USB3.0.
506 UAS utilizes the USB 3.0 feature called streams support.
508 source "drivers/usb/gadget/legacy/Kconfig"