1 # SPDX-License-Identifier: GPL-2.0
3 # Character device configuration
6 menu "Character devices"
8 source "drivers/char/broadcom/Kconfig"
10 source "drivers/tty/Kconfig"
13 tristate "TTY driver to output user messages via printk"
14 depends on EXPERT && TTY
17 If you say Y here, the support for writing user messages (i.e.
18 console messages) via printk is available.
20 The feature is useful to inline user messages with kernel
22 In order to use this feature, you should output user messages
23 to /dev/ttyprintk or redirect console to this TTY.
27 config TTY_PRINTK_LEVEL
29 int "ttyprintk log level (1-7)"
33 Printk log level to use for ttyprintk messages.
36 tristate "Parallel printer support"
39 If you intend to attach a printer to the parallel port of your Linux
40 box (as opposed to using a serial printer; if the connector at the
41 printer has 9 or 25 holes ["female"], then it's serial), say Y.
42 Also read the Printing-HOWTO, available from
43 <https://www.tldp.org/docs.html#howto>.
45 It is possible to share one parallel port among several devices
46 (e.g. printer and ZIP drive) and it is safe to compile the
47 corresponding drivers into the kernel.
49 To compile this driver as a module, choose M here and read
50 <file:Documentation/admin-guide/parport.rst>. The module will be called lp.
52 If you have several parallel ports, you can specify which ports to
53 use with the "lp" kernel command line option. (Try "man bootparam"
54 or see the documentation of your boot loader (lilo or loadlin) about
55 how to pass options to the kernel at boot time.) The syntax of the
56 "lp" command line option can be found in <file:drivers/char/lp.c>.
58 If you have more than 8 printers, you need to increase the LP_NO
59 macro in lp.c and the PARPORT_MAX macro in parport.h.
62 bool "Support for console on line printer"
65 If you want kernel messages to be printed out as they occur, you
66 can have a console on the printer. This option adds support for
67 doing that; to actually get it to happen you need to pass the
68 option "console=lp0" to the kernel at boot time.
70 If the printer is out of paper (or off, or unplugged, or too
71 busy..) the kernel will stall until the printer is ready again.
72 By defining CONSOLE_LP_STRICT to 0 (at your own risk) you
73 can make the kernel continue when this happens,
74 but it'll lose the kernel messages.
79 tristate "Support for user-space parallel port device drivers"
82 Saying Y to this adds support for /dev/parport device nodes. This
83 is needed for programs that want portable access to the parallel
84 port, for instance deviceid (which displays Plug-and-Play device
87 This is the parallel port equivalent of SCSI generic support (sg).
88 It is safe to say N to this -- it is not needed for normal printing
89 or parallel port CD-ROM/disk support.
91 To compile this driver as a module, choose M here: the
92 module will be called ppdev.
97 tristate "Virtio console"
102 Virtio console for use with hypervisors.
104 Also serves as a general-purpose serial device for data
105 transfer between the guest and host. Character devices at
106 /dev/vportNpn will be created when corresponding ports are
107 found, where N is the device number and n is the port number
108 within that device. If specified by the host, a sysfs
109 attribute called 'name' will be populated with a name for
110 the port which can be used by udev scripts to create a
111 symlink to the device.
114 tristate "IBM POWER Barrier Synchronization Register support"
115 depends on PPC_PSERIES
117 This devices exposes a hardware mechanism for fast synchronization
118 of threads across a large system which avoids bouncing a cacheline
119 between several cores on a system
121 config POWERNV_OP_PANEL
122 tristate "IBM POWERNV Operator Panel Display support"
123 depends on PPC_POWERNV
126 If you say Y here, a special character device node, /dev/op_panel,
127 will be created which exposes the operator panel display on IBM
128 Power Systems machines with FSPs.
130 If you don't require access to the operator panel display from user
133 If unsure, say M here to build it as a module called powernv-op-panel.
135 source "drivers/char/ipmi/Kconfig"
138 tristate "NetWinder thermometer support"
139 depends on ARCH_NETWINDER
141 Say Y here to include support for the thermal management hardware
142 found in the NetWinder. This driver allows the user to control the
143 temperature set points and to read the current temperature.
145 It is also possible to say M here to build it as a module (ds1620)
146 It is recommended to be used on a NetWinder, but it is not a
150 tristate "NetWinder Button"
151 depends on ARCH_NETWINDER
153 If you say Y here and create a character device node /dev/nwbutton
154 with major and minor numbers 10 and 158 ("man mknod"), then every
155 time the orange button is pressed a number of times, the number of
156 times the button was pressed will be written to that device.
158 This is most useful for applications, as yet unwritten, which
159 perform actions based on how many times the button is pressed in a
162 Do not hold the button down for too long, as the driver does not
163 alter the behaviour of the hardware reset circuitry attached to the
164 button; it will still execute a hard reset if the button is held
165 down for longer than approximately five seconds.
167 To compile this driver as a module, choose M here: the
168 module will be called nwbutton.
170 Most people will answer Y to this question and "Reboot Using Button"
171 below to be able to initiate a system shutdown from the button.
173 config NWBUTTON_REBOOT
174 bool "Reboot Using Button"
177 If you say Y here, then you will be able to initiate a system
178 shutdown and reboot by pressing the orange button a number of times.
179 The number of presses to initiate the shutdown is two by default,
180 but this can be altered by modifying the value of NUM_PRESSES_REBOOT
181 in nwbutton.h and recompiling the driver or, if you compile the
182 driver as a module, you can specify the number of presses at load
183 time with "insmod button reboot_count=<something>".
186 tristate "NetWinder flash support"
187 depends on ARCH_NETWINDER
189 If you say Y here and create a character device /dev/flash with
190 major 10 and minor 160 you can manipulate the flash ROM containing
191 the NetWinder firmware. Be careful as accidentally overwriting the
192 flash contents can render your computer unbootable. On no account
193 allow random users access to this device. :-)
195 To compile this driver as a module, choose M here: the
196 module will be called nwflash.
198 If you're not sure, say N.
200 source "drivers/char/hw_random/Kconfig"
203 tristate "Double Talk PC internal speech card support"
206 This driver is for the DoubleTalk PC, a speech synthesizer
207 manufactured by RC Systems (<https://www.rcsys.com/>). It is also
208 called the `internal DoubleTalk'.
210 To compile this driver as a module, choose M here: the
211 module will be called dtlk.
214 tristate "Xilinx HWICAP Support"
215 depends on MICROBLAZE
217 This option enables support for Xilinx Internal Configuration
218 Access Port (ICAP) driver. The ICAP is used on Xilinx Virtex
219 FPGA platforms to partially reconfigure the FPGA at runtime.
224 tristate "Applicom intelligent fieldbus card support"
227 This driver provides the kernel-side support for the intelligent
228 fieldbus cards made by Applicom International. More information
229 about these cards can be found on the WWW at the address
230 <https://www.applicom-int.com/>, or by email from David Woodhouse
231 <dwmw2@infradead.org>.
233 To compile this driver as a module, choose M here: the
234 module will be called applicom.
239 tristate "Sony Vaio Programmable I/O Control Device support"
240 depends on X86_32 && PCI && INPUT
242 This driver enables access to the Sony Programmable I/O Control
243 Device which can be found in many (all ?) Sony Vaio laptops.
245 If you have one of those laptops, read
246 <file:Documentation/admin-guide/laptops/sonypi.rst>, and say Y or M here.
248 To compile this driver as a module, choose M here: the
249 module will be called sonypi.
252 tristate "TANBAC TB0219 GPIO support"
253 depends on TANBAC_TB022X
256 source "drivers/char/pcmcia/Kconfig"
259 tristate "ACP Modem (Mwave) support"
260 depends on X86 && TTY
263 The ACP modem (Mwave) for Linux is a WinModem. It is composed of a
264 kernel driver and a user level application. Together these components
265 support direct attachment to public switched telephone networks (PSTNs)
266 and support selected world wide countries.
268 This version of the ACP Modem driver supports the IBM Thinkpad 600E,
269 600, and 770 that include on board ACP modem hardware.
271 The modem also supports the standard communications port interface
272 (ttySx) and is compatible with the Hayes AT Command Set.
274 The user level application needed to use this driver can be found at
275 the IBM Linux Technology Center (LTC) web site:
276 <http://www.ibm.com/linux/ltc/>.
278 If you own one of the above IBM Thinkpads which has the Mwave chipset
281 To compile this driver as a module, choose M here: the
282 module will be called mwave.
285 tristate "NatSemi SCx200 GPIO Support"
289 Give userspace access to the GPIO pins on the National
290 Semiconductor SCx200 processors.
292 If compiled as a module, it will be called scx200_gpio.
295 tristate "NatSemi PC8736x GPIO Support"
296 depends on X86_32 && !UML
297 default SCx200_GPIO # mostly N
298 select NSC_GPIO # needed for support routines
300 Give userspace access to the GPIO pins on the National
301 Semiconductor PC-8736x (x=[03456]) SuperIO chip. The chip
302 has multiple functional units, inc several managed by
303 hwmon/pc87360 driver. Tested with PC-87366
305 If compiled as a module, it will be called pc8736x_gpio.
308 tristate "NatSemi Base GPIO Support"
310 # selected by SCx200_GPIO and PC8736x_GPIO
311 # what about 2 selectors differing: m != y
313 Common support used (and needed) by scx200_gpio and
314 pc8736x_gpio drivers. If those drivers are built as
315 modules, this one will be too, named nsc_gpio
318 bool "/dev/mem virtual device support"
321 Say Y here if you want to support the /dev/mem device.
322 The /dev/mem device is used to access areas of physical
324 When in doubt, say "Y".
327 tristate "/dev/nvram support"
328 depends on X86 || HAVE_ARCH_NVRAM_OPS
331 If you say Y here and create a character special file /dev/nvram
332 with major number 10 and minor number 144 using mknod ("man mknod"),
333 you get read and write access to the non-volatile memory.
335 /dev/nvram may be used to view settings in NVRAM or to change them
336 (with some utility). It could also be used to frequently
337 save a few bits of very important data that may not be lost over
338 power-off and for which writing to disk is too insecure. Note
339 however that most NVRAM space in a PC belongs to the BIOS and you
340 should NEVER idly tamper with it. See Ralf Brown's interrupt list
341 for a guide to the use of CMOS bytes by your BIOS.
343 This memory is conventionally called "NVRAM" on PowerPC machines,
344 "CMOS RAM" on PCs, "NVRAM" on Ataris and "PRAM" on Macintoshes.
346 To compile this driver as a module, choose M here: the
347 module will be called nvram.
350 bool "/dev/port character device"
351 depends on ISA || PCI
354 Say Y here if you want to support the /dev/port device. The /dev/port
355 device is similar to /dev/mem, but for I/O ports.
358 bool "HPET - High Precision Event Timer" if (X86 || IA64)
362 If you say Y here, you will have a miscdevice named "/dev/hpet/". Each
363 open selects one of the timers supported by the HPET. The timers are
364 non-periodic and/or periodic.
367 bool "Allow mmap of HPET"
371 If you say Y here, user applications will be able to mmap
374 config HPET_MMAP_DEFAULT
375 bool "Enable HPET MMAP access by default"
379 In some hardware implementations, the page containing HPET
380 registers may also contain other things that shouldn't be
381 exposed to the user. This option selects the default (if
382 kernel parameter hpet_mmap is not set) user access to the
383 registers for applications that require it.
385 config HANGCHECK_TIMER
386 tristate "Hangcheck timer"
387 depends on X86 || IA64 || PPC64 || S390
389 The hangcheck-timer module detects when the system has gone
390 out to lunch past a certain margin. It can reboot the system
391 or merely print a warning.
394 tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
398 The uv_mmtimer device allows direct userspace access to the
401 source "drivers/char/tpm/Kconfig"
404 tristate "Telecom clock driver for ATCA SBC"
408 The telecom clock device is specific to the MPCBL0010 and MPCBL0050
409 ATCA computers and allows direct userspace access to the
410 configuration of the telecom clock configuration settings. This
411 device is used for hardware synchronization across the ATCA backplane
412 fabric. Upon loading, the driver exports a sysfs directory,
413 /sys/devices/platform/telco_clock, with a number of files for
414 controlling the behavior of this hardware.
416 source "drivers/s390/char/Kconfig"
418 source "drivers/char/xillybus/Kconfig"
421 tristate "SPARC Privileged ADI driver"
425 SPARC M7 and newer processors utilize ADI (Application Data
426 Integrity) to version and protect memory. This driver provides
427 read/write access to the ADI versions for privileged processes.
428 This feature is also known as MCD (Memory Corruption Detection)
429 and SSM (Silicon Secured Memory). Intended consumers of this
430 driver include crash and makedumpfile.
432 config RANDOM_TRUST_CPU
433 bool "Initialize RNG using CPU RNG instructions"
435 depends on ARCH_RANDOM
437 Initialize the RNG using random numbers supplied by the CPU's
438 RNG instructions (e.g. RDRAND), if supported and available. These
439 random numbers are never used directly, but are rather hashed into
440 the main input pool, and this happens regardless of whether or not
441 this option is enabled. Instead, this option controls whether the
442 they are credited and hence can initialize the RNG. Additionally,
443 other sources of randomness are always used, regardless of this
444 setting. Enabling this implies trusting that the CPU can supply high
445 quality and non-backdoored random numbers.
447 Say Y here unless you have reason to mistrust your CPU or believe
448 its RNG facilities may be faulty. This may also be configured at
449 boot time with "random.trust_cpu=on/off".
451 config RANDOM_TRUST_BOOTLOADER
452 bool "Initialize RNG using bootloader-supplied seed"
455 Initialize the RNG using a seed supplied by the bootloader or boot
456 environment (e.g. EFI or a bootloader-generated device tree). This
457 seed is not used directly, but is rather hashed into the main input
458 pool, and this happens regardless of whether or not this option is
459 enabled. Instead, this option controls whether the seed is credited
460 and hence can initialize the RNG. Additionally, other sources of
461 randomness are always used, regardless of this setting. Enabling
462 this implies trusting that the bootloader can supply high quality and
463 non-backdoored seeds.
465 Say Y here unless you have reason to mistrust your bootloader or
466 believe its RNG facilities may be faulty. This may also be configured
467 at boot time with "random.trust_bootloader=on/off".