0001 # SPDX-License-Identifier: GPL-2.0
0002 #
0003 # Character device configuration
0004 #
0005
0006 menu "Character devices"
0007
0008 source "drivers/tty/Kconfig"
0009
0010 config TTY_PRINTK
0011 tristate "TTY driver to output user messages via printk"
0012 depends on EXPERT && TTY
0013 default n
0014 help
0015 If you say Y here, the support for writing user messages (i.e.
0016 console messages) via printk is available.
0017
0018 The feature is useful to inline user messages with kernel
0019 messages.
0020 In order to use this feature, you should output user messages
0021 to /dev/ttyprintk or redirect console to this TTY, or boot
0022 the kernel with console=ttyprintk.
0023
0024 If unsure, say N.
0025
0026 config TTY_PRINTK_LEVEL
0027 depends on TTY_PRINTK
0028 int "ttyprintk log level (1-7)"
0029 range 1 7
0030 default "6"
0031 help
0032 Printk log level to use for ttyprintk messages.
0033
0034 config PRINTER
0035 tristate "Parallel printer support"
0036 depends on PARPORT
0037 help
0038 If you intend to attach a printer to the parallel port of your Linux
0039 box (as opposed to using a serial printer; if the connector at the
0040 printer has 9 or 25 holes ["female"], then it's serial), say Y.
0041 Also read the Printing-HOWTO, available from
0042 <https://www.tldp.org/docs.html#howto>.
0043
0044 It is possible to share one parallel port among several devices
0045 (e.g. printer and ZIP drive) and it is safe to compile the
0046 corresponding drivers into the kernel.
0047
0048 To compile this driver as a module, choose M here and read
0049 <file:Documentation/admin-guide/parport.rst>. The module will be called lp.
0050
0051 If you have several parallel ports, you can specify which ports to
0052 use with the "lp" kernel command line option. (Try "man bootparam"
0053 or see the documentation of your boot loader (lilo or loadlin) about
0054 how to pass options to the kernel at boot time.) The syntax of the
0055 "lp" command line option can be found in <file:drivers/char/lp.c>.
0056
0057 If you have more than 8 printers, you need to increase the LP_NO
0058 macro in lp.c and the PARPORT_MAX macro in parport.h.
0059
0060 config LP_CONSOLE
0061 bool "Support for console on line printer"
0062 depends on PRINTER
0063 help
0064 If you want kernel messages to be printed out as they occur, you
0065 can have a console on the printer. This option adds support for
0066 doing that; to actually get it to happen you need to pass the
0067 option "console=lp0" to the kernel at boot time.
0068
0069 If the printer is out of paper (or off, or unplugged, or too
0070 busy..) the kernel will stall until the printer is ready again.
0071 By defining CONSOLE_LP_STRICT to 0 (at your own risk) you
0072 can make the kernel continue when this happens,
0073 but it'll lose the kernel messages.
0074
0075 If unsure, say N.
0076
0077 config PPDEV
0078 tristate "Support for user-space parallel port device drivers"
0079 depends on PARPORT
0080 help
0081 Saying Y to this adds support for /dev/parport device nodes. This
0082 is needed for programs that want portable access to the parallel
0083 port, for instance deviceid (which displays Plug-and-Play device
0084 IDs).
0085
0086 This is the parallel port equivalent of SCSI generic support (sg).
0087 It is safe to say N to this -- it is not needed for normal printing
0088 or parallel port CD-ROM/disk support.
0089
0090 To compile this driver as a module, choose M here: the
0091 module will be called ppdev.
0092
0093 If unsure, say N.
0094
0095 config VIRTIO_CONSOLE
0096 tristate "Virtio console"
0097 depends on TTY
0098 select HVC_DRIVER
0099 select VIRTIO
0100 help
0101 Virtio console for use with hypervisors.
0102
0103 Also serves as a general-purpose serial device for data
0104 transfer between the guest and host. Character devices at
0105 /dev/vportNpn will be created when corresponding ports are
0106 found, where N is the device number and n is the port number
0107 within that device. If specified by the host, a sysfs
0108 attribute called 'name' will be populated with a name for
0109 the port which can be used by udev scripts to create a
0110 symlink to the device.
0111
0112 config IBM_BSR
0113 tristate "IBM POWER Barrier Synchronization Register support"
0114 depends on PPC_PSERIES
0115 help
0116 This devices exposes a hardware mechanism for fast synchronization
0117 of threads across a large system which avoids bouncing a cacheline
0118 between several cores on a system
0119
0120 config POWERNV_OP_PANEL
0121 tristate "IBM POWERNV Operator Panel Display support"
0122 depends on PPC_POWERNV
0123 default m
0124 help
0125 If you say Y here, a special character device node, /dev/op_panel,
0126 will be created which exposes the operator panel display on IBM
0127 Power Systems machines with FSPs.
0128
0129 If you don't require access to the operator panel display from user
0130 space, say N.
0131
0132 If unsure, say M here to build it as a module called powernv-op-panel.
0133
0134 source "drivers/char/ipmi/Kconfig"
0135
0136 config DS1620
0137 tristate "NetWinder thermometer support"
0138 depends on ARCH_NETWINDER
0139 help
0140 Say Y here to include support for the thermal management hardware
0141 found in the NetWinder. This driver allows the user to control the
0142 temperature set points and to read the current temperature.
0143
0144 It is also possible to say M here to build it as a module (ds1620)
0145 It is recommended to be used on a NetWinder, but it is not a
0146 necessity.
0147
0148 config NWBUTTON
0149 tristate "NetWinder Button"
0150 depends on ARCH_NETWINDER
0151 help
0152 If you say Y here and create a character device node /dev/nwbutton
0153 with major and minor numbers 10 and 158 ("man mknod"), then every
0154 time the orange button is pressed a number of times, the number of
0155 times the button was pressed will be written to that device.
0156
0157 This is most useful for applications, as yet unwritten, which
0158 perform actions based on how many times the button is pressed in a
0159 row.
0160
0161 Do not hold the button down for too long, as the driver does not
0162 alter the behaviour of the hardware reset circuitry attached to the
0163 button; it will still execute a hard reset if the button is held
0164 down for longer than approximately five seconds.
0165
0166 To compile this driver as a module, choose M here: the
0167 module will be called nwbutton.
0168
0169 Most people will answer Y to this question and "Reboot Using Button"
0170 below to be able to initiate a system shutdown from the button.
0171
0172 config NWBUTTON_REBOOT
0173 bool "Reboot Using Button"
0174 depends on NWBUTTON
0175 help
0176 If you say Y here, then you will be able to initiate a system
0177 shutdown and reboot by pressing the orange button a number of times.
0178 The number of presses to initiate the shutdown is two by default,
0179 but this can be altered by modifying the value of NUM_PRESSES_REBOOT
0180 in nwbutton.h and recompiling the driver or, if you compile the
0181 driver as a module, you can specify the number of presses at load
0182 time with "insmod button reboot_count=<something>".
0183
0184 config NWFLASH
0185 tristate "NetWinder flash support"
0186 depends on ARCH_NETWINDER
0187 help
0188 If you say Y here and create a character device /dev/flash with
0189 major 10 and minor 160 you can manipulate the flash ROM containing
0190 the NetWinder firmware. Be careful as accidentally overwriting the
0191 flash contents can render your computer unbootable. On no account
0192 allow random users access to this device. :-)
0193
0194 To compile this driver as a module, choose M here: the
0195 module will be called nwflash.
0196
0197 If you're not sure, say N.
0198
0199 source "drivers/char/hw_random/Kconfig"
0200
0201 config DTLK
0202 tristate "Double Talk PC internal speech card support"
0203 depends on ISA
0204 help
0205 This driver is for the DoubleTalk PC, a speech synthesizer
0206 manufactured by RC Systems (<https://www.rcsys.com/>). It is also
0207 called the `internal DoubleTalk'.
0208
0209 To compile this driver as a module, choose M here: the
0210 module will be called dtlk.
0211
0212 config XILINX_HWICAP
0213 tristate "Xilinx HWICAP Support"
0214 depends on MICROBLAZE
0215 help
0216 This option enables support for Xilinx Internal Configuration
0217 Access Port (ICAP) driver. The ICAP is used on Xilinx Virtex
0218 FPGA platforms to partially reconfigure the FPGA at runtime.
0219
0220 If unsure, say N.
0221
0222 config APPLICOM
0223 tristate "Applicom intelligent fieldbus card support"
0224 depends on PCI
0225 help
0226 This driver provides the kernel-side support for the intelligent
0227 fieldbus cards made by Applicom International. More information
0228 about these cards can be found on the WWW at the address
0229 <https://www.applicom-int.com/>, or by email from David Woodhouse
0230 <dwmw2@infradead.org>.
0231
0232 To compile this driver as a module, choose M here: the
0233 module will be called applicom.
0234
0235 If unsure, say N.
0236
0237 config SONYPI
0238 tristate "Sony Vaio Programmable I/O Control Device support"
0239 depends on X86_32 && PCI && INPUT
0240 help
0241 This driver enables access to the Sony Programmable I/O Control
0242 Device which can be found in many (all ?) Sony Vaio laptops.
0243
0244 If you have one of those laptops, read
0245 <file:Documentation/admin-guide/laptops/sonypi.rst>, and say Y or M here.
0246
0247 To compile this driver as a module, choose M here: the
0248 module will be called sonypi.
0249
0250 source "drivers/char/pcmcia/Kconfig"
0251
0252 config MWAVE
0253 tristate "ACP Modem (Mwave) support"
0254 depends on X86 && TTY
0255 select SERIAL_8250
0256 help
0257 The ACP modem (Mwave) for Linux is a WinModem. It is composed of a
0258 kernel driver and a user level application. Together these components
0259 support direct attachment to public switched telephone networks (PSTNs)
0260 and support selected world wide countries.
0261
0262 This version of the ACP Modem driver supports the IBM Thinkpad 600E,
0263 600, and 770 that include on board ACP modem hardware.
0264
0265 The modem also supports the standard communications port interface
0266 (ttySx) and is compatible with the Hayes AT Command Set.
0267
0268 The user level application needed to use this driver can be found at
0269 the IBM Linux Technology Center (LTC) web site:
0270 <http://www.ibm.com/linux/ltc/>.
0271
0272 If you own one of the above IBM Thinkpads which has the Mwave chipset
0273 in it, say Y.
0274
0275 To compile this driver as a module, choose M here: the
0276 module will be called mwave.
0277
0278 config SCx200_GPIO
0279 tristate "NatSemi SCx200 GPIO Support"
0280 depends on SCx200
0281 select NSC_GPIO
0282 help
0283 Give userspace access to the GPIO pins on the National
0284 Semiconductor SCx200 processors.
0285
0286 If compiled as a module, it will be called scx200_gpio.
0287
0288 config PC8736x_GPIO
0289 tristate "NatSemi PC8736x GPIO Support"
0290 depends on X86_32 && !UML
0291 default SCx200_GPIO # mostly N
0292 select NSC_GPIO # needed for support routines
0293 help
0294 Give userspace access to the GPIO pins on the National
0295 Semiconductor PC-8736x (x=[03456]) SuperIO chip. The chip
0296 has multiple functional units, inc several managed by
0297 hwmon/pc87360 driver. Tested with PC-87366
0298
0299 If compiled as a module, it will be called pc8736x_gpio.
0300
0301 config NSC_GPIO
0302 tristate "NatSemi Base GPIO Support"
0303 depends on X86_32
0304 # selected by SCx200_GPIO and PC8736x_GPIO
0305 # what about 2 selectors differing: m != y
0306 help
0307 Common support used (and needed) by scx200_gpio and
0308 pc8736x_gpio drivers. If those drivers are built as
0309 modules, this one will be too, named nsc_gpio
0310
0311 config DEVMEM
0312 bool "/dev/mem virtual device support"
0313 default y
0314 help
0315 Say Y here if you want to support the /dev/mem device.
0316 The /dev/mem device is used to access areas of physical
0317 memory.
0318 When in doubt, say "Y".
0319
0320 config NVRAM
0321 tristate "/dev/nvram support"
0322 depends on X86 || HAVE_ARCH_NVRAM_OPS
0323 default M68K || PPC
0324 help
0325 If you say Y here and create a character special file /dev/nvram
0326 with major number 10 and minor number 144 using mknod ("man mknod"),
0327 you get read and write access to the non-volatile memory.
0328
0329 /dev/nvram may be used to view settings in NVRAM or to change them
0330 (with some utility). It could also be used to frequently
0331 save a few bits of very important data that may not be lost over
0332 power-off and for which writing to disk is too insecure. Note
0333 however that most NVRAM space in a PC belongs to the BIOS and you
0334 should NEVER idly tamper with it. See Ralf Brown's interrupt list
0335 for a guide to the use of CMOS bytes by your BIOS.
0336
0337 This memory is conventionally called "NVRAM" on PowerPC machines,
0338 "CMOS RAM" on PCs, "NVRAM" on Ataris and "PRAM" on Macintoshes.
0339
0340 To compile this driver as a module, choose M here: the
0341 module will be called nvram.
0342
0343 config DEVPORT
0344 bool "/dev/port character device"
0345 depends on ISA || PCI
0346 default y
0347 help
0348 Say Y here if you want to support the /dev/port device. The /dev/port
0349 device is similar to /dev/mem, but for I/O ports.
0350
0351 config HPET
0352 bool "HPET - High Precision Event Timer" if (X86 || IA64)
0353 default n
0354 depends on ACPI
0355 help
0356 If you say Y here, you will have a miscdevice named "/dev/hpet/". Each
0357 open selects one of the timers supported by the HPET. The timers are
0358 non-periodic and/or periodic.
0359
0360 config HPET_MMAP
0361 bool "Allow mmap of HPET"
0362 default y
0363 depends on HPET
0364 help
0365 If you say Y here, user applications will be able to mmap
0366 the HPET registers.
0367
0368 config HPET_MMAP_DEFAULT
0369 bool "Enable HPET MMAP access by default"
0370 default y
0371 depends on HPET_MMAP
0372 help
0373 In some hardware implementations, the page containing HPET
0374 registers may also contain other things that shouldn't be
0375 exposed to the user. This option selects the default (if
0376 kernel parameter hpet_mmap is not set) user access to the
0377 registers for applications that require it.
0378
0379 config HANGCHECK_TIMER
0380 tristate "Hangcheck timer"
0381 depends on X86 || IA64 || PPC64 || S390
0382 help
0383 The hangcheck-timer module detects when the system has gone
0384 out to lunch past a certain margin. It can reboot the system
0385 or merely print a warning.
0386
0387 config UV_MMTIMER
0388 tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
0389 depends on X86_UV
0390 default m
0391 help
0392 The uv_mmtimer device allows direct userspace access to the
0393 UV system timer.
0394
0395 source "drivers/char/tpm/Kconfig"
0396
0397 config TELCLOCK
0398 tristate "Telecom clock driver for ATCA SBC"
0399 depends on X86
0400 default n
0401 help
0402 The telecom clock device is specific to the MPCBL0010 and MPCBL0050
0403 ATCA computers and allows direct userspace access to the
0404 configuration of the telecom clock configuration settings. This
0405 device is used for hardware synchronization across the ATCA backplane
0406 fabric. Upon loading, the driver exports a sysfs directory,
0407 /sys/devices/platform/telco_clock, with a number of files for
0408 controlling the behavior of this hardware.
0409
0410 source "drivers/s390/char/Kconfig"
0411
0412 source "drivers/char/xillybus/Kconfig"
0413
0414 config ADI
0415 tristate "SPARC Privileged ADI driver"
0416 depends on SPARC64
0417 default m
0418 help
0419 SPARC M7 and newer processors utilize ADI (Application Data
0420 Integrity) to version and protect memory. This driver provides
0421 read/write access to the ADI versions for privileged processes.
0422 This feature is also known as MCD (Memory Corruption Detection)
0423 and SSM (Silicon Secured Memory). Intended consumers of this
0424 driver include crash and makedumpfile.
0425
0426 config RANDOM_TRUST_CPU
0427 bool "Initialize RNG using CPU RNG instructions"
0428 default y
0429 help
0430 Initialize the RNG using random numbers supplied by the CPU's
0431 RNG instructions (e.g. RDRAND), if supported and available. These
0432 random numbers are never used directly, but are rather hashed into
0433 the main input pool, and this happens regardless of whether or not
0434 this option is enabled. Instead, this option controls whether the
0435 they are credited and hence can initialize the RNG. Additionally,
0436 other sources of randomness are always used, regardless of this
0437 setting. Enabling this implies trusting that the CPU can supply high
0438 quality and non-backdoored random numbers.
0439
0440 Say Y here unless you have reason to mistrust your CPU or believe
0441 its RNG facilities may be faulty. This may also be configured at
0442 boot time with "random.trust_cpu=on/off".
0443
0444 config RANDOM_TRUST_BOOTLOADER
0445 bool "Initialize RNG using bootloader-supplied seed"
0446 default y
0447 help
0448 Initialize the RNG using a seed supplied by the bootloader or boot
0449 environment (e.g. EFI or a bootloader-generated device tree). This
0450 seed is not used directly, but is rather hashed into the main input
0451 pool, and this happens regardless of whether or not this option is
0452 enabled. Instead, this option controls whether the seed is credited
0453 and hence can initialize the RNG. Additionally, other sources of
0454 randomness are always used, regardless of this setting. Enabling
0455 this implies trusting that the bootloader can supply high quality and
0456 non-backdoored seeds.
0457
0458 Say Y here unless you have reason to mistrust your bootloader or
0459 believe its RNG facilities may be faulty. This may also be configured
0460 at boot time with "random.trust_bootloader=on/off".
0461
0462 endmenu
