drivers/char/Kconfig

   1 # SPDX-License-Identifier: GPL-2.0
   2 #
   3 # Character device configuration
   4 #
   5
   6 menu "Character devices"
   7
   8 source "drivers/tty/Kconfig"
   9
  10 config TTY_PRINTK
  11         tristate "TTY driver to output user messages via printk"
  12         depends on EXPERT && TTY
  13         default n
  14         help
  15           If you say Y here, the support for writing user messages (i.e.
  16           console messages) via printk is available.
  17
  18           The feature is useful to inline user messages with kernel
  19           messages.
  20           In order to use this feature, you should output user messages
  21           to /dev/ttyprintk or redirect console to this TTY.
  22
  23           If unsure, say N.
  24
  25 config TTY_PRINTK_LEVEL
  26         depends on TTY_PRINTK
  27         int "ttyprintk log level (1-7)"
  28         range 1 7
  29         default "6"
  30         help
  31           Printk log level to use for ttyprintk messages.
  32
  33 config PRINTER
  34         tristate "Parallel printer support"
  35         depends on PARPORT
  36         help
  37           If you intend to attach a printer to the parallel port of your Linux
  38           box (as opposed to using a serial printer; if the connector at the
  39           printer has 9 or 25 holes ["female"], then it's serial), say Y.
  40           Also read the Printing-HOWTO, available from
  41           <https://www.tldp.org/docs.html#howto>.
  42
  43           It is possible to share one parallel port among several devices
  44           (e.g. printer and ZIP drive) and it is safe to compile the
  45           corresponding drivers into the kernel.
  46
  47           To compile this driver as a module, choose M here and read
  48           <file:Documentation/admin-guide/parport.rst>.  The module will be called lp.
  49
  50           If you have several parallel ports, you can specify which ports to
  51           use with the "lp" kernel command line option.  (Try "man bootparam"
  52           or see the documentation of your boot loader (lilo or loadlin) about
  53           how to pass options to the kernel at boot time.)  The syntax of the
  54           "lp" command line option can be found in <file:drivers/char/lp.c>.
  55
  56           If you have more than 8 printers, you need to increase the LP_NO
  57           macro in lp.c and the PARPORT_MAX macro in parport.h.
  58
  59 config LP_CONSOLE
  60         bool "Support for console on line printer"
  61         depends on PRINTER
  62         help
  63           If you want kernel messages to be printed out as they occur, you
  64           can have a console on the printer. This option adds support for
  65           doing that; to actually get it to happen you need to pass the
  66           option "console=lp0" to the kernel at boot time.
  67
  68           If the printer is out of paper (or off, or unplugged, or too
  69           busy..) the kernel will stall until the printer is ready again.
  70           By defining CONSOLE_LP_STRICT to 0 (at your own risk) you
  71           can make the kernel continue when this happens,
  72           but it'll lose the kernel messages.
  73
  74           If unsure, say N.
  75
  76 config PPDEV
  77         tristate "Support for user-space parallel port device drivers"
  78         depends on PARPORT
  79         help
  80           Saying Y to this adds support for /dev/parport device nodes.  This
  81           is needed for programs that want portable access to the parallel
  82           port, for instance deviceid (which displays Plug-and-Play device
  83           IDs).
  84
  85           This is the parallel port equivalent of SCSI generic support (sg).
  86           It is safe to say N to this -- it is not needed for normal printing
  87           or parallel port CD-ROM/disk support.
  88
  89           To compile this driver as a module, choose M here: the
  90           module will be called ppdev.
  91
  92           If unsure, say N.
  93
  94 config VIRTIO_CONSOLE
  95         tristate "Virtio console"
  96         depends on TTY
  97         select HVC_DRIVER
  98         select VIRTIO
  99         help
 100           Virtio console for use with hypervisors.
 101
 102           Also serves as a general-purpose serial device for data
 103           transfer between the guest and host.  Character devices at
 104           /dev/vportNpn will be created when corresponding ports are
 105           found, where N is the device number and n is the port number
 106           within that device.  If specified by the host, a sysfs
 107           attribute called 'name' will be populated with a name for
 108           the port which can be used by udev scripts to create a
 109           symlink to the device.
 110
 111 config IBM_BSR
 112         tristate "IBM POWER Barrier Synchronization Register support"
 113         depends on PPC_PSERIES
 114         help
 115           This devices exposes a hardware mechanism for fast synchronization
 116           of threads across a large system which avoids bouncing a cacheline
 117           between several cores on a system
 118
 119 config POWERNV_OP_PANEL
 120         tristate "IBM POWERNV Operator Panel Display support"
 121         depends on PPC_POWERNV
 122         default m
 123         help
 124           If you say Y here, a special character device node, /dev/op_panel,
 125           will be created which exposes the operator panel display on IBM
 126           Power Systems machines with FSPs.
 127
 128           If you don't require access to the operator panel display from user
 129           space, say N.
 130
 131           If unsure, say M here to build it as a module called powernv-op-panel.
 132
 133 source "drivers/char/ipmi/Kconfig"
 134
 135 config DS1620
 136         tristate "NetWinder thermometer support"
 137         depends on ARCH_NETWINDER
 138         help
 139           Say Y here to include support for the thermal management hardware
 140           found in the NetWinder. This driver allows the user to control the
 141           temperature set points and to read the current temperature.
 142
 143           It is also possible to say M here to build it as a module (ds1620)
 144           It is recommended to be used on a NetWinder, but it is not a
 145           necessity.
 146
 147 config NWBUTTON
 148         tristate "NetWinder Button"
 149         depends on ARCH_NETWINDER
 150         help
 151           If you say Y here and create a character device node /dev/nwbutton
 152           with major and minor numbers 10 and 158 ("man mknod"), then every
 153           time the orange button is pressed a number of times, the number of
 154           times the button was pressed will be written to that device.
 155
 156           This is most useful for applications, as yet unwritten, which
 157           perform actions based on how many times the button is pressed in a
 158           row.
 159
 160           Do not hold the button down for too long, as the driver does not
 161           alter the behaviour of the hardware reset circuitry attached to the
 162           button; it will still execute a hard reset if the button is held
 163           down for longer than approximately five seconds.
 164
 165           To compile this driver as a module, choose M here: the
 166           module will be called nwbutton.
 167
 168           Most people will answer Y to this question and "Reboot Using Button"
 169           below to be able to initiate a system shutdown from the button.
 170
 171 config NWBUTTON_REBOOT
 172         bool "Reboot Using Button"
 173         depends on NWBUTTON
 174         help
 175           If you say Y here, then you will be able to initiate a system
 176           shutdown and reboot by pressing the orange button a number of times.
 177           The number of presses to initiate the shutdown is two by default,
 178           but this can be altered by modifying the value of NUM_PRESSES_REBOOT
 179           in nwbutton.h and recompiling the driver or, if you compile the
 180           driver as a module, you can specify the number of presses at load
 181           time with "insmod button reboot_count=<something>".
 182
 183 config NWFLASH
 184         tristate "NetWinder flash support"
 185         depends on ARCH_NETWINDER
 186         help
 187           If you say Y here and create a character device /dev/flash with
 188           major 10 and minor 160 you can manipulate the flash ROM containing
 189           the NetWinder firmware. Be careful as accidentally overwriting the
 190           flash contents can render your computer unbootable. On no account
 191           allow random users access to this device. :-)
 192
 193           To compile this driver as a module, choose M here: the
 194           module will be called nwflash.
 195
 196           If you're not sure, say N.
 197
 198 source "drivers/char/hw_random/Kconfig"
 199
 200 config DTLK
 201         tristate "Double Talk PC internal speech card support"
 202         depends on ISA
 203         help
 204           This driver is for the DoubleTalk PC, a speech synthesizer
 205           manufactured by RC Systems (<https://www.rcsys.com/>).  It is also
 206           called the `internal DoubleTalk'.
 207
 208           To compile this driver as a module, choose M here: the
 209           module will be called dtlk.
 210
 211 config XILINX_HWICAP
 212         tristate "Xilinx HWICAP Support"
 213         depends on MICROBLAZE
 214         help
 215           This option enables support for Xilinx Internal Configuration
 216           Access Port (ICAP) driver.  The ICAP is used on Xilinx Virtex
 217           FPGA platforms to partially reconfigure the FPGA at runtime.
 218
 219           If unsure, say N.
 220
 221 config APPLICOM
 222         tristate "Applicom intelligent fieldbus card support"
 223         depends on PCI
 224         help
 225           This driver provides the kernel-side support for the intelligent
 226           fieldbus cards made by Applicom International. More information
 227           about these cards can be found on the WWW at the address
 228           <https://www.applicom-int.com/>, or by email from David Woodhouse
 229           <dwmw2@infradead.org>.
 230
 231           To compile this driver as a module, choose M here: the
 232           module will be called applicom.
 233
 234           If unsure, say N.
 235
 236 config SONYPI
 237         tristate "Sony Vaio Programmable I/O Control Device support"
 238         depends on X86_32 && PCI && INPUT
 239         help
 240           This driver enables access to the Sony Programmable I/O Control
 241           Device which can be found in many (all ?) Sony Vaio laptops.
 242
 243           If you have one of those laptops, read
 244           <file:Documentation/admin-guide/laptops/sonypi.rst>, and say Y or M here.
 245
 246           To compile this driver as a module, choose M here: the
 247           module will be called sonypi.
 248
 249 config GPIO_TB0219
 250         tristate "TANBAC TB0219 GPIO support"
 251         depends on TANBAC_TB022X
 252         select GPIO_VR41XX
 253
 254 source "drivers/char/pcmcia/Kconfig"
 255
 256 config MWAVE
 257         tristate "ACP Modem (Mwave) support"
 258         depends on X86 && TTY
 259         select SERIAL_8250
 260         help
 261           The ACP modem (Mwave) for Linux is a WinModem. It is composed of a
 262           kernel driver and a user level application. Together these components
 263           support direct attachment to public switched telephone networks (PSTNs)
 264           and support selected world wide countries.
 265
 266           This version of the ACP Modem driver supports the IBM Thinkpad 600E,
 267           600, and 770 that include on board ACP modem hardware.
 268
 269           The modem also supports the standard communications port interface
 270           (ttySx) and is compatible with the Hayes AT Command Set.
 271
 272           The user level application needed to use this driver can be found at
 273           the IBM Linux Technology Center (LTC) web site:
 274           <http://www.ibm.com/linux/ltc/>.
 275
 276           If you own one of the above IBM Thinkpads which has the Mwave chipset
 277           in it, say Y.
 278
 279           To compile this driver as a module, choose M here: the
 280           module will be called mwave.
 281
 282 config SCx200_GPIO
 283         tristate "NatSemi SCx200 GPIO Support"
 284         depends on SCx200
 285         select NSC_GPIO
 286         help
 287           Give userspace access to the GPIO pins on the National
 288           Semiconductor SCx200 processors.
 289
 290           If compiled as a module, it will be called scx200_gpio.
 291
 292 config PC8736x_GPIO
 293         tristate "NatSemi PC8736x GPIO Support"
 294         depends on X86_32 && !UML
 295         default SCx200_GPIO     # mostly N
 296         select NSC_GPIO         # needed for support routines
 297         help
 298           Give userspace access to the GPIO pins on the National
 299           Semiconductor PC-8736x (x=[03456]) SuperIO chip.  The chip
 300           has multiple functional units, inc several managed by
 301           hwmon/pc87360 driver.  Tested with PC-87366
 302
 303           If compiled as a module, it will be called pc8736x_gpio.
 304
 305 config NSC_GPIO
 306         tristate "NatSemi Base GPIO Support"
 307         depends on X86_32
 308         # selected by SCx200_GPIO and PC8736x_GPIO
 309         # what about 2 selectors differing: m != y
 310         help
 311           Common support used (and needed) by scx200_gpio and
 312           pc8736x_gpio drivers.  If those drivers are built as
 313           modules, this one will be too, named nsc_gpio
 314
 315 config DEVMEM
 316         bool "/dev/mem virtual device support"
 317         default y
 318         help
 319           Say Y here if you want to support the /dev/mem device.
 320           The /dev/mem device is used to access areas of physical
 321           memory.
 322           When in doubt, say "Y".
 323
 324 config NVRAM
 325         tristate "/dev/nvram support"
 326         depends on X86 || HAVE_ARCH_NVRAM_OPS
 327         default M68K || PPC
 328         help
 329           If you say Y here and create a character special file /dev/nvram
 330           with major number 10 and minor number 144 using mknod ("man mknod"),
 331           you get read and write access to the non-volatile memory.
 332
 333           /dev/nvram may be used to view settings in NVRAM or to change them
 334           (with some utility). It could also be used to frequently
 335           save a few bits of very important data that may not be lost over
 336           power-off and for which writing to disk is too insecure. Note
 337           however that most NVRAM space in a PC belongs to the BIOS and you
 338           should NEVER idly tamper with it. See Ralf Brown's interrupt list
 339           for a guide to the use of CMOS bytes by your BIOS.
 340
 341           This memory is conventionally called "NVRAM" on PowerPC machines,
 342           "CMOS RAM" on PCs, "NVRAM" on Ataris and "PRAM" on Macintoshes.
 343
 344           To compile this driver as a module, choose M here: the
 345           module will be called nvram.
 346
 347 config DEVPORT
 348         bool "/dev/port character device"
 349         depends on ISA || PCI
 350         default y
 351         help
 352           Say Y here if you want to support the /dev/port device. The /dev/port
 353           device is similar to /dev/mem, but for I/O ports.
 354
 355 config HPET
 356         bool "HPET - High Precision Event Timer" if (X86 || IA64)
 357         default n
 358         depends on ACPI
 359         help
 360           If you say Y here, you will have a miscdevice named "/dev/hpet/".  Each
 361           open selects one of the timers supported by the HPET.  The timers are
 362           non-periodic and/or periodic.
 363
 364 config HPET_MMAP
 365         bool "Allow mmap of HPET"
 366         default y
 367         depends on HPET
 368         help
 369           If you say Y here, user applications will be able to mmap
 370           the HPET registers.
 371
 372 config HPET_MMAP_DEFAULT
 373         bool "Enable HPET MMAP access by default"
 374         default y
 375         depends on HPET_MMAP
 376         help
 377           In some hardware implementations, the page containing HPET
 378           registers may also contain other things that shouldn't be
 379           exposed to the user.  This option selects the default (if
 380           kernel parameter hpet_mmap is not set) user access to the
 381           registers for applications that require it.
 382
 383 config HANGCHECK_TIMER
 384         tristate "Hangcheck timer"
 385         depends on X86 || IA64 || PPC64 || S390
 386         help
 387           The hangcheck-timer module detects when the system has gone
 388           out to lunch past a certain margin.  It can reboot the system
 389           or merely print a warning.
 390
 391 config UV_MMTIMER
 392         tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
 393         depends on X86_UV
 394         default m
 395         help
 396           The uv_mmtimer device allows direct userspace access to the
 397           UV system timer.
 398
 399 source "drivers/char/tpm/Kconfig"
 400
 401 config TELCLOCK
 402         tristate "Telecom clock driver for ATCA SBC"
 403         depends on X86
 404         default n
 405         help
 406           The telecom clock device is specific to the MPCBL0010 and MPCBL0050
 407           ATCA computers and allows direct userspace access to the
 408           configuration of the telecom clock configuration settings.  This
 409           device is used for hardware synchronization across the ATCA backplane
 410           fabric.  Upon loading, the driver exports a sysfs directory,
 411           /sys/devices/platform/telco_clock, with a number of files for
 412           controlling the behavior of this hardware.
 413
 414 source "drivers/s390/char/Kconfig"
 415
 416 source "drivers/char/xillybus/Kconfig"
 417
 418 config ADI
 419         tristate "SPARC Privileged ADI driver"
 420         depends on SPARC64
 421         default m
 422         help
 423           SPARC M7 and newer processors utilize ADI (Application Data
 424           Integrity) to version and protect memory.  This driver provides
 425           read/write access to the ADI versions for privileged processes.
 426           This feature is also known as MCD (Memory Corruption Detection)
 427           and SSM (Silicon Secured Memory).  Intended consumers of this
 428           driver include crash and makedumpfile.
 429
 430 config RANDOM_TRUST_CPU
 431         bool "Trust the CPU manufacturer to initialize Linux's CRNG"
 432         depends on ARCH_RANDOM
 433         default n
 434         help
 435         Assume that CPU manufacturer (e.g., Intel or AMD for RDSEED or
 436         RDRAND, IBM for the S390 and Power PC architectures) is trustworthy
 437         for the purposes of initializing Linux's CRNG.  Since this is not
 438         something that can be independently audited, this amounts to trusting
 439         that CPU manufacturer (perhaps with the insistence or mandate
 440         of a Nation State's intelligence or law enforcement agencies)
 441         has not installed a hidden back door to compromise the CPU's
 442         random number generation facilities. This can also be configured
 443         at boot with "random.trust_cpu=on/off".
 444
 445 config RANDOM_TRUST_BOOTLOADER
 446         bool "Trust the bootloader to initialize Linux's CRNG"
 447         help
 448         Some bootloaders can provide entropy to increase the kernel's initial
 449         device randomness. Say Y here to assume the entropy provided by the
 450         booloader is trustworthy so it will be added to the kernel's entropy
 451         pool. Otherwise, say N here so it will be regarded as device input that
 452         only mixes the entropy pool.
 453
 454 endmenu