1# SPDX-License-Identifier: GPL-2.0 2# 3# Character device configuration 4# 5 6menu "Character devices" 7 8source "drivers/tty/Kconfig" 9 10config 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, or boot 22 the kernel with console=ttyprintk. 23 24 If unsure, say N. 25 26config TTY_PRINTK_LEVEL 27 depends on TTY_PRINTK 28 int "ttyprintk log level (1-7)" 29 range 1 7 30 default "6" 31 help 32 Printk log level to use for ttyprintk messages. 33 34config PRINTER 35 tristate "Parallel printer support" 36 depends on PARPORT 37 help 38 If you intend to attach a printer to the parallel port of your Linux 39 box (as opposed to using a serial printer; if the connector at the 40 printer has 9 or 25 holes ["female"], then it's serial), say Y. 41 Also read the Printing-HOWTO, available from 42 <https://www.tldp.org/docs.html#howto>. 43 44 It is possible to share one parallel port among several devices 45 (e.g. printer and ZIP drive) and it is safe to compile the 46 corresponding drivers into the kernel. 47 48 To compile this driver as a module, choose M here and read 49 <file:Documentation/admin-guide/parport.rst>. The module will be called lp. 50 51 If you have several parallel ports, you can specify which ports to 52 use with the "lp" kernel command line option. (Try "man bootparam" 53 or see the documentation of your boot loader (lilo or loadlin) about 54 how to pass options to the kernel at boot time.) The syntax of the 55 "lp" command line option can be found in <file:drivers/char/lp.c>. 56 57 If you have more than 8 printers, you need to increase the LP_NO 58 macro in lp.c and the PARPORT_MAX macro in parport.h. 59 60config LP_CONSOLE 61 bool "Support for console on line printer" 62 depends on PRINTER 63 help 64 If you want kernel messages to be printed out as they occur, you 65 can have a console on the printer. This option adds support for 66 doing that; to actually get it to happen you need to pass the 67 option "console=lp0" to the kernel at boot time. 68 69 If the printer is out of paper (or off, or unplugged, or too 70 busy..) the kernel will stall until the printer is ready again. 71 By defining CONSOLE_LP_STRICT to 0 (at your own risk) you 72 can make the kernel continue when this happens, 73 but it'll lose the kernel messages. 74 75 If unsure, say N. 76 77config PPDEV 78 tristate "Support for user-space parallel port device drivers" 79 depends on PARPORT 80 help 81 Saying Y to this adds support for /dev/parport device nodes. This 82 is needed for programs that want portable access to the parallel 83 port, for instance deviceid (which displays Plug-and-Play device 84 IDs). 85 86 This is the parallel port equivalent of SCSI generic support (sg). 87 It is safe to say N to this -- it is not needed for normal printing 88 or parallel port CD-ROM/disk support. 89 90 To compile this driver as a module, choose M here: the 91 module will be called ppdev. 92 93 If unsure, say N. 94 95config VIRTIO_CONSOLE 96 tristate "Virtio console" 97 depends on TTY 98 select HVC_DRIVER 99 select VIRTIO 100 help 101 Virtio console for use with hypervisors. 102 103 Also serves as a general-purpose serial device for data 104 transfer between the guest and host. Character devices at 105 /dev/vportNpn will be created when corresponding ports are 106 found, where N is the device number and n is the port number 107 within that device. If specified by the host, a sysfs 108 attribute called 'name' will be populated with a name for 109 the port which can be used by udev scripts to create a 110 symlink to the device. 111 112config IBM_BSR 113 tristate "IBM POWER Barrier Synchronization Register support" 114 depends on PPC_PSERIES 115 help 116 This devices exposes a hardware mechanism for fast synchronization 117 of threads across a large system which avoids bouncing a cacheline 118 between several cores on a system 119 120config POWERNV_OP_PANEL 121 tristate "IBM POWERNV Operator Panel Display support" 122 depends on PPC_POWERNV 123 default m 124 help 125 If you say Y here, a special character device node, /dev/op_panel, 126 will be created which exposes the operator panel display on IBM 127 Power Systems machines with FSPs. 128 129 If you don't require access to the operator panel display from user 130 space, say N. 131 132 If unsure, say M here to build it as a module called powernv-op-panel. 133 134source "drivers/char/ipmi/Kconfig" 135 136config DS1620 137 tristate "NetWinder thermometer support" 138 depends on ARCH_NETWINDER 139 help 140 Say Y here to include support for the thermal management hardware 141 found in the NetWinder. This driver allows the user to control the 142 temperature set points and to read the current temperature. 143 144 It is also possible to say M here to build it as a module (ds1620) 145 It is recommended to be used on a NetWinder, but it is not a 146 necessity. 147 148config NWBUTTON 149 tristate "NetWinder Button" 150 depends on ARCH_NETWINDER 151 help 152 If you say Y here and create a character device node /dev/nwbutton 153 with major and minor numbers 10 and 158 ("man mknod"), then every 154 time the orange button is pressed a number of times, the number of 155 times the button was pressed will be written to that device. 156 157 This is most useful for applications, as yet unwritten, which 158 perform actions based on how many times the button is pressed in a 159 row. 160 161 Do not hold the button down for too long, as the driver does not 162 alter the behaviour of the hardware reset circuitry attached to the 163 button; it will still execute a hard reset if the button is held 164 down for longer than approximately five seconds. 165 166 To compile this driver as a module, choose M here: the 167 module will be called nwbutton. 168 169 Most people will answer Y to this question and "Reboot Using Button" 170 below to be able to initiate a system shutdown from the button. 171 172config NWBUTTON_REBOOT 173 bool "Reboot Using Button" 174 depends on NWBUTTON 175 help 176 If you say Y here, then you will be able to initiate a system 177 shutdown and reboot by pressing the orange button a number of times. 178 The number of presses to initiate the shutdown is two by default, 179 but this can be altered by modifying the value of NUM_PRESSES_REBOOT 180 in nwbutton.h and recompiling the driver or, if you compile the 181 driver as a module, you can specify the number of presses at load 182 time with "insmod button reboot_count=<something>". 183 184config NWFLASH 185 tristate "NetWinder flash support" 186 depends on ARCH_NETWINDER 187 help 188 If you say Y here and create a character device /dev/flash with 189 major 10 and minor 160 you can manipulate the flash ROM containing 190 the NetWinder firmware. Be careful as accidentally overwriting the 191 flash contents can render your computer unbootable. On no account 192 allow random users access to this device. :-) 193 194 To compile this driver as a module, choose M here: the 195 module will be called nwflash. 196 197 If you're not sure, say N. 198 199source "drivers/char/hw_random/Kconfig" 200 201config DTLK 202 tristate "Double Talk PC internal speech card support" 203 depends on ISA 204 help 205 This driver is for the DoubleTalk PC, a speech synthesizer 206 manufactured by RC Systems (<https://www.rcsys.com/>). It is also 207 called the `internal DoubleTalk'. 208 209 To compile this driver as a module, choose M here: the 210 module will be called dtlk. 211 212config XILINX_HWICAP 213 tristate "Xilinx HWICAP Support" 214 depends on MICROBLAZE 215 help 216 This option enables support for Xilinx Internal Configuration 217 Access Port (ICAP) driver. The ICAP is used on Xilinx Virtex 218 FPGA platforms to partially reconfigure the FPGA at runtime. 219 220 If unsure, say N. 221 222config APPLICOM 223 tristate "Applicom intelligent fieldbus card support" 224 depends on PCI 225 help 226 This driver provides the kernel-side support for the intelligent 227 fieldbus cards made by Applicom International. More information 228 about these cards can be found on the WWW at the address 229 <https://www.applicom-int.com/>, or by email from David Woodhouse 230 <dwmw2@infradead.org>. 231 232 To compile this driver as a module, choose M here: the 233 module will be called applicom. 234 235 If unsure, say N. 236 237config SONYPI 238 tristate "Sony Vaio Programmable I/O Control Device support" 239 depends on X86_32 && PCI && INPUT 240 help 241 This driver enables access to the Sony Programmable I/O Control 242 Device which can be found in many (all ?) Sony Vaio laptops. 243 244 If you have one of those laptops, read 245 <file:Documentation/admin-guide/laptops/sonypi.rst>, and say Y or M here. 246 247 To compile this driver as a module, choose M here: the 248 module will be called sonypi. 249 250config GPIO_TB0219 251 tristate "TANBAC TB0219 GPIO support" 252 depends on TANBAC_TB022X 253 select GPIO_VR41XX 254 255source "drivers/char/pcmcia/Kconfig" 256 257config MWAVE 258 tristate "ACP Modem (Mwave) support" 259 depends on X86 && TTY 260 select SERIAL_8250 261 help 262 The ACP modem (Mwave) for Linux is a WinModem. It is composed of a 263 kernel driver and a user level application. Together these components 264 support direct attachment to public switched telephone networks (PSTNs) 265 and support selected world wide countries. 266 267 This version of the ACP Modem driver supports the IBM Thinkpad 600E, 268 600, and 770 that include on board ACP modem hardware. 269 270 The modem also supports the standard communications port interface 271 (ttySx) and is compatible with the Hayes AT Command Set. 272 273 The user level application needed to use this driver can be found at 274 the IBM Linux Technology Center (LTC) web site: 275 <http://www.ibm.com/linux/ltc/>. 276 277 If you own one of the above IBM Thinkpads which has the Mwave chipset 278 in it, say Y. 279 280 To compile this driver as a module, choose M here: the 281 module will be called mwave. 282 283config SCx200_GPIO 284 tristate "NatSemi SCx200 GPIO Support" 285 depends on SCx200 286 select NSC_GPIO 287 help 288 Give userspace access to the GPIO pins on the National 289 Semiconductor SCx200 processors. 290 291 If compiled as a module, it will be called scx200_gpio. 292 293config PC8736x_GPIO 294 tristate "NatSemi PC8736x GPIO Support" 295 depends on X86_32 && !UML 296 default SCx200_GPIO # mostly N 297 select NSC_GPIO # needed for support routines 298 help 299 Give userspace access to the GPIO pins on the National 300 Semiconductor PC-8736x (x=[03456]) SuperIO chip. The chip 301 has multiple functional units, inc several managed by 302 hwmon/pc87360 driver. Tested with PC-87366 303 304 If compiled as a module, it will be called pc8736x_gpio. 305 306config NSC_GPIO 307 tristate "NatSemi Base GPIO Support" 308 depends on X86_32 309 # selected by SCx200_GPIO and PC8736x_GPIO 310 # what about 2 selectors differing: m != y 311 help 312 Common support used (and needed) by scx200_gpio and 313 pc8736x_gpio drivers. If those drivers are built as 314 modules, this one will be too, named nsc_gpio 315 316config DEVMEM 317 bool "/dev/mem virtual device support" 318 default y 319 help 320 Say Y here if you want to support the /dev/mem device. 321 The /dev/mem device is used to access areas of physical 322 memory. 323 When in doubt, say "Y". 324 325config NVRAM 326 tristate "/dev/nvram support" 327 depends on X86 || HAVE_ARCH_NVRAM_OPS 328 default M68K || PPC 329 help 330 If you say Y here and create a character special file /dev/nvram 331 with major number 10 and minor number 144 using mknod ("man mknod"), 332 you get read and write access to the non-volatile memory. 333 334 /dev/nvram may be used to view settings in NVRAM or to change them 335 (with some utility). It could also be used to frequently 336 save a few bits of very important data that may not be lost over 337 power-off and for which writing to disk is too insecure. Note 338 however that most NVRAM space in a PC belongs to the BIOS and you 339 should NEVER idly tamper with it. See Ralf Brown's interrupt list 340 for a guide to the use of CMOS bytes by your BIOS. 341 342 This memory is conventionally called "NVRAM" on PowerPC machines, 343 "CMOS RAM" on PCs, "NVRAM" on Ataris and "PRAM" on Macintoshes. 344 345 To compile this driver as a module, choose M here: the 346 module will be called nvram. 347 348config DEVPORT 349 bool "/dev/port character device" 350 depends on ISA || PCI 351 default y 352 help 353 Say Y here if you want to support the /dev/port device. The /dev/port 354 device is similar to /dev/mem, but for I/O ports. 355 356config HPET 357 bool "HPET - High Precision Event Timer" if (X86 || IA64) 358 default n 359 depends on ACPI 360 help 361 If you say Y here, you will have a miscdevice named "/dev/hpet/". Each 362 open selects one of the timers supported by the HPET. The timers are 363 non-periodic and/or periodic. 364 365config HPET_MMAP 366 bool "Allow mmap of HPET" 367 default y 368 depends on HPET 369 help 370 If you say Y here, user applications will be able to mmap 371 the HPET registers. 372 373config HPET_MMAP_DEFAULT 374 bool "Enable HPET MMAP access by default" 375 default y 376 depends on HPET_MMAP 377 help 378 In some hardware implementations, the page containing HPET 379 registers may also contain other things that shouldn't be 380 exposed to the user. This option selects the default (if 381 kernel parameter hpet_mmap is not set) user access to the 382 registers for applications that require it. 383 384config HANGCHECK_TIMER 385 tristate "Hangcheck timer" 386 depends on X86 || IA64 || PPC64 || S390 387 help 388 The hangcheck-timer module detects when the system has gone 389 out to lunch past a certain margin. It can reboot the system 390 or merely print a warning. 391 392config UV_MMTIMER 393 tristate "UV_MMTIMER Memory mapped RTC for SGI UV" 394 depends on X86_UV 395 default m 396 help 397 The uv_mmtimer device allows direct userspace access to the 398 UV system timer. 399 400source "drivers/char/tpm/Kconfig" 401 402config TELCLOCK 403 tristate "Telecom clock driver for ATCA SBC" 404 depends on X86 405 default n 406 help 407 The telecom clock device is specific to the MPCBL0010 and MPCBL0050 408 ATCA computers and allows direct userspace access to the 409 configuration of the telecom clock configuration settings. This 410 device is used for hardware synchronization across the ATCA backplane 411 fabric. Upon loading, the driver exports a sysfs directory, 412 /sys/devices/platform/telco_clock, with a number of files for 413 controlling the behavior of this hardware. 414 415source "drivers/s390/char/Kconfig" 416 417source "drivers/char/xillybus/Kconfig" 418 419config ADI 420 tristate "SPARC Privileged ADI driver" 421 depends on SPARC64 422 default m 423 help 424 SPARC M7 and newer processors utilize ADI (Application Data 425 Integrity) to version and protect memory. This driver provides 426 read/write access to the ADI versions for privileged processes. 427 This feature is also known as MCD (Memory Corruption Detection) 428 and SSM (Silicon Secured Memory). Intended consumers of this 429 driver include crash and makedumpfile. 430 431config RANDOM_TRUST_CPU 432 bool "Initialize RNG using CPU RNG instructions" 433 default y 434 depends on ARCH_RANDOM 435 help 436 Initialize the RNG using random numbers supplied by the CPU's 437 RNG instructions (e.g. RDRAND), if supported and available. These 438 random numbers are never used directly, but are rather hashed into 439 the main input pool, and this happens regardless of whether or not 440 this option is enabled. Instead, this option controls whether the 441 they are credited and hence can initialize the RNG. Additionally, 442 other sources of randomness are always used, regardless of this 443 setting. Enabling this implies trusting that the CPU can supply high 444 quality and non-backdoored random numbers. 445 446 Say Y here unless you have reason to mistrust your CPU or believe 447 its RNG facilities may be faulty. This may also be configured at 448 boot time with "random.trust_cpu=on/off". 449 450config RANDOM_TRUST_BOOTLOADER 451 bool "Initialize RNG using bootloader-supplied seed" 452 default y 453 help 454 Initialize the RNG using a seed supplied by the bootloader or boot 455 environment (e.g. EFI or a bootloader-generated device tree). This 456 seed is not used directly, but is rather hashed into the main input 457 pool, and this happens regardless of whether or not this option is 458 enabled. Instead, this option controls whether the seed is credited 459 and hence can initialize the RNG. Additionally, other sources of 460 randomness are always used, regardless of this setting. Enabling 461 this implies trusting that the bootloader can supply high quality and 462 non-backdoored seeds. 463 464 Say Y here unless you have reason to mistrust your bootloader or 465 believe its RNG facilities may be faulty. This may also be configured 466 at boot time with "random.trust_bootloader=on/off". 467 468endmenu 469