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 455