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 depends on HAS_IOPORT || PARPORT_NOT_PC 38 help 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>. 44 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. 48 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. 51 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>. 57 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. 60 61config LP_CONSOLE 62 bool "Support for console on line printer" 63 depends on PRINTER 64 help 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. 69 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. 75 76 If unsure, say N. 77 78config PPDEV 79 tristate "Support for user-space parallel port device drivers" 80 depends on PARPORT 81 help 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 85 IDs). 86 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. 90 91 To compile this driver as a module, choose M here: the 92 module will be called ppdev. 93 94 If unsure, say N. 95 96config VIRTIO_CONSOLE 97 tristate "Virtio console" 98 depends on TTY 99 select HVC_DRIVER 100 select VIRTIO 101 help 102 Virtio console for use with hypervisors. 103 104 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. 112 113config IBM_BSR 114 tristate "IBM POWER Barrier Synchronization Register support" 115 depends on PPC_PSERIES 116 help 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 120 121config POWERNV_OP_PANEL 122 tristate "IBM POWERNV Operator Panel Display support" 123 depends on PPC_POWERNV 124 default m 125 help 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. 129 130 If you don't require access to the operator panel display from user 131 space, say N. 132 133 If unsure, say M here to build it as a module called powernv-op-panel. 134 135source "drivers/char/ipmi/Kconfig" 136 137config DS1620 138 tristate "NetWinder thermometer support" 139 depends on ARCH_NETWINDER 140 help 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. 144 145 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 147 necessity. 148 149config NWBUTTON 150 tristate "NetWinder Button" 151 depends on ARCH_NETWINDER 152 help 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. 157 158 This is most useful for applications, as yet unwritten, which 159 perform actions based on how many times the button is pressed in a 160 row. 161 162 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. 166 167 To compile this driver as a module, choose M here: the 168 module will be called nwbutton. 169 170 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. 172 173config NWBUTTON_REBOOT 174 bool "Reboot Using Button" 175 depends on NWBUTTON 176 help 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>". 184 185config NWFLASH 186 tristate "NetWinder flash support" 187 depends on ARCH_NETWINDER 188 help 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. :-) 194 195 To compile this driver as a module, choose M here: the 196 module will be called nwflash. 197 198 If you're not sure, say N. 199 200source "drivers/char/hw_random/Kconfig" 201 202config XILINX_HWICAP 203 tristate "Xilinx HWICAP Support" 204 depends on MICROBLAZE 205 help 206 This option enables support for Xilinx Internal Configuration 207 Access Port (ICAP) driver. The ICAP is used on Xilinx Virtex 208 FPGA platforms to partially reconfigure the FPGA at runtime. 209 210 If unsure, say N. 211 212config SONYPI 213 tristate "Sony Vaio Programmable I/O Control Device support" 214 depends on X86_32 && PCI && INPUT && HAS_IOPORT 215 depends on ACPI_EC || !ACPI 216 help 217 This driver enables access to the Sony Programmable I/O Control 218 Device which can be found in many (all ?) Sony Vaio laptops. 219 220 If you have one of those laptops, read 221 <file:Documentation/admin-guide/laptops/sonypi.rst>, and say Y or M here. 222 223 To compile this driver as a module, choose M here: the 224 module will be called sonypi. 225 226config SCx200_GPIO 227 tristate "NatSemi SCx200 GPIO Support" 228 depends on SCx200 229 select NSC_GPIO 230 help 231 Give userspace access to the GPIO pins on the National 232 Semiconductor SCx200 processors. 233 234 If compiled as a module, it will be called scx200_gpio. 235 236config PC8736x_GPIO 237 tristate "NatSemi PC8736x GPIO Support" 238 depends on X86_32 && !UML 239 default SCx200_GPIO # mostly N 240 select NSC_GPIO # needed for support routines 241 help 242 Give userspace access to the GPIO pins on the National 243 Semiconductor PC-8736x (x=[03456]) SuperIO chip. The chip 244 has multiple functional units, inc several managed by 245 hwmon/pc87360 driver. Tested with PC-87366 246 247 If compiled as a module, it will be called pc8736x_gpio. 248 249config NSC_GPIO 250 tristate "NatSemi Base GPIO Support" 251 depends on X86_32 252 # selected by SCx200_GPIO and PC8736x_GPIO 253 # what about 2 selectors differing: m != y 254 help 255 Common support used (and needed) by scx200_gpio and 256 pc8736x_gpio drivers. If those drivers are built as 257 modules, this one will be too, named nsc_gpio 258 259config DEVMEM 260 bool "/dev/mem virtual device support" 261 default y 262 help 263 Say Y here if you want to support the /dev/mem device. 264 The /dev/mem device is used to access areas of physical 265 memory. 266 When in doubt, say "Y". 267 268config NVRAM 269 tristate "/dev/nvram support" 270 depends on X86 || HAVE_ARCH_NVRAM_OPS 271 default M68K || PPC 272 help 273 If you say Y here and create a character special file /dev/nvram 274 with major number 10 and minor number 144 using mknod ("man mknod"), 275 you get read and write access to the non-volatile memory. 276 277 /dev/nvram may be used to view settings in NVRAM or to change them 278 (with some utility). It could also be used to frequently 279 save a few bits of very important data that may not be lost over 280 power-off and for which writing to disk is too insecure. Note 281 however that most NVRAM space in a PC belongs to the BIOS and you 282 should NEVER idly tamper with it. See Ralf Brown's interrupt list 283 for a guide to the use of CMOS bytes by your BIOS. 284 285 This memory is conventionally called "NVRAM" on PowerPC machines, 286 "CMOS RAM" on PCs, "NVRAM" on Ataris and "PRAM" on Macintoshes. 287 288 To compile this driver as a module, choose M here: the 289 module will be called nvram. 290 291config DEVPORT 292 bool "/dev/port character device" 293 depends on HAS_IOPORT 294 default y 295 help 296 Say Y here if you want to support the /dev/port device. The /dev/port 297 device is similar to /dev/mem, but for I/O ports. 298 299config HPET 300 bool "HPET - High Precision Event Timer" if X86 301 default n 302 depends on ACPI 303 help 304 If you say Y here, you will have a miscdevice named "/dev/hpet/". Each 305 open selects one of the timers supported by the HPET. The timers are 306 non-periodic and/or periodic. 307 308config HPET_MMAP 309 bool "Allow mmap of HPET" 310 default y 311 depends on HPET 312 help 313 If you say Y here, user applications will be able to mmap 314 the HPET registers. 315 316config HPET_MMAP_DEFAULT 317 bool "Enable HPET MMAP access by default" 318 default y 319 depends on HPET_MMAP 320 help 321 In some hardware implementations, the page containing HPET 322 registers may also contain other things that shouldn't be 323 exposed to the user. This option selects the default (if 324 kernel parameter hpet_mmap is not set) user access to the 325 registers for applications that require it. 326 327config HANGCHECK_TIMER 328 tristate "Hangcheck timer" 329 depends on X86 || PPC64 || S390 330 help 331 The hangcheck-timer module detects when the system has gone 332 out to lunch past a certain margin. It can reboot the system 333 or merely print a warning. 334 335config UV_MMTIMER 336 tristate "UV_MMTIMER Memory mapped RTC for SGI UV" 337 depends on X86_UV 338 default m 339 help 340 The uv_mmtimer device allows direct userspace access to the 341 UV system timer. 342 343source "drivers/char/tpm/Kconfig" 344 345config TELCLOCK 346 tristate "Telecom clock driver for ATCA SBC" 347 depends on X86 348 default n 349 help 350 The telecom clock device is specific to the MPCBL0010 and MPCBL0050 351 ATCA computers and allows direct userspace access to the 352 configuration of the telecom clock configuration settings. This 353 device is used for hardware synchronization across the ATCA backplane 354 fabric. Upon loading, the driver exports a sysfs directory, 355 /sys/devices/faux/telco_clock, with a number of files for 356 controlling the behavior of this hardware. 357 358source "drivers/s390/char/Kconfig" 359 360source "drivers/char/xillybus/Kconfig" 361 362config ADI 363 tristate "SPARC Privileged ADI driver" 364 depends on SPARC64 365 default m 366 help 367 SPARC M7 and newer processors utilize ADI (Application Data 368 Integrity) to version and protect memory. This driver provides 369 read/write access to the ADI versions for privileged processes. 370 This feature is also known as MCD (Memory Corruption Detection) 371 and SSM (Silicon Secured Memory). Intended consumers of this 372 driver include crash and makedumpfile. 373 374endmenu 375