1# SPDX-License-Identifier: GPL-2.0
2#
3# Character device configuration
4#
5
6menu "Character devices"
7
8source "drivers/tty/Kconfig"
9
10config DEVMEM
11	bool "/dev/mem virtual device support"
12	default y
13	help
14	  Say Y here if you want to support the /dev/mem device.
15	  The /dev/mem device is used to access areas of physical
16	  memory.
17	  When in doubt, say "Y".
18
19config DEVKMEM
20	bool "/dev/kmem virtual device support"
21	# On arm64, VMALLOC_START < PAGE_OFFSET, which confuses kmem read/write
22	depends on !ARM64
23	help
24	  Say Y here if you want to support the /dev/kmem device. The
25	  /dev/kmem device is rarely used, but can be used for certain
26	  kind of kernel debugging operations.
27	  When in doubt, say "N".
28
29config SGI_SNSC
30	bool "SGI Altix system controller communication support"
31	depends on (IA64_SGI_SN2 || IA64_GENERIC)
32	help
33	  If you have an SGI Altix and you want to enable system
34	  controller communication from user space (you want this!),
35	  say Y.  Otherwise, say N.
36
37config SGI_TIOCX
38       bool "SGI TIO CX driver support"
39       depends on (IA64_SGI_SN2 || IA64_GENERIC)
40       help
41         If you have an SGI Altix and you have fpga devices attached
42         to your TIO, say Y here, otherwise say N.
43
44config SGI_MBCS
45       tristate "SGI FPGA Core Services driver support"
46       depends on SGI_TIOCX
47       help
48         If you have an SGI Altix with an attached SABrick
49         say Y or M here, otherwise say N.
50
51source "drivers/tty/serial/Kconfig"
52source "drivers/tty/serdev/Kconfig"
53
54config TTY_PRINTK
55	tristate "TTY driver to output user messages via printk"
56	depends on EXPERT && TTY
57	default n
58	---help---
59	  If you say Y here, the support for writing user messages (i.e.
60	  console messages) via printk is available.
61
62	  The feature is useful to inline user messages with kernel
63	  messages.
64	  In order to use this feature, you should output user messages
65	  to /dev/ttyprintk or redirect console to this TTY.
66
67	  If unsure, say N.
68
69config PRINTER
70	tristate "Parallel printer support"
71	depends on PARPORT
72	---help---
73	  If you intend to attach a printer to the parallel port of your Linux
74	  box (as opposed to using a serial printer; if the connector at the
75	  printer has 9 or 25 holes ["female"], then it's serial), say Y.
76	  Also read the Printing-HOWTO, available from
77	  <http://www.tldp.org/docs.html#howto>.
78
79	  It is possible to share one parallel port among several devices
80	  (e.g. printer and ZIP drive) and it is safe to compile the
81	  corresponding drivers into the kernel.
82
83	  To compile this driver as a module, choose M here and read
84	  <file:Documentation/admin-guide/parport.rst>.  The module will be called lp.
85
86	  If you have several parallel ports, you can specify which ports to
87	  use with the "lp" kernel command line option.  (Try "man bootparam"
88	  or see the documentation of your boot loader (lilo or loadlin) about
89	  how to pass options to the kernel at boot time.)  The syntax of the
90	  "lp" command line option can be found in <file:drivers/char/lp.c>.
91
92	  If you have more than 8 printers, you need to increase the LP_NO
93	  macro in lp.c and the PARPORT_MAX macro in parport.h.
94
95config LP_CONSOLE
96	bool "Support for console on line printer"
97	depends on PRINTER
98	---help---
99	  If you want kernel messages to be printed out as they occur, you
100	  can have a console on the printer. This option adds support for
101	  doing that; to actually get it to happen you need to pass the
102	  option "console=lp0" to the kernel at boot time.
103
104	  If the printer is out of paper (or off, or unplugged, or too
105	  busy..) the kernel will stall until the printer is ready again.
106	  By defining CONSOLE_LP_STRICT to 0 (at your own risk) you
107	  can make the kernel continue when this happens,
108	  but it'll lose the kernel messages.
109
110	  If unsure, say N.
111
112config PPDEV
113	tristate "Support for user-space parallel port device drivers"
114	depends on PARPORT
115	---help---
116	  Saying Y to this adds support for /dev/parport device nodes.  This
117	  is needed for programs that want portable access to the parallel
118	  port, for instance deviceid (which displays Plug-and-Play device
119	  IDs).
120
121	  This is the parallel port equivalent of SCSI generic support (sg).
122	  It is safe to say N to this -- it is not needed for normal printing
123	  or parallel port CD-ROM/disk support.
124
125	  To compile this driver as a module, choose M here: the
126	  module will be called ppdev.
127
128	  If unsure, say N.
129
130source "drivers/tty/hvc/Kconfig"
131
132config VIRTIO_CONSOLE
133	tristate "Virtio console"
134	depends on VIRTIO && TTY
135	select HVC_DRIVER
136	help
137	  Virtio console for use with hypervisors.
138
139	  Also serves as a general-purpose serial device for data
140	  transfer between the guest and host.  Character devices at
141	  /dev/vportNpn will be created when corresponding ports are
142	  found, where N is the device number and n is the port number
143	  within that device.  If specified by the host, a sysfs
144	  attribute called 'name' will be populated with a name for
145	  the port which can be used by udev scripts to create a
146	  symlink to the device.
147
148config IBM_BSR
149	tristate "IBM POWER Barrier Synchronization Register support"
150	depends on PPC_PSERIES
151	help
152	  This devices exposes a hardware mechanism for fast synchronization
153	  of threads across a large system which avoids bouncing a cacheline
154	  between several cores on a system
155
156config POWERNV_OP_PANEL
157	tristate "IBM POWERNV Operator Panel Display support"
158	depends on PPC_POWERNV
159	default m
160	help
161	  If you say Y here, a special character device node, /dev/op_panel,
162	  will be created which exposes the operator panel display on IBM
163	  Power Systems machines with FSPs.
164
165	  If you don't require access to the operator panel display from user
166	  space, say N.
167
168	  If unsure, say M here to build it as a module called powernv-op-panel.
169
170source "drivers/char/ipmi/Kconfig"
171
172config DS1620
173	tristate "NetWinder thermometer support"
174	depends on ARCH_NETWINDER
175	help
176	  Say Y here to include support for the thermal management hardware
177	  found in the NetWinder. This driver allows the user to control the
178	  temperature set points and to read the current temperature.
179
180	  It is also possible to say M here to build it as a module (ds1620)
181	  It is recommended to be used on a NetWinder, but it is not a
182	  necessity.
183
184config NWBUTTON
185	tristate "NetWinder Button"
186	depends on ARCH_NETWINDER
187	---help---
188	  If you say Y here and create a character device node /dev/nwbutton
189	  with major and minor numbers 10 and 158 ("man mknod"), then every
190	  time the orange button is pressed a number of times, the number of
191	  times the button was pressed will be written to that device.
192
193	  This is most useful for applications, as yet unwritten, which
194	  perform actions based on how many times the button is pressed in a
195	  row.
196
197	  Do not hold the button down for too long, as the driver does not
198	  alter the behaviour of the hardware reset circuitry attached to the
199	  button; it will still execute a hard reset if the button is held
200	  down for longer than approximately five seconds.
201
202	  To compile this driver as a module, choose M here: the
203	  module will be called nwbutton.
204
205	  Most people will answer Y to this question and "Reboot Using Button"
206	  below to be able to initiate a system shutdown from the button.
207
208config NWBUTTON_REBOOT
209	bool "Reboot Using Button"
210	depends on NWBUTTON
211	help
212	  If you say Y here, then you will be able to initiate a system
213	  shutdown and reboot by pressing the orange button a number of times.
214	  The number of presses to initiate the shutdown is two by default,
215	  but this can be altered by modifying the value of NUM_PRESSES_REBOOT
216	  in nwbutton.h and recompiling the driver or, if you compile the
217	  driver as a module, you can specify the number of presses at load
218	  time with "insmod button reboot_count=<something>".
219
220config NWFLASH
221	tristate "NetWinder flash support"
222	depends on ARCH_NETWINDER
223	---help---
224	  If you say Y here and create a character device /dev/flash with
225	  major 10 and minor 160 you can manipulate the flash ROM containing
226	  the NetWinder firmware. Be careful as accidentally overwriting the
227	  flash contents can render your computer unbootable. On no account
228	  allow random users access to this device. :-)
229
230	  To compile this driver as a module, choose M here: the
231	  module will be called nwflash.
232
233	  If you're not sure, say N.
234
235source "drivers/char/hw_random/Kconfig"
236
237config NVRAM
238	tristate "/dev/nvram support"
239	depends on ATARI || X86 || GENERIC_NVRAM
240	---help---
241	  If you say Y here and create a character special file /dev/nvram
242	  with major number 10 and minor number 144 using mknod ("man mknod"),
243	  you get read and write access to the extra bytes of non-volatile
244	  memory in the real time clock (RTC), which is contained in every PC
245	  and most Ataris.  The actual number of bytes varies, depending on the
246	  nvram in the system, but is usually 114 (128-14 for the RTC).
247
248	  This memory is conventionally called "CMOS RAM" on PCs and "NVRAM"
249	  on Ataris. /dev/nvram may be used to view settings there, or to
250	  change them (with some utility). It could also be used to frequently
251	  save a few bits of very important data that may not be lost over
252	  power-off and for which writing to disk is too insecure. Note
253	  however that most NVRAM space in a PC belongs to the BIOS and you
254	  should NEVER idly tamper with it. See Ralf Brown's interrupt list
255	  for a guide to the use of CMOS bytes by your BIOS.
256
257	  On Atari machines, /dev/nvram is always configured and does not need
258	  to be selected.
259
260	  To compile this driver as a module, choose M here: the
261	  module will be called nvram.
262
263#
264# These legacy RTC drivers just cause too many conflicts with the generic
265# RTC framework ... let's not even try to coexist any more.
266#
267if RTC_LIB=n
268
269config RTC
270	tristate "Enhanced Real Time Clock Support (legacy PC RTC driver)"
271	depends on ALPHA || (MIPS && MACH_LOONGSON64)
272	---help---
273	  If you say Y here and create a character special file /dev/rtc with
274	  major number 10 and minor number 135 using mknod ("man mknod"), you
275	  will get access to the real time clock (or hardware clock) built
276	  into your computer.
277
278	  Every PC has such a clock built in. It can be used to generate
279	  signals from as low as 1Hz up to 8192Hz, and can also be used
280	  as a 24 hour alarm. It reports status information via the file
281	  /proc/driver/rtc and its behaviour is set by various ioctls on
282	  /dev/rtc.
283
284	  If you run Linux on a multiprocessor machine and said Y to
285	  "Symmetric Multi Processing" above, you should say Y here to read
286	  and set the RTC in an SMP compatible fashion.
287
288	  If you think you have a use for such a device (such as periodic data
289	  sampling), then say Y here, and read <file:Documentation/rtc.txt>
290	  for details.
291
292	  To compile this driver as a module, choose M here: the
293	  module will be called rtc.
294
295config JS_RTC
296	tristate "Enhanced Real Time Clock Support"
297	depends on SPARC32 && PCI
298	---help---
299	  If you say Y here and create a character special file /dev/rtc with
300	  major number 10 and minor number 135 using mknod ("man mknod"), you
301	  will get access to the real time clock (or hardware clock) built
302	  into your computer.
303
304	  Every PC has such a clock built in. It can be used to generate
305	  signals from as low as 1Hz up to 8192Hz, and can also be used
306	  as a 24 hour alarm. It reports status information via the file
307	  /proc/driver/rtc and its behaviour is set by various ioctls on
308	  /dev/rtc.
309
310	  If you think you have a use for such a device (such as periodic data
311	  sampling), then say Y here, and read <file:Documentation/rtc.txt>
312	  for details.
313
314	  To compile this driver as a module, choose M here: the
315	  module will be called js-rtc.
316
317config EFI_RTC
318	bool "EFI Real Time Clock Services"
319	depends on IA64
320
321endif # RTC_LIB
322
323config DTLK
324	tristate "Double Talk PC internal speech card support"
325	depends on ISA
326	help
327	  This driver is for the DoubleTalk PC, a speech synthesizer
328	  manufactured by RC Systems (<http://www.rcsys.com/>).  It is also
329	  called the `internal DoubleTalk'.
330
331	  To compile this driver as a module, choose M here: the
332	  module will be called dtlk.
333
334config XILINX_HWICAP
335	tristate "Xilinx HWICAP Support"
336	depends on XILINX_VIRTEX || MICROBLAZE
337	help
338	  This option enables support for Xilinx Internal Configuration
339	  Access Port (ICAP) driver.  The ICAP is used on Xilinx Virtex
340	  FPGA platforms to partially reconfigure the FPGA at runtime.
341
342	  If unsure, say N.
343
344config R3964
345	tristate "Siemens R3964 line discipline"
346	depends on TTY && BROKEN
347	---help---
348	  This driver allows synchronous communication with devices using the
349	  Siemens R3964 packet protocol. Unless you are dealing with special
350	  hardware like PLCs, you are unlikely to need this.
351
352	  To compile this driver as a module, choose M here: the
353	  module will be called n_r3964.
354
355	  If unsure, say N.
356
357config APPLICOM
358	tristate "Applicom intelligent fieldbus card support"
359	depends on PCI
360	---help---
361	  This driver provides the kernel-side support for the intelligent
362	  fieldbus cards made by Applicom International. More information
363	  about these cards can be found on the WWW at the address
364	  <http://www.applicom-int.com/>, or by email from David Woodhouse
365	  <dwmw2@infradead.org>.
366
367	  To compile this driver as a module, choose M here: the
368	  module will be called applicom.
369
370	  If unsure, say N.
371
372config SONYPI
373	tristate "Sony Vaio Programmable I/O Control Device support"
374	depends on X86_32 && PCI && INPUT
375	---help---
376	  This driver enables access to the Sony Programmable I/O Control
377	  Device which can be found in many (all ?) Sony Vaio laptops.
378
379	  If you have one of those laptops, read
380	  <file:Documentation/laptops/sonypi.txt>, and say Y or M here.
381
382	  To compile this driver as a module, choose M here: the
383	  module will be called sonypi.
384
385config GPIO_TB0219
386	tristate "TANBAC TB0219 GPIO support"
387	depends on TANBAC_TB022X
388	select GPIO_VR41XX
389
390source "drivers/char/pcmcia/Kconfig"
391
392config MWAVE
393	tristate "ACP Modem (Mwave) support"
394	depends on X86 && TTY
395	select SERIAL_8250
396	---help---
397	  The ACP modem (Mwave) for Linux is a WinModem. It is composed of a
398	  kernel driver and a user level application. Together these components
399	  support direct attachment to public switched telephone networks (PSTNs)
400	  and support selected world wide countries.
401
402	  This version of the ACP Modem driver supports the IBM Thinkpad 600E,
403	  600, and 770 that include on board ACP modem hardware.
404
405	  The modem also supports the standard communications port interface
406	  (ttySx) and is compatible with the Hayes AT Command Set.
407
408	  The user level application needed to use this driver can be found at
409	  the IBM Linux Technology Center (LTC) web site:
410	  <http://www.ibm.com/linux/ltc/>.
411
412	  If you own one of the above IBM Thinkpads which has the Mwave chipset
413	  in it, say Y.
414
415	  To compile this driver as a module, choose M here: the
416	  module will be called mwave.
417
418config SCx200_GPIO
419	tristate "NatSemi SCx200 GPIO Support"
420	depends on SCx200
421	select NSC_GPIO
422	help
423	  Give userspace access to the GPIO pins on the National
424	  Semiconductor SCx200 processors.
425
426	  If compiled as a module, it will be called scx200_gpio.
427
428config PC8736x_GPIO
429	tristate "NatSemi PC8736x GPIO Support"
430	depends on X86_32 && !UML
431	default SCx200_GPIO	# mostly N
432	select NSC_GPIO		# needed for support routines
433	help
434	  Give userspace access to the GPIO pins on the National
435	  Semiconductor PC-8736x (x=[03456]) SuperIO chip.  The chip
436	  has multiple functional units, inc several managed by
437	  hwmon/pc87360 driver.  Tested with PC-87366
438
439	  If compiled as a module, it will be called pc8736x_gpio.
440
441config NSC_GPIO
442	tristate "NatSemi Base GPIO Support"
443	depends on X86_32
444	# selected by SCx200_GPIO and PC8736x_GPIO
445	# what about 2 selectors differing: m != y
446	help
447	  Common support used (and needed) by scx200_gpio and
448	  pc8736x_gpio drivers.  If those drivers are built as
449	  modules, this one will be too, named nsc_gpio
450
451config RAW_DRIVER
452	tristate "RAW driver (/dev/raw/rawN)"
453	depends on BLOCK
454	help
455	  The raw driver permits block devices to be bound to /dev/raw/rawN.
456	  Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O.
457	  See the raw(8) manpage for more details.
458
459          Applications should preferably open the device (eg /dev/hda1)
460          with the O_DIRECT flag.
461
462config MAX_RAW_DEVS
463	int "Maximum number of RAW devices to support (1-65536)"
464	depends on RAW_DRIVER
465	range 1 65536
466	default "256"
467	help
468	  The maximum number of RAW devices that are supported.
469	  Default is 256. Increase this number in case you need lots of
470	  raw devices.
471
472config HPET
473	bool "HPET - High Precision Event Timer" if (X86 || IA64)
474	default n
475	depends on ACPI
476	help
477	  If you say Y here, you will have a miscdevice named "/dev/hpet/".  Each
478	  open selects one of the timers supported by the HPET.  The timers are
479	  non-periodic and/or periodic.
480
481config HPET_MMAP
482	bool "Allow mmap of HPET"
483	default y
484	depends on HPET
485	help
486	  If you say Y here, user applications will be able to mmap
487	  the HPET registers.
488
489config HPET_MMAP_DEFAULT
490	bool "Enable HPET MMAP access by default"
491	default y
492	depends on HPET_MMAP
493	help
494	  In some hardware implementations, the page containing HPET
495	  registers may also contain other things that shouldn't be
496	  exposed to the user.  This option selects the default (if
497	  kernel parameter hpet_mmap is not set) user access to the
498	  registers for applications that require it.
499
500config HANGCHECK_TIMER
501	tristate "Hangcheck timer"
502	depends on X86 || IA64 || PPC64 || S390
503	help
504	  The hangcheck-timer module detects when the system has gone
505	  out to lunch past a certain margin.  It can reboot the system
506	  or merely print a warning.
507
508config UV_MMTIMER
509	tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
510	depends on X86_UV
511	default m
512	help
513	  The uv_mmtimer device allows direct userspace access to the
514	  UV system timer.
515
516source "drivers/char/tpm/Kconfig"
517
518config TELCLOCK
519	tristate "Telecom clock driver for ATCA SBC"
520	depends on X86
521	default n
522	help
523	  The telecom clock device is specific to the MPCBL0010 and MPCBL0050
524	  ATCA computers and allows direct userspace access to the
525	  configuration of the telecom clock configuration settings.  This
526	  device is used for hardware synchronization across the ATCA backplane
527	  fabric.  Upon loading, the driver exports a sysfs directory,
528	  /sys/devices/platform/telco_clock, with a number of files for
529	  controlling the behavior of this hardware.
530
531config DEVPORT
532	bool "/dev/port character device"
533	depends on ISA || PCI
534	default y
535	help
536	  Say Y here if you want to support the /dev/port device. The /dev/port
537	  device is similar to /dev/mem, but for I/O ports.
538
539source "drivers/s390/char/Kconfig"
540
541source "drivers/char/xillybus/Kconfig"
542
543config ADI
544	tristate "SPARC Privileged ADI driver"
545	depends on SPARC64
546	default m
547	help
548	  SPARC M7 and newer processors utilize ADI (Application Data
549	  Integrity) to version and protect memory.  This driver provides
550	  read/write access to the ADI versions for privileged processes.
551	  This feature is also known as MCD (Memory Corruption Detection)
552	  and SSM (Silicon Secured Memory).  Intended consumers of this
553	  driver include crash and makedumpfile.
554
555config RANDOM_TRUST_CPU
556	bool "Initialize RNG using CPU RNG instructions"
557	default y
558	depends on ARCH_RANDOM
559	help
560	  Initialize the RNG using random numbers supplied by the CPU's
561	  RNG instructions (e.g. RDRAND), if supported and available. These
562	  random numbers are never used directly, but are rather hashed into
563	  the main input pool, and this happens regardless of whether or not
564	  this option is enabled. Instead, this option controls whether the
565	  they are credited and hence can initialize the RNG. Additionally,
566	  other sources of randomness are always used, regardless of this
567	  setting.  Enabling this implies trusting that the CPU can supply high
568	  quality and non-backdoored random numbers.
569
570	  Say Y here unless you have reason to mistrust your CPU or believe
571	  its RNG facilities may be faulty. This may also be configured at
572	  boot time with "random.trust_cpu=on/off".
573
574config RANDOM_TRUST_BOOTLOADER
575	bool "Initialize RNG using bootloader-supplied seed"
576	default y
577	help
578	  Initialize the RNG using a seed supplied by the bootloader or boot
579	  environment (e.g. EFI or a bootloader-generated device tree). This
580	  seed is not used directly, but is rather hashed into the main input
581	  pool, and this happens regardless of whether or not this option is
582	  enabled. Instead, this option controls whether the seed is credited
583	  and hence can initialize the RNG. Additionally, other sources of
584	  randomness are always used, regardless of this setting. Enabling
585	  this implies trusting that the bootloader can supply high quality and
586	  non-backdoored seeds.
587
588	  Say Y here unless you have reason to mistrust your bootloader or
589	  believe its RNG facilities may be faulty. This may also be configured
590	  at boot time with "random.trust_bootloader=on/off".
591
592endmenu
593