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.
22
23	  If unsure, say N.
24
25config 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
33config 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
59config 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
76config 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
94config 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
111config 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
119config 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
133source "drivers/char/ipmi/Kconfig"
134
135config 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
147config 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
171config 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
183config 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
198source "drivers/char/hw_random/Kconfig"
199
200config 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
211config 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
221config 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
236config 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
249config GPIO_TB0219
250	tristate "TANBAC TB0219 GPIO support"
251	depends on TANBAC_TB022X
252	select GPIO_VR41XX
253
254source "drivers/char/pcmcia/Kconfig"
255
256config 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
282config 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
292config 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
305config 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
315config 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
324config 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
347config 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
355config 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
364config 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
372config 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
383config 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
391config 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
399source "drivers/char/tpm/Kconfig"
400
401config 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
414source "drivers/s390/char/Kconfig"
415
416source "drivers/char/xillybus/Kconfig"
417
418config 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
430config 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
445config 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
454endmenu
455