drivers/char/Kconfig - kernel/msm-4.9 - Gitiles

 #
 # Character device configuration
 #

 menu "Character devices"

 source "drivers/tty/Kconfig"

 config DEVMEM
 	bool "/dev/mem virtual device support"
 	default y
 	help
 	  Say Y here if you want to support the /dev/mem device.
 	  The /dev/mem device is used to access areas of physical
 	  memory.
 	  When in doubt, say "Y".

 config DEVKMEM
 	bool "/dev/kmem virtual device support"
 	default y
 	help
 	  Say Y here if you want to support the /dev/kmem device. The
 	  /dev/kmem device is rarely used, but can be used for certain
 	  kind of kernel debugging operations.
 	  When in doubt, say "N".

 config SGI_SNSC
 	bool "SGI Altix system controller communication support"
 	depends on (IA64_SGI_SN2 || IA64_GENERIC)
 	help
 	  If you have an SGI Altix and you want to enable system
 	  controller communication from user space (you want this!),
 	  say Y.  Otherwise, say N.

 config SGI_TIOCX
        bool "SGI TIO CX driver support"
        depends on (IA64_SGI_SN2 || IA64_GENERIC)
        help
          If you have an SGI Altix and you have fpga devices attached
          to your TIO, say Y here, otherwise say N.

 config SGI_MBCS
        tristate "SGI FPGA Core Services driver support"
        depends on SGI_TIOCX
        help
          If you have an SGI Altix with an attached SABrick
          say Y or M here, otherwise say N.

 source "drivers/tty/serial/Kconfig"

 config TTY_PRINTK
 	tristate "TTY driver to output user messages via printk"
 	depends on EXPERT && TTY
 	default n
 	---help---
 	  If you say Y here, the support for writing user messages (i.e.
 	  console messages) via printk is available.

 	  The feature is useful to inline user messages with kernel
 	  messages.
 	  In order to use this feature, you should output user messages
 	  to /dev/ttyprintk or redirect console to this TTY.

 	  If unsure, say N.

 config BFIN_OTP
 	tristate "Blackfin On-Chip OTP Memory Support"
 	depends on BLACKFIN && (BF51x || BF52x || BF54x)
 	default y
 	help
 	  If you say Y here, you will get support for a character device
 	  interface into the One Time Programmable memory pages that are
 	  stored on the Blackfin processor.  This will not get you access
 	  to the secure memory pages however.  You will need to write your
 	  own secure code and reader for that.

 	  To compile this driver as a module, choose M here: the module
 	  will be called bfin-otp.

 	  If unsure, it is safe to say Y.

 config BFIN_OTP_WRITE_ENABLE
 	bool "Enable writing support of OTP pages"
 	depends on BFIN_OTP
 	default n
 	help
 	  If you say Y here, you will enable support for writing of the
 	  OTP pages.  This is dangerous by nature as you can only program
 	  the pages once, so only enable this option when you actually
 	  need it so as to not inadvertently clobber data.

 	  If unsure, say N.

 config PRINTER
 	tristate "Parallel printer support"
 	depends on PARPORT
 	---help---
 	  If you intend to attach a printer to the parallel port of your Linux
 	  box (as opposed to using a serial printer; if the connector at the
 	  printer has 9 or 25 holes ["female"], then it's serial), say Y.
 	  Also read the Printing-HOWTO, available from
 	  <http://www.tldp.org/docs.html#howto>.

 	  It is possible to share one parallel port among several devices
 	  (e.g. printer and ZIP drive) and it is safe to compile the
 	  corresponding drivers into the kernel.

 	  To compile this driver as a module, choose M here and read
 	  <file:Documentation/parport.txt>.  The module will be called lp.

 	  If you have several parallel ports, you can specify which ports to
 	  use with the "lp" kernel command line option.  (Try "man bootparam"
 	  or see the documentation of your boot loader (lilo or loadlin) about
 	  how to pass options to the kernel at boot time.)  The syntax of the
 	  "lp" command line option can be found in <file:drivers/char/lp.c>.

 	  If you have more than 8 printers, you need to increase the LP_NO
 	  macro in lp.c and the PARPORT_MAX macro in parport.h.

 config LP_CONSOLE
 	bool "Support for console on line printer"
 	depends on PRINTER
 	---help---
 	  If you want kernel messages to be printed out as they occur, you
 	  can have a console on the printer. This option adds support for
 	  doing that; to actually get it to happen you need to pass the
 	  option "console=lp0" to the kernel at boot time.

 	  If the printer is out of paper (or off, or unplugged, or too
 	  busy..) the kernel will stall until the printer is ready again.
 	  By defining CONSOLE_LP_STRICT to 0 (at your own risk) you
 	  can make the kernel continue when this happens,
 	  but it'll lose the kernel messages.

 	  If unsure, say N.

 config PPDEV
 	tristate "Support for user-space parallel port device drivers"
 	depends on PARPORT
 	---help---
 	  Saying Y to this adds support for /dev/parport device nodes.  This
 	  is needed for programs that want portable access to the parallel
 	  port, for instance deviceid (which displays Plug-and-Play device
 	  IDs).

 	  This is the parallel port equivalent of SCSI generic support (sg).
 	  It is safe to say N to this -- it is not needed for normal printing
 	  or parallel port CD-ROM/disk support.

 	  To compile this driver as a module, choose M here: the
 	  module will be called ppdev.

 	  If unsure, say N.

 source "drivers/tty/hvc/Kconfig"

 config VIRTIO_CONSOLE
 	tristate "Virtio console"
 	depends on VIRTIO && TTY
 	select HVC_DRIVER
 	help
 	  Virtio console for use with lguest and other hypervisors.

 	  Also serves as a general-purpose serial device for data
 	  transfer between the guest and host.  Character devices at
 	  /dev/vportNpn will be created when corresponding ports are
 	  found, where N is the device number and n is the port number
 	  within that device.  If specified by the host, a sysfs
 	  attribute called 'name' will be populated with a name for
 	  the port which can be used by udev scripts to create a
 	  symlink to the device.

 config IBM_BSR
 	tristate "IBM POWER Barrier Synchronization Register support"
 	depends on PPC_PSERIES
 	help
 	  This devices exposes a hardware mechanism for fast synchronization
 	  of threads across a large system which avoids bouncing a cacheline
 	  between several cores on a system

 config POWERNV_OP_PANEL
 	tristate "IBM POWERNV Operator Panel Display support"
 	depends on PPC_POWERNV
 	default m
 	help
 	  If you say Y here, a special character device node, /dev/op_panel,
 	  will be created which exposes the operator panel display on IBM
 	  Power Systems machines with FSPs.

 	  If you don't require access to the operator panel display from user
 	  space, say N.

 	  If unsure, say M here to build it as a module called powernv-op-panel.

 source "drivers/char/ipmi/Kconfig"

 config DS1620
 	tristate "NetWinder thermometer support"
 	depends on ARCH_NETWINDER
 	help
 	  Say Y here to include support for the thermal management hardware
 	  found in the NetWinder. This driver allows the user to control the
 	  temperature set points and to read the current temperature.

 	  It is also possible to say M here to build it as a module (ds1620)
 	  It is recommended to be used on a NetWinder, but it is not a
 	  necessity.

 config NWBUTTON
 	tristate "NetWinder Button"
 	depends on ARCH_NETWINDER
 	---help---
 	  If you say Y here and create a character device node /dev/nwbutton
 	  with major and minor numbers 10 and 158 ("man mknod"), then every
 	  time the orange button is pressed a number of times, the number of
 	  times the button was pressed will be written to that device.

 	  This is most useful for applications, as yet unwritten, which
 	  perform actions based on how many times the button is pressed in a
 	  row.

 	  Do not hold the button down for too long, as the driver does not
 	  alter the behaviour of the hardware reset circuitry attached to the
 	  button; it will still execute a hard reset if the button is held
 	  down for longer than approximately five seconds.

 	  To compile this driver as a module, choose M here: the
 	  module will be called nwbutton.

 	  Most people will answer Y to this question and "Reboot Using Button"
 	  below to be able to initiate a system shutdown from the button.

 config NWBUTTON_REBOOT
 	bool "Reboot Using Button"
 	depends on NWBUTTON
 	help
 	  If you say Y here, then you will be able to initiate a system
 	  shutdown and reboot by pressing the orange button a number of times.
 	  The number of presses to initiate the shutdown is two by default,
 	  but this can be altered by modifying the value of NUM_PRESSES_REBOOT
 	  in nwbutton.h and recompiling the driver or, if you compile the
 	  driver as a module, you can specify the number of presses at load
 	  time with "insmod button reboot_count=<something>".

 config NWFLASH
 	tristate "NetWinder flash support"
 	depends on ARCH_NETWINDER
 	---help---
 	  If you say Y here and create a character device /dev/flash with
 	  major 10 and minor 160 you can manipulate the flash ROM containing
 	  the NetWinder firmware. Be careful as accidentally overwriting the
 	  flash contents can render your computer unbootable. On no account
 	  allow random users access to this device. :-)

 	  To compile this driver as a module, choose M here: the
 	  module will be called nwflash.

 	  If you're not sure, say N.

 source "drivers/char/hw_random/Kconfig"

 config NVRAM
 	tristate "/dev/nvram support"
 	depends on ATARI || X86 || (ARM && RTC_DRV_CMOS) || GENERIC_NVRAM
 	---help---
 	  If you say Y here and create a character special file /dev/nvram
 	  with major number 10 and minor number 144 using mknod ("man mknod"),
 	  you get read and write access to the extra bytes of non-volatile
 	  memory in the real time clock (RTC), which is contained in every PC
 	  and most Ataris.  The actual number of bytes varies, depending on the
 	  nvram in the system, but is usually 114 (128-14 for the RTC).

 	  This memory is conventionally called "CMOS RAM" on PCs and "NVRAM"
 	  on Ataris. /dev/nvram may be used to view settings there, or to
 	  change them (with some utility). It could also be used to frequently
 	  save a few bits of very important data that may not be lost over
 	  power-off and for which writing to disk is too insecure. Note
 	  however that most NVRAM space in a PC belongs to the BIOS and you
 	  should NEVER idly tamper with it. See Ralf Brown's interrupt list
 	  for a guide to the use of CMOS bytes by your BIOS.

 	  On Atari machines, /dev/nvram is always configured and does not need
 	  to be selected.

 	  To compile this driver as a module, choose M here: the
 	  module will be called nvram.

 #
 # These legacy RTC drivers just cause too many conflicts with the generic
 # RTC framework ... let's not even try to coexist any more.
 #
 if RTC_LIB=n

 config RTC
 	tristate "Enhanced Real Time Clock Support (legacy PC RTC driver)"
 	depends on ALPHA || (MIPS && MACH_LOONGSON64) || MN10300
 	---help---
 	  If you say Y here and create a character special file /dev/rtc with
 	  major number 10 and minor number 135 using mknod ("man mknod"), you
 	  will get access to the real time clock (or hardware clock) built
 	  into your computer.

 	  Every PC has such a clock built in. It can be used to generate
 	  signals from as low as 1Hz up to 8192Hz, and can also be used
 	  as a 24 hour alarm. It reports status information via the file
 	  /proc/driver/rtc and its behaviour is set by various ioctls on
 	  /dev/rtc.

 	  If you run Linux on a multiprocessor machine and said Y to
 	  "Symmetric Multi Processing" above, you should say Y here to read
 	  and set the RTC in an SMP compatible fashion.

 	  If you think you have a use for such a device (such as periodic data
 	  sampling), then say Y here, and read <file:Documentation/rtc.txt>
 	  for details.

 	  To compile this driver as a module, choose M here: the
 	  module will be called rtc.

 config JS_RTC
 	tristate "Enhanced Real Time Clock Support"
 	depends on SPARC32 && PCI
 	---help---
 	  If you say Y here and create a character special file /dev/rtc with
 	  major number 10 and minor number 135 using mknod ("man mknod"), you
 	  will get access to the real time clock (or hardware clock) built
 	  into your computer.

 	  Every PC has such a clock built in. It can be used to generate
 	  signals from as low as 1Hz up to 8192Hz, and can also be used
 	  as a 24 hour alarm. It reports status information via the file
 	  /proc/driver/rtc and its behaviour is set by various ioctls on
 	  /dev/rtc.

 	  If you think you have a use for such a device (such as periodic data
 	  sampling), then say Y here, and read <file:Documentation/rtc.txt>
 	  for details.

 	  To compile this driver as a module, choose M here: the
 	  module will be called js-rtc.

 config GEN_RTC
 	tristate "Generic /dev/rtc emulation"
 	depends on RTC!=y
 	depends on ALPHA || M68K || MN10300 || PARISC || PPC || X86
 	---help---
 	  If you say Y here and create a character special file /dev/rtc with
 	  major number 10 and minor number 135 using mknod ("man mknod"), you
 	  will get access to the real time clock (or hardware clock) built
 	  into your computer.

 	  It reports status information via the file /proc/driver/rtc and its
 	  behaviour is set by various ioctls on /dev/rtc. If you enable the
 	  "extended RTC operation" below it will also provide an emulation
 	  for RTC_UIE which is required by some programs and may improve
 	  precision in some cases.

 	  To compile this driver as a module, choose M here: the
 	  module will be called genrtc.

 config GEN_RTC_X
 	bool "Extended RTC operation"
 	depends on GEN_RTC
 	help
 	  Provides an emulation for RTC_UIE which is required by some programs
 	  and may improve precision of the generic RTC support in some cases.

 config EFI_RTC
 	bool "EFI Real Time Clock Services"
 	depends on IA64

 config DS1302
 	tristate "DS1302 RTC support"
 	depends on M32R && (PLAT_M32700UT || PLAT_OPSPUT)
 	help
 	  If you say Y here and create a character special file /dev/rtc with
 	  major number 121 and minor number 0 using mknod ("man mknod"), you
 	  will get access to the real time clock (or hardware clock) built
 	  into your computer.

 endif # RTC_LIB

 config DTLK
 	tristate "Double Talk PC internal speech card support"
 	depends on ISA
 	help
 	  This driver is for the DoubleTalk PC, a speech synthesizer
 	  manufactured by RC Systems (<http://www.rcsys.com/>).  It is also
 	  called the `internal DoubleTalk'.

 	  To compile this driver as a module, choose M here: the
 	  module will be called dtlk.

 config XILINX_HWICAP
 	tristate "Xilinx HWICAP Support"
 	depends on XILINX_VIRTEX || MICROBLAZE
 	help
 	  This option enables support for Xilinx Internal Configuration
 	  Access Port (ICAP) driver.  The ICAP is used on Xilinx Virtex
 	  FPGA platforms to partially reconfigure the FPGA at runtime.

 	  If unsure, say N.

 config R3964
 	tristate "Siemens R3964 line discipline"
 	depends on TTY
 	---help---
 	  This driver allows synchronous communication with devices using the
 	  Siemens R3964 packet protocol. Unless you are dealing with special
 	  hardware like PLCs, you are unlikely to need this.

 	  To compile this driver as a module, choose M here: the
 	  module will be called n_r3964.

 	  If unsure, say N.

 config APPLICOM
 	tristate "Applicom intelligent fieldbus card support"
 	depends on PCI
 	---help---
 	  This driver provides the kernel-side support for the intelligent
 	  fieldbus cards made by Applicom International. More information
 	  about these cards can be found on the WWW at the address
 	  <http://www.applicom-int.com/>, or by email from David Woodhouse
 	  <dwmw2@infradead.org>.

 	  To compile this driver as a module, choose M here: the
 	  module will be called applicom.

 	  If unsure, say N.

 config SONYPI
 	tristate "Sony Vaio Programmable I/O Control Device support"
 	depends on X86_32 && PCI && INPUT
 	---help---
 	  This driver enables access to the Sony Programmable I/O Control
 	  Device which can be found in many (all ?) Sony Vaio laptops.

 	  If you have one of those laptops, read
 	  <file:Documentation/laptops/sonypi.txt>, and say Y or M here.

 	  To compile this driver as a module, choose M here: the
 	  module will be called sonypi.

 config GPIO_TB0219
 	tristate "TANBAC TB0219 GPIO support"
 	depends on TANBAC_TB022X
 	select GPIO_VR41XX

 source "drivers/char/pcmcia/Kconfig"

 config MWAVE
 	tristate "ACP Modem (Mwave) support"
 	depends on X86 && TTY
 	select SERIAL_8250
 	---help---
 	  The ACP modem (Mwave) for Linux is a WinModem. It is composed of a
 	  kernel driver and a user level application. Together these components
 	  support direct attachment to public switched telephone networks (PSTNs)
 	  and support selected world wide countries.

 	  This version of the ACP Modem driver supports the IBM Thinkpad 600E,
 	  600, and 770 that include on board ACP modem hardware.

 	  The modem also supports the standard communications port interface
 	  (ttySx) and is compatible with the Hayes AT Command Set.

 	  The user level application needed to use this driver can be found at
 	  the IBM Linux Technology Center (LTC) web site:
 	  <http://www.ibm.com/linux/ltc/>.

 	  If you own one of the above IBM Thinkpads which has the Mwave chipset
 	  in it, say Y.

 	  To compile this driver as a module, choose M here: the
 	  module will be called mwave.

 config SCx200_GPIO
 	tristate "NatSemi SCx200 GPIO Support"
 	depends on SCx200
 	select NSC_GPIO
 	help
 	  Give userspace access to the GPIO pins on the National
 	  Semiconductor SCx200 processors.

 	  If compiled as a module, it will be called scx200_gpio.

 config PC8736x_GPIO
 	tristate "NatSemi PC8736x GPIO Support"
 	depends on X86_32 && !UML
 	default SCx200_GPIO	# mostly N
 	select NSC_GPIO		# needed for support routines
 	help
 	  Give userspace access to the GPIO pins on the National
 	  Semiconductor PC-8736x (x=[03456]) SuperIO chip.  The chip
 	  has multiple functional units, inc several managed by
 	  hwmon/pc87360 driver.  Tested with PC-87366

 	  If compiled as a module, it will be called pc8736x_gpio.

 config NSC_GPIO
 	tristate "NatSemi Base GPIO Support"
 	depends on X86_32
 	# selected by SCx200_GPIO and PC8736x_GPIO
 	# what about 2 selectors differing: m != y
 	help
 	  Common support used (and needed) by scx200_gpio and
 	  pc8736x_gpio drivers.  If those drivers are built as
 	  modules, this one will be too, named nsc_gpio

 config RAW_DRIVER
 	tristate "RAW driver (/dev/raw/rawN)"
 	depends on BLOCK
 	help
 	  The raw driver permits block devices to be bound to /dev/raw/rawN.
 	  Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O.
 	  See the raw(8) manpage for more details.

           Applications should preferably open the device (eg /dev/hda1)
           with the O_DIRECT flag.

 config MAX_RAW_DEVS
 	int "Maximum number of RAW devices to support (1-65536)"
 	depends on RAW_DRIVER
 	range 1 65536
 	default "256"
 	help
 	  The maximum number of RAW devices that are supported.
 	  Default is 256. Increase this number in case you need lots of
 	  raw devices.

 config HPET
 	bool "HPET - High Precision Event Timer" if (X86 || IA64)
 	default n
 	depends on ACPI
 	help
 	  If you say Y here, you will have a miscdevice named "/dev/hpet/".  Each
 	  open selects one of the timers supported by the HPET.  The timers are
 	  non-periodic and/or periodic.

 config HPET_MMAP
 	bool "Allow mmap of HPET"
 	default y
 	depends on HPET
 	help
 	  If you say Y here, user applications will be able to mmap
 	  the HPET registers.

 config HPET_MMAP_DEFAULT
 	bool "Enable HPET MMAP access by default"
 	default y
 	depends on HPET_MMAP
 	help
 	  In some hardware implementations, the page containing HPET
 	  registers may also contain other things that shouldn't be
 	  exposed to the user.  This option selects the default (if
 	  kernel parameter hpet_mmap is not set) user access to the
 	  registers for applications that require it.

 config HANGCHECK_TIMER
 	tristate "Hangcheck timer"
 	depends on X86 || IA64 || PPC64 || S390
 	help
 	  The hangcheck-timer module detects when the system has gone
 	  out to lunch past a certain margin.  It can reboot the system
 	  or merely print a warning.

 config MMTIMER
 	tristate "MMTIMER Memory mapped RTC for SGI Altix"
 	depends on IA64_GENERIC || IA64_SGI_SN2
 	default y
 	help
 	  The mmtimer device allows direct userspace access to the
 	  Altix system timer.

 config UV_MMTIMER
 	tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
 	depends on X86_UV
 	default m
 	help
 	  The uv_mmtimer device allows direct userspace access to the
 	  UV system timer.

 source "drivers/char/tpm/Kconfig"

 config TELCLOCK
 	tristate "Telecom clock driver for ATCA SBC"
 	depends on X86
 	default n
 	help
 	  The telecom clock device is specific to the MPCBL0010 and MPCBL0050
 	  ATCA computers and allows direct userspace access to the
 	  configuration of the telecom clock configuration settings.  This
 	  device is used for hardware synchronization across the ATCA backplane
 	  fabric.  Upon loading, the driver exports a sysfs directory,
 	  /sys/devices/platform/telco_clock, with a number of files for
 	  controlling the behavior of this hardware.

 config DEVPORT
 	bool
 	depends on ISA || PCI
 	default y

 source "drivers/s390/char/Kconfig"

 config TILE_SROM
 	bool "Character-device access via hypervisor to the Tilera SPI ROM"
 	depends on TILE
 	default y
 	---help---
 	  This device provides character-level read-write access
 	  to the SROM, typically via the "0", "1", and "2" devices
 	  in /dev/srom/.  The Tilera hypervisor makes the flash
 	  device appear much like a simple EEPROM, and knows
 	  how to partition a single ROM for multiple purposes.

 source "drivers/char/xillybus/Kconfig"

 endmenu
	#
	# Character device configuration
	#

	menu "Character devices"

	source "drivers/tty/Kconfig"

	config DEVMEM
	bool "/dev/mem virtual device support"
	default y
	help
	Say Y here if you want to support the /dev/mem device.
	The /dev/mem device is used to access areas of physical
	memory.
	When in doubt, say "Y".

	config DEVKMEM
	bool "/dev/kmem virtual device support"
	default y
	help
	Say Y here if you want to support the /dev/kmem device. The
	/dev/kmem device is rarely used, but can be used for certain
	kind of kernel debugging operations.
	When in doubt, say "N".

	config SGI_SNSC
	bool "SGI Altix system controller communication support"
	depends on (IA64_SGI_SN2 \|\| IA64_GENERIC)
	help
	If you have an SGI Altix and you want to enable system
	controller communication from user space (you want this!),
	say Y. Otherwise, say N.

	config SGI_TIOCX
	bool "SGI TIO CX driver support"
	depends on (IA64_SGI_SN2 \|\| IA64_GENERIC)
	help
	If you have an SGI Altix and you have fpga devices attached
	to your TIO, say Y here, otherwise say N.

	config SGI_MBCS
	tristate "SGI FPGA Core Services driver support"
	depends on SGI_TIOCX
	help
	If you have an SGI Altix with an attached SABrick
	say Y or M here, otherwise say N.

	source "drivers/tty/serial/Kconfig"

	config TTY_PRINTK
	tristate "TTY driver to output user messages via printk"
	depends on EXPERT && TTY
	default n
	---help---
	If you say Y here, the support for writing user messages (i.e.
	console messages) via printk is available.

	The feature is useful to inline user messages with kernel
	messages.
	In order to use this feature, you should output user messages
	to /dev/ttyprintk or redirect console to this TTY.

	If unsure, say N.

	config BFIN_OTP
	tristate "Blackfin On-Chip OTP Memory Support"
	depends on BLACKFIN && (BF51x \|\| BF52x \|\| BF54x)
	default y
	help
	If you say Y here, you will get support for a character device
	interface into the One Time Programmable memory pages that are
	stored on the Blackfin processor. This will not get you access
	to the secure memory pages however. You will need to write your
	own secure code and reader for that.

	To compile this driver as a module, choose M here: the module
	will be called bfin-otp.

	If unsure, it is safe to say Y.

	config BFIN_OTP_WRITE_ENABLE
	bool "Enable writing support of OTP pages"
	depends on BFIN_OTP
	default n
	help
	If you say Y here, you will enable support for writing of the
	OTP pages. This is dangerous by nature as you can only program
	the pages once, so only enable this option when you actually
	need it so as to not inadvertently clobber data.

	If unsure, say N.

	config PRINTER
	tristate "Parallel printer support"
	depends on PARPORT
	---help---
	If you intend to attach a printer to the parallel port of your Linux
	box (as opposed to using a serial printer; if the connector at the
	printer has 9 or 25 holes ["female"], then it's serial), say Y.
	Also read the Printing-HOWTO, available from
	<http://www.tldp.org/docs.html#howto>.

	It is possible to share one parallel port among several devices
	(e.g. printer and ZIP drive) and it is safe to compile the
	corresponding drivers into the kernel.

	To compile this driver as a module, choose M here and read
	<file:Documentation/parport.txt>. The module will be called lp.

	If you have several parallel ports, you can specify which ports to
	use with the "lp" kernel command line option. (Try "man bootparam"
	or see the documentation of your boot loader (lilo or loadlin) about
	how to pass options to the kernel at boot time.) The syntax of the
	"lp" command line option can be found in <file:drivers/char/lp.c>.

	If you have more than 8 printers, you need to increase the LP_NO
	macro in lp.c and the PARPORT_MAX macro in parport.h.

	config LP_CONSOLE
	bool "Support for console on line printer"
	depends on PRINTER
	---help---
	If you want kernel messages to be printed out as they occur, you
	can have a console on the printer. This option adds support for
	doing that; to actually get it to happen you need to pass the
	option "console=lp0" to the kernel at boot time.

	If the printer is out of paper (or off, or unplugged, or too
	busy..) the kernel will stall until the printer is ready again.
	By defining CONSOLE_LP_STRICT to 0 (at your own risk) you
	can make the kernel continue when this happens,
	but it'll lose the kernel messages.

	If unsure, say N.

	config PPDEV
	tristate "Support for user-space parallel port device drivers"
	depends on PARPORT
	---help---
	Saying Y to this adds support for /dev/parport device nodes. This
	is needed for programs that want portable access to the parallel
	port, for instance deviceid (which displays Plug-and-Play device
	IDs).

	This is the parallel port equivalent of SCSI generic support (sg).
	It is safe to say N to this -- it is not needed for normal printing
	or parallel port CD-ROM/disk support.

	To compile this driver as a module, choose M here: the
	module will be called ppdev.

	If unsure, say N.

	source "drivers/tty/hvc/Kconfig"

	config VIRTIO_CONSOLE
	tristate "Virtio console"
	depends on VIRTIO && TTY
	select HVC_DRIVER
	help
	Virtio console for use with lguest and other hypervisors.

	Also serves as a general-purpose serial device for data
	transfer between the guest and host. Character devices at
	/dev/vportNpn will be created when corresponding ports are
	found, where N is the device number and n is the port number
	within that device. If specified by the host, a sysfs
	attribute called 'name' will be populated with a name for
	the port which can be used by udev scripts to create a
	symlink to the device.

	config IBM_BSR
	tristate "IBM POWER Barrier Synchronization Register support"
	depends on PPC_PSERIES
	help
	This devices exposes a hardware mechanism for fast synchronization
	of threads across a large system which avoids bouncing a cacheline
	between several cores on a system

	config POWERNV_OP_PANEL
	tristate "IBM POWERNV Operator Panel Display support"
	depends on PPC_POWERNV
	default m
	help
	If you say Y here, a special character device node, /dev/op_panel,
	will be created which exposes the operator panel display on IBM
	Power Systems machines with FSPs.

	If you don't require access to the operator panel display from user
	space, say N.

	If unsure, say M here to build it as a module called powernv-op-panel.

	source "drivers/char/ipmi/Kconfig"

	config DS1620
	tristate "NetWinder thermometer support"
	depends on ARCH_NETWINDER
	help
	Say Y here to include support for the thermal management hardware
	found in the NetWinder. This driver allows the user to control the
	temperature set points and to read the current temperature.

	It is also possible to say M here to build it as a module (ds1620)
	It is recommended to be used on a NetWinder, but it is not a
	necessity.

	config NWBUTTON
	tristate "NetWinder Button"
	depends on ARCH_NETWINDER
	---help---
	If you say Y here and create a character device node /dev/nwbutton
	with major and minor numbers 10 and 158 ("man mknod"), then every
	time the orange button is pressed a number of times, the number of
	times the button was pressed will be written to that device.

	This is most useful for applications, as yet unwritten, which
	perform actions based on how many times the button is pressed in a
	row.

	Do not hold the button down for too long, as the driver does not
	alter the behaviour of the hardware reset circuitry attached to the
	button; it will still execute a hard reset if the button is held
	down for longer than approximately five seconds.

	To compile this driver as a module, choose M here: the
	module will be called nwbutton.

	Most people will answer Y to this question and "Reboot Using Button"
	below to be able to initiate a system shutdown from the button.

	config NWBUTTON_REBOOT
	bool "Reboot Using Button"
	depends on NWBUTTON
	help
	If you say Y here, then you will be able to initiate a system
	shutdown and reboot by pressing the orange button a number of times.
	The number of presses to initiate the shutdown is two by default,
	but this can be altered by modifying the value of NUM_PRESSES_REBOOT
	in nwbutton.h and recompiling the driver or, if you compile the
	driver as a module, you can specify the number of presses at load
	time with "insmod button reboot_count=<something>".

	config NWFLASH
	tristate "NetWinder flash support"
	depends on ARCH_NETWINDER
	---help---
	If you say Y here and create a character device /dev/flash with
	major 10 and minor 160 you can manipulate the flash ROM containing
	the NetWinder firmware. Be careful as accidentally overwriting the
	flash contents can render your computer unbootable. On no account
	allow random users access to this device. :-)

	To compile this driver as a module, choose M here: the
	module will be called nwflash.

	If you're not sure, say N.

	source "drivers/char/hw_random/Kconfig"

	config NVRAM
	tristate "/dev/nvram support"
	depends on ATARI \|\| X86 \|\| (ARM && RTC_DRV_CMOS) \|\| GENERIC_NVRAM
	---help---
	If you say Y here and create a character special file /dev/nvram
	with major number 10 and minor number 144 using mknod ("man mknod"),
	you get read and write access to the extra bytes of non-volatile
	memory in the real time clock (RTC), which is contained in every PC
	and most Ataris. The actual number of bytes varies, depending on the
	nvram in the system, but is usually 114 (128-14 for the RTC).

	This memory is conventionally called "CMOS RAM" on PCs and "NVRAM"
	on Ataris. /dev/nvram may be used to view settings there, or to
	change them (with some utility). It could also be used to frequently
	save a few bits of very important data that may not be lost over
	power-off and for which writing to disk is too insecure. Note
	however that most NVRAM space in a PC belongs to the BIOS and you
	should NEVER idly tamper with it. See Ralf Brown's interrupt list
	for a guide to the use of CMOS bytes by your BIOS.

	On Atari machines, /dev/nvram is always configured and does not need
	to be selected.

	To compile this driver as a module, choose M here: the
	module will be called nvram.

	#
	# These legacy RTC drivers just cause too many conflicts with the generic
	# RTC framework ... let's not even try to coexist any more.
	#
	if RTC_LIB=n

	config RTC
	tristate "Enhanced Real Time Clock Support (legacy PC RTC driver)"
	depends on ALPHA \|\| (MIPS && MACH_LOONGSON64) \|\| MN10300
	---help---
	If you say Y here and create a character special file /dev/rtc with
	major number 10 and minor number 135 using mknod ("man mknod"), you
	will get access to the real time clock (or hardware clock) built
	into your computer.

	Every PC has such a clock built in. It can be used to generate
	signals from as low as 1Hz up to 8192Hz, and can also be used
	as a 24 hour alarm. It reports status information via the file
	/proc/driver/rtc and its behaviour is set by various ioctls on
	/dev/rtc.

	If you run Linux on a multiprocessor machine and said Y to
	"Symmetric Multi Processing" above, you should say Y here to read
	and set the RTC in an SMP compatible fashion.

	If you think you have a use for such a device (such as periodic data
	sampling), then say Y here, and read <file:Documentation/rtc.txt>
	for details.

	To compile this driver as a module, choose M here: the
	module will be called rtc.

	config JS_RTC
	tristate "Enhanced Real Time Clock Support"
	depends on SPARC32 && PCI
	---help---
	If you say Y here and create a character special file /dev/rtc with
	major number 10 and minor number 135 using mknod ("man mknod"), you
	will get access to the real time clock (or hardware clock) built
	into your computer.

	Every PC has such a clock built in. It can be used to generate
	signals from as low as 1Hz up to 8192Hz, and can also be used
	as a 24 hour alarm. It reports status information via the file
	/proc/driver/rtc and its behaviour is set by various ioctls on
	/dev/rtc.

	If you think you have a use for such a device (such as periodic data
	sampling), then say Y here, and read <file:Documentation/rtc.txt>
	for details.

	To compile this driver as a module, choose M here: the
	module will be called js-rtc.

	config GEN_RTC
	tristate "Generic /dev/rtc emulation"
	depends on RTC!=y
	depends on ALPHA \|\| M68K \|\| MN10300 \|\| PARISC \|\| PPC \|\| X86
	---help---
	If you say Y here and create a character special file /dev/rtc with
	major number 10 and minor number 135 using mknod ("man mknod"), you
	will get access to the real time clock (or hardware clock) built
	into your computer.

	It reports status information via the file /proc/driver/rtc and its
	behaviour is set by various ioctls on /dev/rtc. If you enable the
	"extended RTC operation" below it will also provide an emulation
	for RTC_UIE which is required by some programs and may improve
	precision in some cases.

	To compile this driver as a module, choose M here: the
	module will be called genrtc.

	config GEN_RTC_X
	bool "Extended RTC operation"
	depends on GEN_RTC
	help
	Provides an emulation for RTC_UIE which is required by some programs
	and may improve precision of the generic RTC support in some cases.

	config EFI_RTC
	bool "EFI Real Time Clock Services"
	depends on IA64

	config DS1302
	tristate "DS1302 RTC support"
	depends on M32R && (PLAT_M32700UT \|\| PLAT_OPSPUT)
	help
	If you say Y here and create a character special file /dev/rtc with
	major number 121 and minor number 0 using mknod ("man mknod"), you
	will get access to the real time clock (or hardware clock) built
	into your computer.

	endif # RTC_LIB

	config DTLK
	tristate "Double Talk PC internal speech card support"
	depends on ISA
	help
	This driver is for the DoubleTalk PC, a speech synthesizer
	manufactured by RC Systems (<http://www.rcsys.com/>). It is also
	called the `internal DoubleTalk'.

	To compile this driver as a module, choose M here: the
	module will be called dtlk.

	config XILINX_HWICAP
	tristate "Xilinx HWICAP Support"
	depends on XILINX_VIRTEX \|\| MICROBLAZE
	help
	This option enables support for Xilinx Internal Configuration
	Access Port (ICAP) driver. The ICAP is used on Xilinx Virtex
	FPGA platforms to partially reconfigure the FPGA at runtime.

	If unsure, say N.

	config R3964
	tristate "Siemens R3964 line discipline"
	depends on TTY
	---help---
	This driver allows synchronous communication with devices using the
	Siemens R3964 packet protocol. Unless you are dealing with special
	hardware like PLCs, you are unlikely to need this.

	To compile this driver as a module, choose M here: the
	module will be called n_r3964.

	If unsure, say N.

	config APPLICOM
	tristate "Applicom intelligent fieldbus card support"
	depends on PCI
	---help---
	This driver provides the kernel-side support for the intelligent
	fieldbus cards made by Applicom International. More information
	about these cards can be found on the WWW at the address
	<http://www.applicom-int.com/>, or by email from David Woodhouse
	<dwmw2@infradead.org>.

	To compile this driver as a module, choose M here: the
	module will be called applicom.

	If unsure, say N.

	config SONYPI
	tristate "Sony Vaio Programmable I/O Control Device support"
	depends on X86_32 && PCI && INPUT
	---help---
	This driver enables access to the Sony Programmable I/O Control
	Device which can be found in many (all ?) Sony Vaio laptops.

	If you have one of those laptops, read
	<file:Documentation/laptops/sonypi.txt>, and say Y or M here.

	To compile this driver as a module, choose M here: the
	module will be called sonypi.

	config GPIO_TB0219
	tristate "TANBAC TB0219 GPIO support"
	depends on TANBAC_TB022X
	select GPIO_VR41XX

	source "drivers/char/pcmcia/Kconfig"

	config MWAVE
	tristate "ACP Modem (Mwave) support"
	depends on X86 && TTY
	select SERIAL_8250
	---help---
	The ACP modem (Mwave) for Linux is a WinModem. It is composed of a
	kernel driver and a user level application. Together these components
	support direct attachment to public switched telephone networks (PSTNs)
	and support selected world wide countries.

	This version of the ACP Modem driver supports the IBM Thinkpad 600E,
	600, and 770 that include on board ACP modem hardware.

	The modem also supports the standard communications port interface
	(ttySx) and is compatible with the Hayes AT Command Set.

	The user level application needed to use this driver can be found at
	the IBM Linux Technology Center (LTC) web site:
	<http://www.ibm.com/linux/ltc/>.

	If you own one of the above IBM Thinkpads which has the Mwave chipset
	in it, say Y.

	To compile this driver as a module, choose M here: the
	module will be called mwave.

	config SCx200_GPIO
	tristate "NatSemi SCx200 GPIO Support"
	depends on SCx200
	select NSC_GPIO
	help
	Give userspace access to the GPIO pins on the National
	Semiconductor SCx200 processors.

	If compiled as a module, it will be called scx200_gpio.

	config PC8736x_GPIO
	tristate "NatSemi PC8736x GPIO Support"
	depends on X86_32 && !UML
	default SCx200_GPIO # mostly N
	select NSC_GPIO # needed for support routines
	help
	Give userspace access to the GPIO pins on the National
	Semiconductor PC-8736x (x=[03456]) SuperIO chip. The chip
	has multiple functional units, inc several managed by
	hwmon/pc87360 driver. Tested with PC-87366

	If compiled as a module, it will be called pc8736x_gpio.

	config NSC_GPIO
	tristate "NatSemi Base GPIO Support"
	depends on X86_32
	# selected by SCx200_GPIO and PC8736x_GPIO
	# what about 2 selectors differing: m != y
	help
	Common support used (and needed) by scx200_gpio and
	pc8736x_gpio drivers. If those drivers are built as
	modules, this one will be too, named nsc_gpio

	config RAW_DRIVER
	tristate "RAW driver (/dev/raw/rawN)"
	depends on BLOCK
	help
	The raw driver permits block devices to be bound to /dev/raw/rawN.
	Once bound, I/O against /dev/raw/rawN uses efficient zero-copy I/O.
	See the raw(8) manpage for more details.

	Applications should preferably open the device (eg /dev/hda1)
	with the O_DIRECT flag.

	config MAX_RAW_DEVS
	int "Maximum number of RAW devices to support (1-65536)"
	depends on RAW_DRIVER
	range 1 65536
	default "256"
	help
	The maximum number of RAW devices that are supported.
	Default is 256. Increase this number in case you need lots of
	raw devices.

	config HPET
	bool "HPET - High Precision Event Timer" if (X86 \|\| IA64)
	default n
	depends on ACPI
	help
	If you say Y here, you will have a miscdevice named "/dev/hpet/". Each
	open selects one of the timers supported by the HPET. The timers are
	non-periodic and/or periodic.

	config HPET_MMAP
	bool "Allow mmap of HPET"
	default y
	depends on HPET
	help
	If you say Y here, user applications will be able to mmap
	the HPET registers.

	config HPET_MMAP_DEFAULT
	bool "Enable HPET MMAP access by default"
	default y
	depends on HPET_MMAP
	help
	In some hardware implementations, the page containing HPET
	registers may also contain other things that shouldn't be
	exposed to the user. This option selects the default (if
	kernel parameter hpet_mmap is not set) user access to the
	registers for applications that require it.

	config HANGCHECK_TIMER
	tristate "Hangcheck timer"
	depends on X86 \|\| IA64 \|\| PPC64 \|\| S390
	help
	The hangcheck-timer module detects when the system has gone
	out to lunch past a certain margin. It can reboot the system
	or merely print a warning.

	config MMTIMER
	tristate "MMTIMER Memory mapped RTC for SGI Altix"
	depends on IA64_GENERIC \|\| IA64_SGI_SN2
	default y
	help
	The mmtimer device allows direct userspace access to the
	Altix system timer.

	config UV_MMTIMER
	tristate "UV_MMTIMER Memory mapped RTC for SGI UV"
	depends on X86_UV
	default m
	help
	The uv_mmtimer device allows direct userspace access to the
	UV system timer.

	source "drivers/char/tpm/Kconfig"

	config TELCLOCK
	tristate "Telecom clock driver for ATCA SBC"
	depends on X86
	default n
	help
	The telecom clock device is specific to the MPCBL0010 and MPCBL0050
	ATCA computers and allows direct userspace access to the
	configuration of the telecom clock configuration settings. This
	device is used for hardware synchronization across the ATCA backplane
	fabric. Upon loading, the driver exports a sysfs directory,
	/sys/devices/platform/telco_clock, with a number of files for
	controlling the behavior of this hardware.

	config DEVPORT
	bool
	depends on ISA \|\| PCI
	default y

	source "drivers/s390/char/Kconfig"

	config TILE_SROM
	bool "Character-device access via hypervisor to the Tilera SPI ROM"
	depends on TILE
	default y
	---help---
	This device provides character-level read-write access
	to the SROM, typically via the "0", "1", and "2" devices
	in /dev/srom/. The Tilera hypervisor makes the flash
	device appear much like a simple EEPROM, and knows
	how to partition a single ROM for multiple purposes.

	source "drivers/char/xillybus/Kconfig"

	endmenu