linux.git/include/asm-generic/gpio.h, branch v2.6.31

gpiolib: allow GPIOs to be named

2009-04-03T02:04:51+00:00

Allow GPIOs in GPIOLIB chips to be named.  This name is then used when the
GPIO is exported to sysfs, although it could be used elsewhere if deemed
useful.

Signed-off-by: Daniel Silverstone 
Cc: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiolib: request/free hooks

2008-10-16T18:21:40+00:00

Add a new internal mechanism to gpiolib to support low power
operations by letting gpio_chip instances see when their GPIOs
are in use.  When no GPIOs are active, chips may be able to
enter lower powered runtime states by disabling clocks and/or
power domains.

Signed-off-by: David Brownell 
Cc: "Magnus Damm" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiolib: gpio_to_irq() hooks

2008-10-16T18:21:40+00:00

Add a new gpiolib mechanism: gpio_chip instances can provide mappings
between their (input) GPIOs and any associated IRQs.  This makes it easier
for platforms to support IRQs that are provided by board-specific external
chips instead of as part of their core (such as SOC-integrated GPIOs).

Also update the irq_to_gpio() description, saying to avoid it because it's
not always supported.

Signed-off-by: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpio: make gpiochip label const

2008-10-16T18:21:40+00:00

Mark gpiochip label as a const char pointer.  Fixes things like

arch/arm/common/scoop.c: In function `scoop_probe':
arch/arm/common/scoop.c:250: warning: assignment discards qualifiers from pointer target type

Signed-off-by: Dmitry Baryshkov 
Acked-by: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpio: fix build on CONFIG_GPIO_SYSFS=n

2008-07-28T23:30:21+00:00

If CONFIG_GENERIC_GPIO=y && CONFIG_GPIO_SYSFS=n, gpio_export() in
asm-generic/gpio.h refers -ENOSYS and causes build error.

Signed-off-by: Atsushi Nemoto 
Acked-by: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiolib: fix typo in comment

2008-07-27T03:16:47+00:00

This fixes an off-by-one error in a comment.

Signed-off-by: Michael Buesch 
Cc: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiolib: allow user-selection

2008-07-25T17:53:30+00:00

This patch adds functionality to the gpio-lib subsystem to make it
possible to enable the gpio-lib code even if the architecture code didn't
request to get it built in.

The archtitecture code does still need to implement the gpiolib accessor
functions in its asm/gpio.h file.  This patch adds the implementations for
x86 and PPC.

With these changes it is possible to run generic GPIO expansion cards on
every architecture that implements the trivial wrapper functions.  Support
for more architectures can easily be added.

Signed-off-by: Michael Buesch 
Cc: Benjamin Herrenschmidt 
Cc: Stephen Rothwell 
Cc: David Brownell 
Cc: Russell King 
Cc: Haavard Skinnemoen 
Cc: Jesper Nilsson 
Cc: Ralf Baechle 
Cc: Paul Mackerras 
Cc: Benjamin Herrenschmidt 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: Jean Delvare 
Cc: Samuel Ortiz 
Cc: Kumar Gala 
Cc: Sam Ravnborg 
Cc: Adrian Bunk 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpio: sysfs interface

2008-07-25T17:53:30+00:00

This adds a simple sysfs interface for GPIOs.

    /sys/class/gpio
    	/export ... asks the kernel to export a GPIO to userspace
    	/unexport ... to return a GPIO to the kernel
        /gpioN ... for each exported GPIO #N
	    /value ... always readable, writes fail for input GPIOs
	    /direction ... r/w as: in, out (default low); write high, low
	/gpiochipN ... for each gpiochip; #N is its first GPIO
	    /base ... (r/o) same as N
	    /label ... (r/o) descriptive, not necessarily unique
	    /ngpio ... (r/o) number of GPIOs; numbered N .. N+(ngpio - 1)

GPIOs claimed by kernel code may be exported by its owner using a new
gpio_export() call, which should be most useful for driver debugging.
Such exports may optionally be done without a "direction" attribute.

Userspace may ask to take over a GPIO by writing to a sysfs control file,
helping to cope with incomplete board support or other "one-off"
requirements that don't merit full kernel support:

  echo 23 > /sys/class/gpio/export
	... will gpio_request(23, "sysfs") and gpio_export(23);
	use /sys/class/gpio/gpio-23/direction to (re)configure it,
	when that GPIO can be used as both input and output.
  echo 23 > /sys/class/gpio/unexport
	... will gpio_free(23), when it was exported as above

The extra D-space footprint is a few hundred bytes, except for the sysfs
resources associated with each exported GPIO.  The additional I-space
footprint is about two thirds of the current size of gpiolib (!).  Since
no /dev node creation is involved, no "udev" support is needed.

Related changes:

  * This adds a device pointer to "struct gpio_chip".  When GPIO
    providers initialize that, sysfs gpio class devices become children of
    that device instead of being "virtual" devices.

  * The (few) gpio_chip providers which have such a device node have
    been updated.

  * Some gpio_chip drivers also needed to update their module "owner"
    field ...  for which missing kerneldoc was added.

  * Some gpio_chips don't support input GPIOs.  Those GPIOs are now
    flagged appropriately when the chip is registered.

Based on previous patches, and discussion both on and off LKML.

A Documentation/ABI/testing/sysfs-gpio update is ready to submit once this
merges to mainline.

[akpm@linux-foundation.org: a few maintenance build fixes]
Signed-off-by: David Brownell 
Cc: Guennadi Liakhovetski 
Cc: Greg KH 
Cc: Kay Sievers 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpio: build fixes

2008-05-24T16:56:13+00:00

This fixes various gpio-related build errors (mostly potential)
reported in part by Russell King and Uwe Kleine-König.

Signed-off-by: David Brownell 
Cc: Uwe Kleine-König 
Cc: Russell King 
Cc: Arnaud Patard 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiochip_reserve()

2008-04-28T15:58:34+00:00

Add a new function gpiochip_reserve() to reserve ranges of gpios that platform
code has pre-allocated.  That is, this marks gpio numbers which will be
claimed by drivers that haven't yet been loaded, and thus are not available
for dynamic gpio number allocation.

[akpm@linux-foundation.org: remove unneeded __must_check]
[david-b@pacbell.net: don't export gpiochip_reserve (section fix)]
Signed-off-by: Anton Vorontsov 
Signed-off-by: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds