linux.git/include/asm-generic/gpio.h, branch v2.6.36

gpio: doc updates

2010-09-10T01:57:24+00:00

There's been some recent confusion about error checking GPIO numbers.
briefly, it should be handled mostly during setup, when gpio_request() is
called, and NEVER by expectig gpio_is_valid to report more than
never-usable GPIO numbers.

[akpm@linux-foundation.org: terminate unterminated comment]
Signed-off-by: David Brownell 
Cc: Eric Miao" 
Cc: "Ryan Mallon" 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

of/gpio: stop using device_node data pointer to find gpio_chip

2010-07-05T22:14:30+00:00

Currently the kernel uses the struct device_node.data pointer to resolve
a struct gpio_chip pointer from a device tree node.  However, the .data
member doesn't provide any type checking and there aren't any rules
enforced on what it should be used for.  There's no guarantee that the
data stored in it actually points to an gpio_chip pointer.

Instead of relying on the .data pointer, this patch modifies the code
to add a lookup function which scans through the registered gpio_chips
and returns the gpio_chip that has a pointer to the specified
device_node.

Signed-off-by: Grant Likely 
CC: Andrew Morton 
CC: Anton Vorontsov 
CC: Grant Likely 
CC: David Brownell 
CC: Bill Gatliff 
CC: Dmitry Eremin-Solenikov 
CC: Benjamin Herrenschmidt 
CC: Jean Delvare 
CC: linux-kernel@vger.kernel.org
CC: devicetree-discuss@lists.ozlabs.org

of/gpio: Kill of_gpio_chip and add members directly to gpio_chip

2010-07-05T22:14:30+00:00

The OF gpio infrastructure is great for describing GPIO connections within
the device tree.  However, using a GPIO binding still requires changes to
the gpio controller just to add an of_gpio structure.  In most cases, the
gpio controller doesn't actually need any special support and the simple
OF gpio mapping function is more than sufficient.  Additional, the current
scheme of using of_gpio_chip requires a convoluted scheme to maintain
1:1 mappings between of_gpio_chip and gpio_chip instances.

If the struct of_gpio_chip data members were moved into struct gpio_chip,
then it would simplify the processing of OF gpio bindings, and it would
make it trivial to use device tree OF connections on existing gpiolib
controller drivers.

This patch eliminates the of_gpio_chip structure and moves the relevant
fields into struct gpio_chip (conditional on CONFIG_OF_GPIO).  This move
simplifies the existing code and prepares for adding automatic device tree
support to existing drivers.

Signed-off-by: Grant Likely 
Cc: Andrew Morton 
Cc: Anton Vorontsov 
Cc: Grant Likely 
Cc: David Brownell 
Cc: Bill Gatliff 
Cc: Dmitry Eremin-Solenikov 
Cc: Benjamin Herrenschmidt 
Cc: Jean Delvare

gpiolib: introduce set_debounce method

2010-05-27T16:12:42+00:00

A few architectures, like OMAP, allow you to set a debouncing time for the
gpio before generating the IRQ.  Teach gpiolib about that.

Mark said:
: This would be generally useful for embedded systems, especially where
: the interrupt concerned is a wake source.  It allows drivers to avoid
: spurious interrupts from noisy sources so if the hardware supports it
: the driver can avoid having to explicitly wait for the signal to become
: stable and software has to cope with fewer events.  We've lived without
: it for quite some time, though.

David said:
: I looked at adding debounce support to the generic GPIO calls (and thus
: gpiolib) some time back, but decided against it.  I forget why at this
: time (check list archives) but it wasn't because of lack of utility in
: certain contexts.
:
: One thing to watch out for is just how variable the hardware capabilities
: are.  Atmel GPIOs have something like a fixed number of 32K clock cycles
: for debounce, twl4030 had something odd, OMAPs were more like the Atmel
: chips but with a different clock.  In some cases debouncing had to be
: ganged, not per-GPIO.  And so forth.

Signed-off-by: Felipe Balbi 
Cc: Tony Lindgren 
Cc: David Brownell 
Reviewed-by: Mark Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiolib: document that names can contain printk format specifiers

2010-05-27T16:12:41+00:00

Signed-off-by: Uwe Kleine-König 
Cc: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiolib: make names array and its values const

2010-05-27T16:12:41+00:00

gpiolib doesn't need to modify the names and I assume most initializers
use string constants that shouldn't be modified anyhow.

[akpm@linux-foundation.org: fix drivers/gpio/cs5535-gpio.c]
Signed-off-by: Uwe Kleine-König 
Cc: Kevin Wells 
Cc: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpio: introduce gpio_request_one() and friends

2010-03-06T19:26:48+00:00

gpio_request() without initial configuration of the GPIO is normally
useless, introduce gpio_request_one() together with GPIOF_ flags for
input/output direction and initial output level.

gpio_{request,free}_array() for multiple GPIOs.

Signed-off-by: Eric Miao 
Cc: David Brownell 
Cc: Ben Nizette 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

gpiolib: add support for changing value polarity in sysfs

2009-12-16T15:20:01+00:00

Drivers may use gpiolib sysfs as part of their public user space
interface. The GPIO number and polarity might change from board to
board. The gpio_export_link() call can be used to hide the GPIO number
from user space. Add support for also hiding the GPIO line polarity
changes from user space.

Signed-off-by: Jani Nikula 
Cc: David Brownell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

asm-generic/gpio.h: add some forward decls of the device struct

2009-12-10T21:18:33+00:00

After the recent commit a4177ee7f, attempting to include asm-generic/gpio.h
in otherwise "slim" code results in ugly warnings like so:

  CC      arch/blackfin/kernel/bfin_gpio.o
In file included from arch/blackfin/include/asm/gpio.h:278,
                 from arch/blackfin/kernel/bfin_gpio.c:15:
include/asm-generic/gpio.h:193: warning:
‘struct device’ declared inside parameter list
its scope is only this definition or declaration, which is probably not what you want

So add simple C forward decls of the struct device to avoid these.

Signed-off-by: Mike Frysinger 
Signed-off-by: Arnd Bergmann

asm-generic/gpio.h: pull in linux/kernel.h for might_sleep()

2009-10-01T23:11:11+00:00

The asm-generic/gpio.h header uses the might_sleep() macro but doesn't
include the header for it, so any source code that might include
linux/gpio.h before linux/kernel.h can easily lead to a build failure.

Signed-off-by: Mike Frysinger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds