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gpio: add a userspace character device ABI 

Put in some documentation for the new character device ABI
so we can properly etch it in stone.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Linus Walleij 2015-10-22 10:21:57 +02:00
parent 6d591c46bc
commit 40c159b776
2 changed files with 27 additions and 0 deletions
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26
Documentation/ABI/testing/gpio-cdev Normal file
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What: /dev/gpiochip[0-9]+
Date: November 2015
KernelVersion: 4.4
Contact: linux-gpio@vger.kernel.org
Description:
The character device files /dev/gpiochip* are the interface
between GPIO chips and userspace.
The ioctl(2)-based ABI is defined and documented in
[include/uapi]<linux/gpio.h>.
The following file operations are supported:
open(2)
Currently the only useful flags are O_RDWR.
ioctl(2)
Initiate various actions.
See the inline documentation in [include/uapi]<linux/gpio.h>
for descriptions of all ioctls.
close(2)
Stops and free up the I/O contexts that was associated
with the file descriptor.
Users: TBD

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MAINTAINERS
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@ -4815,6 +4815,7 @@ L: linux-gpio@vger.kernel.org
T: git git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-gpio.git
S: Maintained
F: Documentation/gpio/
F: Documentation/ABI/testing/gpio-cdev
F: drivers/gpio/
F: include/linux/gpio/
F: include/linux/gpio.h