Commit 40c159b7 authored by Linus Walleij's avatar Linus Walleij
Browse files

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: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 6d591c46

Documentation/ABI/testing/gpio-cdev

0 → 100644
+26 −0
Original line number Diff line number Diff line 
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

MAINTAINERS

+1 −0
Original line number Diff line number Diff line
@@ -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