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authorLinus Walleij <linus.walleij@linaro.org>2015-10-22 08:21:57 (GMT)
committerLinus Walleij <linus.walleij@linaro.org>2016-02-09 10:09:52 (GMT)
commit40c159b776f882f2e2cbe20c9e29832841e5c0f9 (patch)
tree393e6f31deddd2928911784e2d3082c11baf74de /Documentation
parent6d591c46bce037696d173bd5c8461b2b4bb680ad (diff)
downloadlinux-40c159b776f882f2e2cbe20c9e29832841e5c0f9.tar.xz
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>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/gpio-cdev26
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diff --git a/Documentation/ABI/testing/gpio-cdev b/Documentation/ABI/testing/gpio-cdev
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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