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| author | Linus Walleij <linus.walleij@linaro.org> | 2015-10-22 10:21:57 +0200 |
|---|---|---|
| committer | Linus Walleij <linus.walleij@linaro.org> | 2016-02-09 11:09:52 +0100 |
| commit | 40c159b776f882f2e2cbe20c9e29832841e5c0f9 (patch) | |
| tree | 393e6f31deddd2928911784e2d3082c11baf74de /Documentation/ABI/testing/gpio-cdev | |
| parent | tools/gpio: create GPIO tools (diff) | |
| download | linux-40c159b776f882f2e2cbe20c9e29832841e5c0f9.tar.xz linux-40c159b776f882f2e2cbe20c9e29832841e5c0f9.zip | |
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/ABI/testing/gpio-cdev')
| -rw-r--r-- | Documentation/ABI/testing/gpio-cdev | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/gpio-cdev b/Documentation/ABI/testing/gpio-cdev new file mode 100644 index 000000000000..7b265fbb47e3 --- /dev/null +++ b/Documentation/ABI/testing/gpio-cdev @@ -0,0 +1,26 @@ +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 |