tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
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Documentation/ABI/testing/gpio-cdev
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Documentation/ABI/testing/gpio-cdev
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What: /dev/gpiochip[0-9]+
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Date: November 2015
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KernelVersion: 4.4
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Contact: linux-gpio@vger.kernel.org
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Description:
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The character device files /dev/gpiochip* are the interface
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between GPIO chips and userspace.
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The ioctl(2)-based ABI is defined and documented in
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[include/uapi]<linux/gpio.h>.
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The following file operations are supported:
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open(2)
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Currently the only useful flags are O_RDWR.
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ioctl(2)
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Initiate various actions.
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See the inline documentation in [include/uapi]<linux/gpio.h>
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for descriptions of all ioctls.
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close(2)
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Stops and free up the I/O contexts that was associated
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with the file descriptor.
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Users: TBD
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