linux/Documentation/ABI/testing/gpio-cdev

What:		/dev/gpiochip[0-9]+
Date:		November 2015
KernelVersion:	4.4
Contact:	[email protected]
Description:
		The character device files /dev/gpiochip* are the interface
		between GPIO chips and userspace.

		The ioctl(2)-based ABI is defined in
		[include/uapi]<linux/gpio.h> and documented in
		Documentation/userspace-api/gpio/chardev.rst.

		The following file operations are supported:

		open(2)
		  Currently the only useful flags are O_RDWR.

		ioctl(2)
		  Initiate various actions.

		  See Documentation/userspace-api/gpio/chardev.rst
		  for a description of all ioctls.

		close(2)
		  Stops and free up the I/O contexts that was associated
		  with the file descriptor.

Users:		TBD