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