gpio-cdev

 1What:		/dev/gpiochip[0-9]+
 2Date:		November 2015
 3KernelVersion:	4.4
 4Contact:	linux-gpio@vger.kernel.org
 5Description:
 6		The character device files /dev/gpiochip* are the interface
 7		between GPIO chips and userspace.
 8
 9		The ioctl(2)-based ABI is defined in
10		[include/uapi]<linux/gpio.h> and documented in
11		Documentation/userspace-api/gpio/chardev.rst.
12
13		The following file operations are supported:
14
15		open(2)
16		  Currently the only useful flags are O_RDWR.
17
18		ioctl(2)
19		  Initiate various actions.
20
21		  See Documentation/userspace-api/gpio/chardev.rst
22		  for a description of all ioctls.
23
24		close(2)
25		  Stops and free up the I/O contexts that was associated
26		  with the file descriptor.
27
28Users:		TBD