Documentation/ABI/testing/gpio-cdev

   1 What:           /dev/gpiochip[0-9]+
   2 Date:           November 2015
   3 KernelVersion:  4.4
   4 Contact:        linux-gpio@vger.kernel.org
   5 Description:
   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 and documented in
  10                 [include/uapi]<linux/gpio.h>.
  11
  12                 The following file operations are supported:
  13
  14                 open(2)
  15                 Currently the only useful flags are O_RDWR.
  16
  17                 ioctl(2)
  18                 Initiate various actions.
  19                 See the inline documentation in [include/uapi]<linux/gpio.h>
  20                 for descriptions of all ioctls.
  21
  22                 close(2)
  23                 Stops and free up the I/O contexts that was associated
  24                 with the file descriptor.
  25
  26 Users:          TBD