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 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
  28 Users:          TBD