140c159b7SLinus WalleijWhat: /dev/gpiochip[0-9]+ 240c159b7SLinus WalleijDate: November 2015 340c159b7SLinus WalleijKernelVersion: 4.4 440c159b7SLinus WalleijContact: linux-gpio@vger.kernel.org 540c159b7SLinus WalleijDescription: 640c159b7SLinus Walleij The character device files /dev/gpiochip* are the interface 740c159b7SLinus Walleij between GPIO chips and userspace. 840c159b7SLinus Walleij 9*c27cdd7aSKent Gibson The ioctl(2)-based ABI is defined in 10*c27cdd7aSKent Gibson [include/uapi]<linux/gpio.h> and documented in 11*c27cdd7aSKent Gibson Documentation/userspace-api/gpio/chardev.rst. 1240c159b7SLinus Walleij 1340c159b7SLinus Walleij The following file operations are supported: 1440c159b7SLinus Walleij 1540c159b7SLinus Walleij open(2) 1640c159b7SLinus Walleij Currently the only useful flags are O_RDWR. 1740c159b7SLinus Walleij 1840c159b7SLinus Walleij ioctl(2) 1940c159b7SLinus Walleij Initiate various actions. 2054a19b4dSMauro Carvalho Chehab 21*c27cdd7aSKent Gibson See Documentation/userspace-api/gpio/chardev.rst 22*c27cdd7aSKent Gibson for a description of all ioctls. 2340c159b7SLinus Walleij 2440c159b7SLinus Walleij close(2) 2540c159b7SLinus Walleij Stops and free up the I/O contexts that was associated 2640c159b7SLinus Walleij with the file descriptor. 2740c159b7SLinus Walleij 2840c159b7SLinus WalleijUsers: TBD 29