Searching for information on using the GPIO has been fairly daunting. The user docs refer the the https://github.com/torvalds/linux/blob/master/drivers/pinctrl/intel/pinctrl-cherryview.c Cherryview driver which refers to the code and the use of sysfs interface https://www.kernel.org/doc/Documentation/gpio/sysfs.txt, which has been depreciated in favor of libgpiod, https://git.kernel.org/pub/scm/libs/libgpiod/libgpiod.git/. I had trouble getting the sysfs commands to work until I found the forum thread which indicated that sudo doesn't work right and the commands should be in the format: echo xxx | sudo tee /sys/class/gpio/export. The libgpiod brings several commands for CLI manipulation:gpiodetect, gpiofind, gpioget, gpioinfo, gpiomon and gpioset. It requires sudo and a knowledge of the new structure. There are 4 "gpio" chips which control the gpio pins as well as the Uart, and i2c ports.