This patch describes the GPIO lines usage on the Odroid-C2 board.

This is useful in the debugfs gpio file and using the cdev gpio API.
Signed-off-by: NNeil Armstrong <narmstrong@baylibre.com>
Reviewed-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NKevin Hilman <khilman@baylibre.com>