gpio/ABI: document what is already the case

commit 1f6709984736c5d5de748db5918416da65ee0d4c
"gpiolib: allow GPIOs to be named" added the ability to
name GPIO lines by an array of names stored in the GPIO
chip. This was in 2009 and has been an ABI since. Let's
document it properly.

Cc: Daniel Silverstone <dsilvers@digital-scurf.org>
Cc: Markus Pargmann <mpa@pengutronix.de>
Cc: Johan Hovold <johan@kernel.org>
Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/Documentation/ABI/testing/sysfs-gpio b/Documentation/ABI/testing/sysfs-gpio
index 80f4c94c7befdc67e9ecfec2753238ee7811bc1b..55ffa2df1c10225ee01c38a7fb41334cd949286f 100644 (file)
--- a/Documentation/ABI/testing/sysfs-gpio
+++ b/Documentation/ABI/testing/sysfs-gpio
@@ -16,7 +16,8 @@ Description:
     /sys/class/gpio
        /export ... asks the kernel to export a GPIO to userspace
        /unexport ... to return a GPIO to the kernel
-       /gpioN ... for each exported GPIO #N
+       /gpioN ... for each exported GPIO #N OR
+       /<LINE-NAME> ... for a properly named GPIO line
            /value ... always readable, writes fail for input GPIOs
            /direction ... r/w as: in, out (default low); write: high, low
            /edge ... r/w as: none, falling, rising, both