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gpio/ABI: document what is already the case

Message ID 1439200817-7268-1-git-send-email-linus.walleij@linaro.org
State Accepted
Commit 77a775b7ccaf86b0bb67ceaaf3b6d2720e12b506
Headers show

Commit Message

Linus Walleij Aug. 10, 2015, 10 a.m. UTC
commit 926b663ce8215ba448960e1ff6e58b67a2c3b99b
"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>
---
This flat namespace does not allow two GPIO lines to have
the same name, sadly. Now I can not do anything about it,
it is just so.
---
 Documentation/ABI/testing/sysfs-gpio | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
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Patch

diff --git a/Documentation/ABI/testing/sysfs-gpio b/Documentation/ABI/testing/sysfs-gpio
index 80f4c94c7bef..55ffa2df1c10 100644
--- 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