skge: use per-port phy locking

[powerpc.git] / Documentation / gpio.txt

diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 576ce46..989f113 100644 (file)
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -105,12 +105,15 @@ setting up a platform_device using the GPIO, is mark its direction:
 
        /* set as input or output, returning 0 or negative errno */
        int gpio_direction_input(unsigned gpio);
-       int gpio_direction_output(unsigned gpio);
+       int gpio_direction_output(unsigned gpio, int value);
 
 The return value is zero for success, else a negative errno.  It should
 be checked, since the get/set calls don't have error returns and since
 misconfiguration is possible.  (These calls could sleep.)
 
+For output GPIOs, the value provided becomes the initial output value.
+This helps avoid signal glitching during system startup.
+
 Setting the direction can fail if the GPIO number is invalid, or when
 that particular GPIO can't be used in that mode.  It's generally a bad
 idea to rely on boot firmware to have set the direction correctly, since