gpio calls don't need i/o barriers
Clarify that drivers using the GPIO operations don't need to issue io
barrier instructions themselves. Previously this wasn't clear, and at
least one platform assumed otherwise (and would thus break various
otherwise-portable drivers which don't issue barriers).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 36af58e..218a865 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -75,6 +75,9 @@
If you stick to this convention then it'll be easier for other developers to
see what your code is doing, and help maintain it.
+Note that these operations include I/O barriers on platforms which need to
+use them; drivers don't need to add them explicitly.
+
Identifying GPIOs
-----------------
