diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 36af58eba136bac198ea3b1f33f34236be9ce5df..218a8650f48dea441ce4b5777416f028fff518f8 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -75,6 +75,9 @@ using the include file:
 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
 -----------------