1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/gpio.txt b/Documentation/gpio.txt
index 566edaa56a53..fa4dc077ae0e 100644
--- a/Documentation/gpio.txt
+++ b/Documentation/gpio.txt
@@ -524,6 +524,13 @@ and have the following read/write attributes:
                 is configured as an output, this value may be written;
                 any nonzero value is treated as high.
 
+        "edge" ... reads as either "none", "rising", "falling", or
+                "both". Write these strings to select the signal edge(s)
+                that will make poll(2) on the "value" file return.
+
+                This file exists only if the pin can be configured as an
+                interrupt generating input pin.
+
 GPIO controllers have paths like /sys/class/gpio/chipchip42/ (for the
 controller implementing GPIOs starting at #42) and have the following
 read-only attributes: