1 files changed, 7 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/pps/pps-gpio.txt b/Documentation/devicetree/bindings/pps/pps-gpio.txt
index 3683874832ae..9012a2a02e14 100644
--- a/Documentation/devicetree/bindings/pps/pps-gpio.txt
+++ b/Documentation/devicetree/bindings/pps/pps-gpio.txt
@@ -7,6 +7,10 @@ Required properties:
 - compatible: should be "pps-gpio"
 - gpios: one PPS GPIO in the format described by ../gpio/gpio.txt
 
+Additional required properties for the PPS ECHO functionality:
+- echo-gpios: one PPS ECHO GPIO in the format described by ../gpio/gpio.txt
+- echo-active-ms: duration in ms of the active portion of the echo pulse
+
 Optional properties:
 - assert-falling-edge: when present, assert is indicated by a falling edge
                        (instead of by a rising edge)
@@ -19,5 +23,8 @@ Example:
                 gpios = <&gpio1 26 GPIO_ACTIVE_HIGH>;
                 assert-falling-edge;
 
+                echo-gpios = <&gpio1 27 GPIO_ACTIVE_HIGH>;
+                echo-active-ms = <100>;
+
                 compatible = "pps-gpio";
         };