diff --git a/Documentation/devicetree/bindings/input/ads7846.txt b/Documentation/devicetree/bindings/input/ads7846.txt
index 33a1638..c6cfe2e 100644
--- a/Documentation/devicetree/bindings/input/ads7846.txt
+++ b/Documentation/devicetree/bindings/input/ads7846.txt
@@ -29,6 +29,8 @@
 	ti,vref-delay-usecs		vref supply delay in usecs, 0 for
 					external vref (u16).
 	ti,vref-mv			The VREF voltage, in millivolts (u16).
+					Set to 0 to use internal refernce
+					(ADS7846).
 	ti,keep-vref-on			set to keep vref on for differential
 					measurements as well
 	ti,swap-xy			swap x and y axis