--- zzzz-none-000/linux-3.10.107/Documentation/devicetree/bindings/arm/twd.txt	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/Documentation/devicetree/bindings/arm/twd.txt	2021-02-04 17:41:59.000000000 +0000
@@ -19,6 +19,11 @@
 - reg : Specify the base address and the size of the TWD timer
 	register window.
 
+Optional
+
+- always-on : a boolean property. If present, the timer is powered through
+  an always-on power domain, therefore it never loses context.
+
 Example:
 
 	twd-timer@2c000600 {