--- zzzz-none-000/linux-3.10.107/Documentation/devicetree/bindings/input/gpio-keys-polled.txt	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/Documentation/devicetree/bindings/input/gpio-keys-polled.txt	2021-02-04 17:41:59.000000000 +0000
@@ -13,14 +13,22 @@
 
 	- gpios: OF device-tree gpio specification.
 	- label: Descriptive name of the key.
-	- linux,code: Keycode to emit.
+	- linux,code: Key / Axis code to emit.
 
 Optional subnode-properties:
 	- linux,input-type: Specify event type this button/key generates.
 	  If not specified defaults to <1> == EV_KEY.
+	- linux,input-value: If linux,input-type is EV_ABS or EV_REL then this
+	  value is sent for events this button generates when pressed.
+	  EV_ABS/EV_REL axis will generate an event with a value of 0 when
+	  all buttons with linux,input-type == type and linux,code == axis
+	  are released. This value is interpreted as a signed 32 bit value,
+	  e.g. to make a button generate a value of -1 use:
+	  linux,input-value = <0xffffffff>; /* -1 */
 	- debounce-interval: Debouncing interval time in milliseconds.
 	  If not specified defaults to 5.
-	- gpio-key,wakeup: Boolean, button can wake-up the system.
+	- wakeup-source: Boolean, button can wake-up the system.
+			 (Legacy property supported: "gpio-key,wakeup")
 
 Example nodes: