Document: devicetree: input: imx: i.mx snvs power device tree bindings

The snvs-pwrkey is designed to enable POWER key function which controlled
by SNVS ONOFF. the driver can report the status of POWER key and wakeup
system if pressed after system suspend.

Signed-off-by: Frank Li <Frank.Li@freescale.com>
Signed-off-by: Robin Gong <b38343@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>

Documentation/devicetree/bindings/crypto/fsl-sec4.txt

@@ -386,6 +386,47 @@ EXAMPLE
 		offset = <0x34>;
 	};
 
+=====================================================================
+System ON/OFF key driver
+
+  The snvs-pwrkey is designed to enable POWER key function which controlled
+  by SNVS ONOFF, the driver can report the status of POWER key and wakeup
+  system if pressed after system suspend.
+
+  - compatible:
+      Usage: required
+      Value type: <string>
+      Definition: Mush include "fsl,sec-v4.0-pwrkey".
+
+  - interrupts:
+      Usage: required
+      Value type: <prop_encoded-array>
+      Definition: The SNVS ON/OFF interrupt number to the CPU(s).
+
+  - linux,keycode:
+      Usage: option
+      Value type: <int>
+      Definition: Keycode to emit, KEY_POWER by default.
+
+  - wakeup:
+      Usage: option
+      Value type: <boo>
+      Definition: Button can wake-up the system.
+
+ - regmap:
+      Usage: required:
+      Value type: <phandle>
+      Definition: this is phandle to the register map node.
+
+EXAMPLE:
+	snvs-pwrkey@0x020cc000 {
+		compatible = "fsl,sec-v4.0-pwrkey";
+		regmap = <&snvs>;
+		interrupts = <0 4 0x4>
+	        linux,keycode = <116>; /* KEY_POWER */
+		wakeup;
+	};
+
 =====================================================================
 FULL EXAMPLE
 
@@ -466,6 +507,14 @@ FULL EXAMPLE
 			offset = <0x34>;
 			interrupts = <93 2>;
 		};
+
+		snvs-pwrkey@0x020cc000 {
+			compatible = "fsl,sec-v4.0-pwrkey";
+			regmap = <&sec_mon>;
+			interrupts = <0 4 0x4>;
+			linux,keycode = <116>; /* KEY_POWER */
+			wakeup;
+		};
 	};
 
 =====================================================================

Documentation/devicetree/bindings/input/snvs-pwrkey.txt

@@ -0,0 +1 @@
+See Documentation/devicetree/bindings/crypto/fsl-sec4.txt