Input: add document for rockchip keys

Change-Id: I3f8f4522e6279e3f5faf3f293936c835ce8fc6b7
Signed-off-by: Jianqun Xu <jay.xu@rock-chips.com>

diff --git a/Documentation/devicetree/bindings/input/rockchip-keys.txt b/Documentation/devicetree/bindings/input/rockchip-keys.txt
new file mode 100644 (file)
index 0000000..7b3fba3
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/rockchip-keys.txt
@@ -0,0 +1,69 @@
+ROCKCHIP ADC attached resistor ladder buttons
+------------------------------------
+
+Required properties:
+ - compatible: "rockchip,key"
+ - io-channels: Phandle to an ADC channel
+
+Each button (key) is represented as a sub-node of "rockchip,key":
+
+Required subnode-properties:
+       - label: Descriptive name of the key.
+       - linux,code: Keycode to emit.
+       - rockchip,adc_value:: Voltage ADC input when this key is pressed.
+
+Example:
+
+#include <dt-bindings/input/input.h>
+
+       rk_key: rockchip-key {
+               compatible = "rockchip,key";
+               status = "okay";
+
+               io-channels = <&saradc 1>;
+
+               vol-up-key {
+                       linux,code = <115>;
+                       label = "volume up";
+                       rockchip,adc_value = <1>;
+               };
+
+               vol-down-key {
+                       linux,code = <114>;
+                       label = "volume down";
+                       rockchip,adc_value = <170>;
+               };
+
+               power-key {
+                       gpios = <&gpio0 5 GPIO_ACTIVE_LOW>;
+                       linux,code = <116>;
+                       pinctrl-names = "default";
+                       pinctrl-0 = <&pwrbtn>;
+                       label = "power";
+                       gpio-key,wakeup;
+               };
+
+               menu-key {
+                       linux,code = <59>;
+                       label = "menu";
+                       rockchip,adc_value = <355>;
+               };
+
+               home-key {
+                       linux,code = <102>;
+                       label = "home";
+                       rockchip,adc_value = <746>;
+               };
+
+               back-key {
+                       linux,code = <158>;
+                       label = "back";
+                       rockchip,adc_value = <560>;
+               };
+
+               camera-key {
+                       linux,code = <212>;
+                       label = "camera";
+                       rockchip,adc_value = <450>;
+               };
+       };