[PATCH V3 1/2] dt-bindings: add matrix keypad documentation

@@ -0,0 +1,55 @@
+* Mediatek's Keypad Controller device tree binding
+
+Mediatek's Keypad controller is used to interface a SoC with a matrix-type
+keypad device. The keypad controller supports multiple row and column lines.
+A key can be placed at each intersection of a unique row and a unique column.
+The keypad controller can sense a key-press and key-release and report the
+event using a interrupt to the cpu.
+
+Required properties:
+- compatible should contain:
+	* "mediatek,kp" for common keypad
+
+- reg: The base address of the Keypad register bank.
+
+- interrupts: A single interrupt specifier.
+
+- mediatek,debounce-us: Debounce interval in microseconds, maximum value
+  is 256000ms
+
+- keypad,num-rows: Number of row lines connected to the keypad controller
+
+- keypad,num-columns: Number of column lines connected to the keypad controller
+
+- linux,keymap: The keymap for keys as described in the binding document
+  devicetree/bindings/input/matrix-keymap.txt.
+
+- pinctrl: Should specify pin control groups used for this controller.
+  See ../pinctrl/pinctrl-bindings.txt for details.
+
+- clocks: Must contain one entry, for the module clock.
+  See ../clocks/clock-bindings.txt for details.
+
+Optional Properties:
+- wakeup-source: use any event on keypad as wakeup event.
+
+Example:
+
+	keypad: kp@10010000 {
+		compatible = "mediatek,kp";
+		reg = <0 0x10010000 0 0x1000>;
+		wakeup-source;
+		interrupts = <GIC_SPI 75 IRQ_TYPE_EDGE_FALLING>;
+		clocks = <&clk26m>;
+		clock-names = "kpd";
+	};
+
+	&keypad {
+		mediatek,debounce-us = <32000>;
+		keypad,num-rows = <8>;
+		keypad,num-columns = <9>;
+		linux,keymap = < MATRIX_KEY(0x00, 0x00, KEY_VOLUMEDOWN) >;
+		status = "okay";
+		pinctrl-names = "default";
+		pinctrl-0 = <&kpd_gpios_def_cfg>;
+	};