pwm: jz4740: Add support for devicetree

Add support for probing the pwm-jz4740 directly from devicetree.

Signed-off-by: Paul Cercueil <paul@crapouillou.net>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>

Documentation/devicetree/bindings/pwm/ingenic,jz47xx-pwm.txt

@@ -0,0 +1,25 @@
+Ingenic JZ47xx PWM Controller
+=============================
+
+Required properties:
+- compatible: One of:
+  * "ingenic,jz4740-pwm"
+  * "ingenic,jz4770-pwm"
+  * "ingenic,jz4780-pwm"
+- #pwm-cells: Should be 3. See pwm.txt in this directory for a description
+  of the cells format.
+- clocks : phandle to the external clock.
+- clock-names : Should be "ext".
+
+
+Example:
+
+	pwm: pwm@10002000 {
+		compatible = "ingenic,jz4740-pwm";
+		reg = <0x10002000 0x1000>;
+
+		#pwm-cells = <3>;
+
+		clocks = <&ext>;
+		clock-names = "ext";
+	};