ARM: dts: OMAP: Add counter-32k nodes

Adds the counter-32k timers nodes present in OMAP2/3/4 devices and
device-tree binding documentation for OMAP counter-32k.
Signed-off-by: Jon Hunter <jon-hunter@ti.com>
Signed-off-by: Benoit Cousson <b-cousson@ti.com>

Documentation/devicetree/bindings/arm/omap/counter.txt

+OMAP Counter-32K bindings
+
+Required properties:
+- compatible:	Must be "ti,omap-counter32k" for OMAP controllers
+- reg:		Contains timer register address range (base address and length)
+- ti,hwmods:	Name of the hwmod associated to the counter, which is typically
+		"counter_32k"
+
+Example:
+
+counter32k: counter@4a304000 {
+	compatible = "ti,omap-counter32k";
+	reg = <0x4a304000 0x20>;
+	ti,hwmods = "counter_32k";
+};

arch/arm/boot/dts/omap2420.dtsi

@@ -14,6 +14,12 @@ / {
 	compatible = "ti,omap2420", "ti,omap2";
 
 	ocp {
+		counter32k: counter@48004000 {
+			compatible = "ti,omap-counter32k";
+			reg = <0x48004000 0x20>;
+			ti,hwmods = "counter_32k";
+		};
+
 		omap2420_pmx: pinmux@48000030 {
 			compatible = "ti,omap2420-padconf", "pinctrl-single";
 			reg = <0x48000030 0x0113>;

arch/arm/boot/dts/omap2430.dtsi

@@ -14,6 +14,12 @@ / {
 	compatible = "ti,omap2430", "ti,omap2";
 
 	ocp {
+		counter32k: counter@49020000 {
+			compatible = "ti,omap-counter32k";
+			reg = <0x49020000 0x20>;
+			ti,hwmods = "counter_32k";
+		};
+
 		omap2430_pmx: pinmux@49002030 {
 			compatible = "ti,omap2430-padconf", "pinctrl-single";
 			reg = <0x49002030 0x0154>;

arch/arm/boot/dts/omap3.dtsi

@@ -61,6 +61,12 @@ ocp {
 		ranges;
 		ti,hwmods = "l3_main";
 
+		counter32k: counter@48320000 {
+			compatible = "ti,omap-counter32k";
+			reg = <0x48320000 0x20>;
+			ti,hwmods = "counter_32k";
+		};
+
 		intc: interrupt-controller@48200000 {
 			compatible = "ti,omap2-intc";
 			interrupt-controller;

arch/arm/boot/dts/omap4.dtsi

@@ -95,6 +95,12 @@ ocp {
 		ranges;
 		ti,hwmods = "l3_main_1", "l3_main_2", "l3_main_3";
 
+		counter32k: counter@4a304000 {
+			compatible = "ti,omap-counter32k";
+			reg = <0x4a304000 0x20>;
+			ti,hwmods = "counter_32k";
+		};
+
 		omap4_pmx_core: pinmux@4a100040 {
 			compatible = "ti,omap4-padconf", "pinctrl-single";
 			reg = <0x4a100040 0x0196>;