pwm: tegra: Add device tree support

Add auxdata to instantiate the PWFM controller from a device tree,
include the corresponding nodes in the dtsi files for Tegra 20 and
Tegra 30 and add binding documentation.

Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Thierry Reding <thierry.reding@avionic-design.de>
diff --git a/arch/arm/boot/dts/tegra20.dtsi b/arch/arm/boot/dts/tegra20.dtsi
index c417d67..846af57 100644
--- a/arch/arm/boot/dts/tegra20.dtsi
+++ b/arch/arm/boot/dts/tegra20.dtsi
@@ -123,6 +123,12 @@
 		status = "disable";
 	};
 
+	pwm {
+		compatible = "nvidia,tegra20-pwm";
+		reg = <0x7000a000 0x100>;
+		#pwm-cells = <2>;
+	};
+
 	i2c@7000c000 {
 		compatible = "nvidia,tegra20-i2c";
 		reg = <0x7000c000 0x100>;
diff --git a/arch/arm/boot/dts/tegra30.dtsi b/arch/arm/boot/dts/tegra30.dtsi
index 2dcc09e..f7f428e 100644
--- a/arch/arm/boot/dts/tegra30.dtsi
+++ b/arch/arm/boot/dts/tegra30.dtsi
@@ -117,6 +117,12 @@
 		status = "disable";
 	};
 
+	pwm {
+		compatible = "nvidia,tegra30-pwm", "nvidia,tegra20-pwm";
+		reg = <0x7000a000 0x100>;
+		#pwm-cells = <2>;
+	};
+
 	i2c@7000c000 {
 		compatible =  "nvidia,tegra30-i2c", "nvidia,tegra20-i2c";
 		reg = <0x7000c000 0x100>;