tegra: fdt: i2c: Add extra I2C bindings for U-Boot

Add U-Boot's peripheral clock information to the Tegra20 device tree file.

Signed-off-by: Simon Glass <sjg@chromium.org>
Acked-by: Stephen Warren <swarren@wwwdotorg.org>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/dts/tegra20.dtsi

@@ -34,6 +34,8 @@
 		compatible = "nvidia,tegra20-i2c";
 		reg = <0x7000C000 0x100>;
 		interrupts = < 70 >;
+		/* PERIPH_ID_I2C1, PLL_P_OUT3 */
+		clocks = <&tegra_car 12>, <&tegra_car 124>;
 	};
 
 	i2c@7000c400 {
@@ -42,6 +44,8 @@
 		compatible = "nvidia,tegra20-i2c";
 		reg = <0x7000C400 0x100>;
 		interrupts = < 116 >;
+		/* PERIPH_ID_I2C2, PLL_P_OUT3 */
+		clocks = <&tegra_car 54>, <&tegra_car 124>;
 	};
 
 	i2c@7000c500 {
@@ -50,14 +54,18 @@
 		compatible = "nvidia,tegra20-i2c";
 		reg = <0x7000C500 0x100>;
 		interrupts = < 124 >;
+		/* PERIPH_ID_I2C3, PLL_P_OUT3 */
+		clocks = <&tegra_car 67>, <&tegra_car 124>;
 	};
 
 	i2c@7000d000 {
 		#address-cells = <1>;
 		#size-cells = <0>;
-		compatible = "nvidia,tegra20-i2c";
+		compatible = "nvidia,tegra20-i2c-dvc";
 		reg = <0x7000D000 0x200>;
 		interrupts = < 85 >;
+		/* PERIPH_ID_DVC_I2C, PLL_P_OUT3 */
+		clocks = <&tegra_car 47>, <&tegra_car 124>;
 	};
 
 	i2s@70002800 {

doc/device-tree-bindings/i2c/tegra20-i2c.txt

@@ -0,0 +1,23 @@
+(Placeholder note while we locate the kernel Tegra20 bindings)
+
+Added in U-Boot:
+
+Required properties:
+ - clocks : Two clocks must be given, each as a phandle to the Tegra's
+            CAR node and the clock number as a parameter:
+     - the I2C clock to use for the peripheral
+     - the pll_p_out3 clock, which can be used for fast operation. This
+          does not change and is the same for all I2C nodes.
+
+Example:
+(TODO: merge with existing example):
+
+	i2c@7000c400 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "nvidia,tegra20-i2c";
+		reg = <0x7000C400 0x100>;
+		interrupts = < 116 >;
+		/* PERIPH_ID_I2C2, PLL_P_OUT3 */
+		clocks = <&tegra_car 54>, <&tegra_car 124>;
+	};