colibri_t20: add i2c support

Add I2C support in order to subsequently allow disabling the PMIC sleep
mode on low supply voltage.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Reviewed-by: Simon Glass <sjg@chromium.org>
Acked-by: Stephen Warren <swarren@nvidia.com>
Signed-off-by: Tom Warren <twarren@nvidia.com>

arch/arm/dts/tegra20-colibri.dts

@@ -11,6 +11,9 @@
 	};
 
 	aliases {
+		i2c0 = "/i2c@7000d000";
+		i2c1 = "/i2c@7000c000";
+		i2c2 = "/i2c@7000c400";
 		usb0 = "/usb@c5008000";
 		usb1 = "/usb@c5000000";
 		usb2 = "/usb@c5004000";
@@ -52,6 +55,31 @@
 		};
 	};
 
+	/*
+	 * GEN1_I2C: I2C_SDA/SCL on SODIMM pin 194/196 (e.g. RTC on carrier
+	 * board)
+	 */
+	i2c@7000c000 {
+		status = "okay";
+		clock-frequency = <100000>;
+	};
+
+	/* GEN2_I2C: unused */
+
+	/* DDC_CLOCK/DATA on X3 pin 15/16 (e.g. display EDID) */
+	i2c@7000c400 {
+		status = "okay";
+		clock-frequency = <100000>;
+	};
+
+	/*
+	 * PWR_I2C: power I2C to PMIC and temperature sensor
+	 */
+	i2c@7000d000 {
+		status = "okay";
+		clock-frequency = <100000>;
+	};
+
 	sdhci@c8000600 {
 		status = "okay";
 		cd-gpios = <&gpio TEGRA_GPIO(C, 7) GPIO_ACTIVE_LOW>;

include/configs/colibri_t20.h

@@ -21,6 +21,10 @@
 
 #define CONFIG_MACH_TYPE		MACH_TYPE_COLIBRI_T20
 
+/* I2C */
+#define CONFIG_SYS_I2C_TEGRA
+#define CONFIG_CMD_I2C
+
 /* SD/MMC support */
 #define CONFIG_MMC
 #define CONFIG_GENERIC_MMC