ARM: tegra: Fix I2C bus frequencies on Apalis/Colibri

Use a faster speed of 400 kbit/s for regular I2C busses.

Use a slower speed of 10 kbit/s for DDC/EDID to improve reliability.

Use a slower speed of 100 kbit/s for power I2C to be within specs of
the LM95245 temperature sensor.

While at it further annotate I2C pin usage.

Signed-off-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

arch/arm/boot/dts/tegra124-apalis-eval.dts

@@ -105,7 +105,7 @@
 	 */
 	i2c@7000c000 {
 		status = "okay";
-		clock-frequency = <100000>;
+		clock-frequency = <400000>;
 
 		pcie-switch@58 {
 			compatible = "plx,pex8605";
@@ -124,7 +124,6 @@
 	 */
 	hdmi_ddc: i2c@7000c400 {
 		status = "okay";
-		clock-frequency = <100000>;
 	};
 
 	/*
@@ -133,7 +132,7 @@
 	 */
 	i2c@7000c500 {
 		status = "okay";
-		clock-frequency = <100000>;
+		clock-frequency = <400000>;
 	};
 
 	/* I2C4 (DDC): unused */

arch/arm/boot/dts/tegra124-apalis.dtsi

@@ -1579,7 +1579,7 @@
 	};
 
 	hdmi_ddc: i2c@7000c400 {
-		clock-frequency = <100000>;
+		clock-frequency = <10000>;
 	};
 
 	/* PWR_I2C: power I2C to audio codec, PMIC and temperature sensor */

arch/arm/boot/dts/tegra20-colibri-512.dtsi

@@ -213,21 +213,27 @@
 			GPIO_ACTIVE_HIGH>;
 	};
 
+	/*
+	 * GEN1_I2C: I2C_SDA/SCL on SODIMM pin 194/196 (e.g. RTC on carrier
+	 * board)
+	 */
 	i2c@7000c000 {
 		clock-frequency = <400000>;
 	};
 
+	/* DDC_SCL/SDA on X3 pin 15/16 (e.g. display EDID) */
 	i2c_ddc: i2c@7000c400 {
-		clock-frequency = <100000>;
+		clock-frequency = <10000>;
 	};
 
-	i2c@7000c500 {
-		clock-frequency = <400000>;
-	};
+	/* GEN2_I2C: unused */
 
+	/* CAM/GEN3_I2C: used as EXT_IO1/2 GPIOs on SODIMM pin 133/127 */
+
+	/* PWR_I2C: power I2C to PMIC and temperature sensor (On-module) */
 	i2c@7000d000 {
 		status = "okay";
-		clock-frequency = <400000>;
+		clock-frequency = <100000>;
 
 		pmic: tps6586x@34 {
 			compatible = "ti,tps6586x";

arch/arm/boot/dts/tegra30-apalis-eval.dts

@@ -79,7 +79,7 @@
 	 */
 	i2c@7000c000 {
 		status = "okay";
-		clock-frequency = <100000>;
+		clock-frequency = <400000>;
 
 		pcie-switch@58 {
 			compatible = "plx,pex8605";

arch/arm/boot/dts/tegra30-apalis.dtsi

@@ -437,7 +437,7 @@
 	};
 
 	hdmiddc: i2c@7000c700 {
-		clock-frequency = <100000>;
+		clock-frequency = <10000>;
 	};
 
 	/*

arch/arm/boot/dts/tegra30-colibri-eval-v3.dts

@@ -56,7 +56,7 @@
 	 */
 	i2c@7000c000 {
 		status = "okay";
-		clock-frequency = <100000>;
+		clock-frequency = <400000>;
 
 		/* M41T0M6 real time clock on carrier board */
 		rtc@68 {

arch/arm/boot/dts/tegra30-colibri.dtsi

@@ -215,7 +215,7 @@
 	};
 
 	hdmiddc: i2c@7000c700 {
-		clock-frequency = <100000>;
+		clock-frequency = <10000>;
 	};
 
 	/*