ARM: dts: alt: use demuxer for I2C1

Create a separate bus for HDMI related I2C1 and provide fallback to GPIO.

Based on work for the r8a7790/lager by Wolfram Sang.
Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
[wsa: rebased, fixed aliases, switched to named GPIOs]
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>

arch/arm/boot/dts/r8a7794-alt.dts

@@ -18,7 +18,9 @@ / {
 
 	aliases {
 		serial0 = &scif2;
+		i2c9 = &gpioi2c1;
 		i2c10 = &gpioi2c4;
+		i2c11 = &i2chdmi;
 		i2c12 = &i2cexio4;
 	};
 
@@ -138,16 +140,49 @@ x13_clk: x13-clock {
 		clock-frequency = <148500000>;
 	};
 
+	gpioi2c1: i2c-9 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "i2c-gpio";
+		status = "disabled";
+		scl-gpios = <&gpio4 0 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+		sda-gpios = <&gpio4 1 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+	};
+
 	gpioi2c4: i2c-10 {
 		#address-cells = <1>;
 		#size-cells = <0>;
 		compatible = "i2c-gpio";
 		status = "disabled";
-		sda-gpios = <&gpio4 9 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 		scl-gpios = <&gpio4 8 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
+		sda-gpios = <&gpio4 9 (GPIO_ACTIVE_HIGH | GPIO_OPEN_DRAIN)>;
 		i2c-gpio,delay-us = <5>;
 	};
 
+	/*
+	 * A fallback to GPIO is provided for I2C1.
+	 */
+	i2chdmi: i2c-11 {
+		compatible = "i2c-demux-pinctrl";
+		i2c-parent = <&i2c1>, <&gpioi2c1>;
+		i2c-bus-name = "i2c-hdmi";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		composite-in@20 {
+			compatible = "adi,adv7180";
+			reg = <0x20>;
+			remote = <&vin0>;
+
+			port {
+				adv7180: endpoint {
+					bus-width = <8>;
+					remote-endpoint = <&vin0ep>;
+				};
+			};
+		};
+	};
+
 	/*
 	 * I2C4 is routed to EXIO connector B, pins 73 (SCL) + 74 (SDA).
 	 * A fallback to GPIO is provided.
@@ -324,23 +359,9 @@ &sdhi1 {
 
 &i2c1 {
 	pinctrl-0 = <&i2c1_pins>;
-	pinctrl-names = "default";
+	pinctrl-names = "i2c-hdmi";
 
-	status = "okay";
 	clock-frequency = <400000>;
-
-	composite-in@20 {
-		compatible = "adi,adv7180";
-		reg = <0x20>;
-		remote = <&vin0>;
-
-		port {
-			adv7180: endpoint {
-				bus-width = <8>;
-				remote-endpoint = <&vin0ep>;
-			};
-		};
-	};
 };
 
 &i2c4 {