arm64: dts: renesas: cat874: Add HDMI audio

The CAT874 board pushes sound via I2S over SSI0 into the
TDA19988BET chip.
This commit wires things up so that we can get sound out of
the HDMI interface.
Signed-off-by: NFabrizio Castro <fabrizio.castro@bp.renesas.com>
Signed-off-by: NSimon Horman <horms+renesas@verge.net.au>

arch/arm64/boot/dts/renesas/r8a774c0-cat874.dts

@@ -8,6 +8,7 @@
 /dts-v1/;
 #include "r8a774c0.dtsi"
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/display/tda998x.h>
 
 / {
 	model = "Silicon Linux RZ/G2E 96board platform (CAT874)";
@@ -63,6 +64,23 @@
 		reg = <0x0 0x48000000 0x0 0x78000000>;
 	};
 
+	sound: sound {
+		compatible = "simple-audio-card";
+
+		simple-audio-card,name = "CAT874 HDMI sound";
+		simple-audio-card,format = "i2s";
+		simple-audio-card,bitclock-master = <&sndcpu>;
+		simple-audio-card,frame-master = <&sndcpu>;
+
+		sndcpu: simple-audio-card,cpu {
+			sound-dai = <&rcar_sound>;
+		};
+
+		sndcodec: simple-audio-card,codec {
+			sound-dai = <&tda19988>;
+		};
+	};
+
 	vcc_sdhi0: regulator-vcc-sdhi0 {
 		compatible = "regulator-fixed";
 
@@ -93,6 +111,10 @@
 	};
 };
 
+&audio_clk_a {
+	clock-frequency = <22579200>;
+};
+
 &du {
 	pinctrl-0 = <&du_pins>;
 	pinctrl-names = "default";
@@ -133,6 +155,10 @@
 
 		video-ports = <0x234501>;
 
+		#sound-dai-cells = <0>;
+		audio-ports = <TDA998x_I2S 0x03>;
+		clocks = <&rcar_sound 1>;
+
 		ports {
 			#address-cells = <1>;
 			#size-cells = <0>;
@@ -216,6 +242,36 @@
 		function = "sdhi0";
 		power-source = <1800>;
 	};
+
+	sound_pins: sound {
+		groups = "ssi01239_ctrl", "ssi0_data";
+		function = "ssi";
+	};
+
+	sound_clk_pins: sound_clk {
+		groups = "audio_clkout1_a";
+		function = "audio_clk";
+	};
+};
+
+&rcar_sound {
+	pinctrl-0 = <&sound_pins &sound_clk_pins>;
+	pinctrl-names = "default";
+
+	/* Single DAI */
+	#sound-dai-cells = <0>;
+
+	/* audio_clkout0/1/2/3 */
+	#clock-cells = <1>;
+	clock-frequency = <11289600>;
+
+	status = "okay";
+
+	rcar_sound,dai {
+		dai0 {
+			playback = <&ssi0 &src0 &dvc0>;
+		};
+	};
 };
 
 &rwdt {