ARM: dts: stm32: Add bindings for audio on AV96

Fill in the bindings for HDMI audio on AV96, this permits audio playback
via attached HDMI device if such device supports it.
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Alexandre Torgue <alexandre.torgue@st.com>
Cc: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com>
Cc: Patrice Chotard <patrice.chotard@st.com>
Cc: Patrick Delaunay <patrick.delaunay@st.com>
Cc: linux-stm32@st-md-mailman.stormreply.com
To: linux-arm-kernel@lists.infradead.org
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/boot/dts/stm32mp157a-avenger96.dts

@@ -98,6 +98,13 @@ sd_switch: regulator-sd_switch {
 			 <2900000 0x0>;
 	};
 
+	sound {
+		compatible = "audio-graph-card";
+		label = "STM32MP1-AV96-HDMI";
+		dais = <&sai2a_port>;
+		status = "okay";
+	};
+
 	/* Enpirion EP3A8LQI U2 on the DHCOR */
 	vdd_io: regulator-buck-io {
 		compatible = "regulator-fixed";
@@ -361,6 +368,13 @@ adv7513_out: endpoint {
 					remote-endpoint = <&hdmi_con>;
 				};
 			};
+
+			port@2 {
+				reg = <2>;
+				adv7513_i2s0: endpoint {
+					remote-endpoint = <&sai2a_endpoint>;
+				};
+			};
 		};
 	};
 
@@ -425,6 +439,31 @@ &rtc {
 	status = "okay";
 };
 
+&sai2 {
+	clocks = <&rcc SAI2>, <&rcc PLL3_Q>, <&rcc PLL3_R>;
+	pinctrl-names = "default", "sleep";
+	pinctrl-0 = <&sai2a_pins_c>;
+	pinctrl-1 = <&sai2a_sleep_pins_c>;
+	clock-names = "pclk", "x8k", "x11k";
+	status = "okay";
+
+	sai2a: audio-controller@4400b004 {
+		#clock-cells = <0>;
+		dma-names = "tx";
+		clocks = <&rcc SAI2_K>;
+		clock-names = "sai_ck";
+		status = "okay";
+
+		sai2a_port: port {
+			sai2a_endpoint: endpoint {
+				remote-endpoint = <&adv7513_i2s0>;
+				format = "i2s";
+				mclk-fs = <256>;
+			};
+		};
+	};
+};
+
 &sdmmc1 {
 	pinctrl-names = "default", "opendrain", "sleep";
 	pinctrl-0 = <&sdmmc1_b4_pins_a &sdmmc1_dir_pins_b>;