arm64: dts: imx8mq-evk: Enable audio codec wm8524

The main Audio DAC used on the EVK board is wm8524
The EVK provides the MCLK to wm8524.

Digital interface is SAI2 which includes three signals:
SYNC_CLK, BCLK and DACDAT.

This patch sets:
        * SAI2 pinctrl configuration
        * clock hierarchy
        * wm8524 codec

Then uses simple-card machine driver to connect them
into a sound card.
Signed-off-by: Daniel Baluta <daniel.baluta@nxp.com>
Reviewed-by: Fabio Estevam <festevam@gmail.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-evk.dts

@@ -43,6 +43,35 @@ buck2_reg: regulator-buck2 {
 		states = <1000000 0x0
 			  900000 0x1>;
 	};
+
+	wm8524: audio-codec {
+		#sound-dai-cells = <0>;
+		compatible = "wlf,wm8524";
+		wlf,mute-gpios = <&gpio1 8 GPIO_ACTIVE_LOW>;
+	};
+
+	sound-wm8524 {
+		compatible = "simple-audio-card";
+		simple-audio-card,name = "wm8524-audio";
+		simple-audio-card,format = "i2s";
+		simple-audio-card,frame-master = <&cpudai>;
+		simple-audio-card,bitclock-master = <&cpudai>;
+		simple-audio-card,widgets =
+			"Line", "Left Line Out Jack",
+			"Line", "Right Line Out Jack";
+		simple-audio-card,routing =
+			"Left Line Out Jack", "LINEVOUTL",
+			"Right Line Out Jack", "LINEVOUTR";
+
+		cpudai: simple-audio-card,cpu {
+			sound-dai = <&sai2>;
+		};
+
+		link_codec: simple-audio-card,codec {
+			sound-dai = <&wm8524>;
+			clocks = <&clk IMX8MQ_CLK_SAI2_ROOT>;
+		};
+	};
 };
 
 &A53_0 {
@@ -80,6 +109,15 @@ ethphy0: ethernet-phy@0 {
 	};
 };
 
+&sai2 {
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_sai2>;
+	assigned-clocks = <&clk IMX8MQ_CLK_SAI2>;
+	assigned-clock-parents = <&clk IMX8MQ_AUDIO_PLL1_OUT>;
+	assigned-clock-rates = <24576000>;
+	status = "okay";
+};
+
 &i2c1 {
 	clock-frequency = <100000>;
 	pinctrl-names = "default";
@@ -283,6 +321,16 @@ MX8MQ_IOMUXC_SD2_RESET_B_GPIO2_IO19		0x41
 		>;
 	};
 
+	pinctrl_sai2: sai2grp {
+		fsl,pins = <
+			MX8MQ_IOMUXC_SAI2_TXFS_SAI2_TX_SYNC     0xd6
+			MX8MQ_IOMUXC_SAI2_TXC_SAI2_TX_BCLK      0xd6
+			MX8MQ_IOMUXC_SAI2_MCLK_SAI2_MCLK        0xd6
+			MX8MQ_IOMUXC_SAI2_TXD0_SAI2_TX_DATA0    0xd6
+			MX8MQ_IOMUXC_GPIO1_IO08_GPIO1_IO8       0xd6
+		>;
+	};
+
 	pinctrl_uart1: uart1grp {
 		fsl,pins = <
 			MX8MQ_IOMUXC_UART1_RXD_UART1_DCE_RX		0x49