Enable I2S output on 40-pin header

- Use snd-soc-dummy codec and simple-card to get I2S output from SAI1
onto the 40-pin header.

Change-Id: Id85bc34097fe90e8a73fd389e7bbf34f09401b97

arch/arm64/boot/dts/freescale/fsl-imx8mq-phanbell.dts

diff --git a/arch/arm64/boot/dts/freescale/fsl-imx8mq-phanbell.dts b/arch/arm64/boot/dts/freescale/fsl-imx8mq-phanbell.dts
index e67ac41..904d053 100644
--- a/arch/arm64/boot/dts/freescale/fsl-imx8mq-phanbell.dts
+++ b/arch/arm64/boot/dts/freescale/fsl-imx8mq-phanbell.dts
@@ -53,6 +53,26 @@
 		status = "okay";
 	};
 
+	dummy_dai: dummy-dai {
+		compatible = "linux,snd-soc-dummy";
+		#sound-dai-cells = <0>;
+		status = "okay";
+	};
+
+	sound-header {
+		compatible = "simple-audio-card";
+		status = "okay";
+		simple-audio-card,name = "40-pin Header";
+		simple-audio-card,format = "i2s";
+		simple-audio-card,cpu {
+			sound-dai = <&sai1>;
+		};
+		simple-audio-card,codec {
+			#sound-dai-cells = <0>;
+			sound-dai = <&dummy_dai>;
+		};
+	};
+
 	busfreq {
 		status = "disabled";
 	};
@@ -223,10 +243,19 @@
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_sai1>;
 	status = "okay";
+	#sound-dai-cells = <0>;
+	assigned-clocks =
+		<&clk IMX8MQ_CLK_SAI1>;
+	assigned-clock-parents = <&clk IMX8MQ_AUDIO_PLL1_OUT>;
+	assigned-clock-rates = <45158400>;
+
+	clocks = <&clk IMX8MQ_CLK_SAI1_IPG>, <&clk IMX8MQ_CLK_DUMMY>,
+		<&clk IMX8MQ_CLK_SAI1_ROOT>, <&clk IMX8MQ_CLK_DUMMY>,
+		<&clk IMX8MQ_CLK_DUMMY>, <&clk IMX8MQ_AUDIO_PLL1_OUT>,
+		<&clk IMX8MQ_AUDIO_PLL2_OUT>;
+	clock-names = "bus", "mclk0", "mclk1", "mclk2", "mclk3", "pll8k", "pll11k";
 };
 
-		// <&clk IMX8MQ_CLK_SAI2_DIV>;
-	// assigned-clock-rates = <0>, <24576000>;
 &sai2 {
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_sai2>;

sound/soc/soc-utils.c

diff --git a/sound/soc/soc-utils.c b/sound/soc/soc-utils.c
index e30aacb..1a889ac 100644
--- a/sound/soc/soc-utils.c
+++ b/sound/soc/soc-utils.c
@@ -15,6 +15,7 @@
 
 #include <linux/platform_device.h>
 #include <linux/export.h>
+#include <linux/module.h>
 #include <sound/core.h>
 #include <sound/pcm.h>
 #include <sound/pcm_params.h>
@@ -359,9 +360,16 @@ static int snd_soc_dummy_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id soc_dummy_ids[] = {
+	{ .compatible = "linux,snd-soc-dummy", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, soc_dummy_ids);
+
 static struct platform_driver soc_dummy_driver = {
 	.driver = {
 		.name = "snd-soc-dummy",
+		.of_match_table = of_match_ptr(soc_dummy_ids),
 	},
 	.probe = snd_soc_dummy_probe,
 	.remove = snd_soc_dummy_remove,