ASoC: ak4642: add Device Tree support

Support for loading the ak4642 codec module via devicetree.
Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

Documentation/devicetree/bindings/sound/ak4642.txt

+AK4642 I2C transmitter
+
+This device supports I2C mode only.
+
+Required properties:
+
+  - compatible : "asahi-kasei,ak4642" or "asahi-kasei,ak4643" or "asahi-kasei,ak4648"
+  - reg : The chip select number on the I2C bus
+
+Example:
+
+&i2c {
+	ak4648: ak4648@0x12 {
+		compatible = "asahi-kasei,ak4642";
+		reg = <0x12>;
+	};
+};

sound/soc/codecs/ak4642.c

@@ -26,6 +26,7 @@
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/slab.h>
+#include <linux/of_device.h>
 #include <linux/module.h>
 #include <sound/soc.h>
 #include <sound/initval.h>
@@ -513,12 +514,31 @@ static struct snd_soc_codec_driver soc_codec_dev_ak4648 = {
 };
 
 #if defined(CONFIG_I2C) || defined(CONFIG_I2C_MODULE)
+static struct of_device_id ak4642_of_match[];
 static int ak4642_i2c_probe(struct i2c_client *i2c,
 			    const struct i2c_device_id *id)
 {
+	struct device_node *np = i2c->dev.of_node;
+	const struct snd_soc_codec_driver *driver;
+
+	driver = NULL;
+	if (np) {
+		const struct of_device_id *of_id;
+
+		of_id = of_match_device(ak4642_of_match, &i2c->dev);
+		if (of_id)
+			driver = of_id->data;
+	} else {
+		driver = (struct snd_soc_codec_driver *)id->driver_data;
+	}
+
+	if (!driver) {
+		dev_err(&i2c->dev, "no driver\n");
+		return -EINVAL;
+	}
+
 	return snd_soc_register_codec(&i2c->dev,
-				(struct snd_soc_codec_driver *)id->driver_data,
-				&ak4642_dai, 1);
+				      driver, &ak4642_dai, 1);
 }
 
 static int ak4642_i2c_remove(struct i2c_client *client)
@@ -527,6 +547,14 @@ static int ak4642_i2c_remove(struct i2c_client *client)
 	return 0;
 }
 
+static struct of_device_id ak4642_of_match[] __devinitconst = {
+	{ .compatible = "asahi-kasei,ak4642",	.data = &soc_codec_dev_ak4642},
+	{ .compatible = "asahi-kasei,ak4643",	.data = &soc_codec_dev_ak4642},
+	{ .compatible = "asahi-kasei,ak4648",	.data = &soc_codec_dev_ak4648},
+	{},
+};
+MODULE_DEVICE_TABLE(of, ak4642_of_match);
+
 static const struct i2c_device_id ak4642_i2c_id[] = {
 	{ "ak4642", (kernel_ulong_t)&soc_codec_dev_ak4642 },
 	{ "ak4643", (kernel_ulong_t)&soc_codec_dev_ak4642 },
@@ -539,6 +567,7 @@ static struct i2c_driver ak4642_i2c_driver = {
 	.driver = {
 		.name = "ak4642-codec",
 		.owner = THIS_MODULE,
+		.of_match_table = ak4642_of_match,
 	},
 	.probe		= ak4642_i2c_probe,
 	.remove		= ak4642_i2c_remove,