ASoC: Add device tree binding for WM8770

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

Documentation/devicetree/bindings/sound/wm8770.txt

+WM8770 audio CODEC
+
+This device supports SPI.
+
+Required properties:
+
+  - compatible : "wlf,wm8770"
+
+  - reg : the chip select number.
+
+Example:
+
+codec: wm8770@1 {
+	compatible = "wlf,wm8770";
+	reg = <1>;
+};

sound/soc/codecs/wm8770.c

@@ -14,6 +14,7 @@
 #include <linux/moduleparam.h>
 #include <linux/init.h>
 #include <linux/delay.h>
+#include <linux/of_device.h>
 #include <linux/pm.h>
 #include <linux/platform_device.h>
 #include <linux/spi/spi.h>
@@ -684,6 +685,12 @@ static struct snd_soc_codec_driver soc_codec_dev_wm8770 = {
 	.reg_cache_default = wm8770_reg_defs
 };
 
+static const struct of_device_id wm8770_of_match[] = {
+	{ .compatible = "wlf,wm8770", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, wm8770_of_match);
+
 #if defined(CONFIG_SPI_MASTER)
 static int __devinit wm8770_spi_probe(struct spi_device *spi)
 {
@@ -715,6 +722,7 @@ static struct spi_driver wm8770_spi_driver = {
 	.driver = {
 		.name = "wm8770",
 		.owner = THIS_MODULE,
+		.of_match_table = wm8770_of_match,
 	},
 	.probe = wm8770_spi_probe,
 	.remove = __devexit_p(wm8770_spi_remove)