ASoC: pxa: pxa-ssp: add DT bindings

The pxa ssp DAI acts as a user of a pxa ssp port, and needs an
appropriate 'port' phandle in DT to reference the upstream.
Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

Documentation/devicetree/bindings/sound/mrvl,pxa-ssp.txt

+Marvell PXA SSP CPU DAI bindings
+
+Required properties:
+
+	compatible	Must be "mrvl,pxa-ssp-dai"
+	port		A phandle reference to a PXA ssp upstream device
+
+Example:
+
+	/* upstream device */
+
+	ssp0: ssp@41000000 {
+		compatible = "mrvl,pxa3xx-ssp";
+		reg = <0x41000000 0x40>;
+		interrupts = <24>;
+		clock-names = "pxa27x-ssp.0";
+		dmas = <&dma 13
+			&dma 14>;
+		dma-names = "rx", "tx";
+	};
+
+	/* DAI as user */
+
+	ssp_dai0: ssp_dai@0 {
+		compatible = "mrvl,pxa-ssp-dai";
+		port = <&ssp0>;
+	};
+

sound/soc/pxa/pxa-ssp.c

@@ -21,6 +21,7 @@
 #include <linux/clk.h>
 #include <linux/io.h>
 #include <linux/pxa2xx_ssp.h>
+#include <linux/of.h>
 
 #include <asm/irq.h>
 
@@ -719,6 +720,7 @@ static int pxa_ssp_trigger(struct snd_pcm_substream *substream, int cmd,
 
 static int pxa_ssp_probe(struct snd_soc_dai *dai)
 {
+	struct device *dev = dai->dev;
 	struct ssp_priv *priv;
 	int ret;
 
@@ -726,11 +728,27 @@ static int pxa_ssp_probe(struct snd_soc_dai *dai)
 	if (!priv)
 		return -ENOMEM;
 
+	if (dev->of_node) {
+		struct device_node *ssp_handle;
+
+		ssp_handle = of_parse_phandle(dev->of_node, "port", 0);
+		if (!ssp_handle) {
+			dev_err(dev, "unable to get 'port' phandle\n");
+			return -ENODEV;
+		}
+
+		priv->ssp = pxa_ssp_request_of(ssp_handle, "SoC audio");
+		if (priv->ssp == NULL) {
+			ret = -ENODEV;
+			goto err_priv;
+		}
+	} else {
 		priv->ssp = pxa_ssp_request(dai->id + 1, "SoC audio");
 		if (priv->ssp == NULL) {
 			ret = -ENODEV;
 			goto err_priv;
 		}
+	}
 
 	priv->dai_fmt = (unsigned int) -1;
 	snd_soc_dai_set_drvdata(dai, priv);
@@ -798,6 +816,12 @@ static const struct snd_soc_component_driver pxa_ssp_component = {
 	.name		= "pxa-ssp",
 };
 
+#ifdef CONFIG_OF
+static const struct of_device_id pxa_ssp_of_ids[] = {
+	{ .compatible = "mrvl,pxa-ssp-dai" },
+};
+#endif
+
 static int asoc_ssp_probe(struct platform_device *pdev)
 {
 	return snd_soc_register_component(&pdev->dev, &pxa_ssp_component,
@@ -814,6 +838,7 @@ static struct platform_driver asoc_ssp_driver = {
 	.driver = {
 		.name = "pxa-ssp-dai",
 		.owner = THIS_MODULE,
+		.of_match_table = of_match_ptr(pxa_ssp_of_ids),
 	},
 
 	.probe = asoc_ssp_probe,