ASoC: mxs: add device tree support for mxs-saif

Add device tree probe for mxs-saif driver.
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>

Documentation/devicetree/bindings/sound/mxs-saif.txt

+* Freescale MXS Serial Audio Interface (SAIF)
+
+Required properties:
+- compatible: Should be "fsl,<chip>-saif"
+- reg: Should contain registers location and length
+- interrupts: Should contain ERROR and DMA interrupts
+- fsl,saif-dma-channel: APBX DMA channel for the SAIF
+
+Optional properties:
+- fsl,saif-master: phandle to the master SAIF.  It's only required for
+  the slave SAIF.
+
+Note: Each SAIF controller should have an alias correctly numbered
+in "aliases" node.
+
+Example:
+
+aliases {
+	saif0 = &saif0;
+	saif1 = &saif1;
+};
+
+saif0: saif@80042000 {
+	compatible = "fsl,imx28-saif";
+	reg = <0x80042000 2000>;
+	interrupts = <59 80>;
+	fsl,saif-dma-channel = <4>;
+};
+
+saif1: saif@80046000 {
+	compatible = "fsl,imx28-saif";
+	reg = <0x80046000 2000>;
+	interrupts = <58 81>;
+	fsl,saif-dma-channel = <5>;
+	fsl,saif-master = <&saif0>;
+};

sound/soc/mxs/mxs-saif.c

@@ -18,6 +18,8 @@
 
 #include <linux/module.h>
 #include <linux/init.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
 #include <linux/dma-mapping.h>
@@ -622,33 +624,53 @@ static irqreturn_t mxs_saif_irq(int irq, void *dev_id)
 
 static int __devinit mxs_saif_probe(struct platform_device *pdev)
 {
+	struct device_node *np = pdev->dev.of_node;
 	struct resource *iores, *dmares;
 	struct mxs_saif *saif;
 	struct mxs_saif_platform_data *pdata;
 	int ret = 0;
 
-	if (pdev->id >= ARRAY_SIZE(mxs_saif))
+
+	if (!np && pdev->id >= ARRAY_SIZE(mxs_saif))
 		return -EINVAL;
 
 	saif = devm_kzalloc(&pdev->dev, sizeof(*saif), GFP_KERNEL);
 	if (!saif)
 		return -ENOMEM;
 
-	mxs_saif[pdev->id] = saif;
+	if (np) {
+		struct device_node *master;
+		saif->id = of_alias_get_id(np, "saif");
+		if (saif->id < 0)
+			return saif->id;
+		/*
+		 * If there is no "fsl,saif-master" phandle, it's a saif
+		 * master.  Otherwise, it's a slave and its phandle points
+		 * to the master.
+		 */
+		master = of_parse_phandle(np, "fsl,saif-master", 0);
+		if (!master) {
+			saif->master_id = saif->id;
+		} else {
+			saif->master_id = of_alias_get_id(master, "saif");
+			if (saif->master_id < 0)
+				return saif->master_id;
+		}
+	} else {
 		saif->id = pdev->id;
-
 		pdata = pdev->dev.platform_data;
-	if (pdata && !pdata->master_mode) {
+		if (pdata && !pdata->master_mode)
 			saif->master_id = pdata->master_id;
-		if (saif->master_id < 0 ||
-			saif->master_id >= ARRAY_SIZE(mxs_saif) ||
-			saif->master_id == saif->id) {
+		else
+			saif->master_id = saif->id;
+	}
+
+	if (saif->master_id < 0 || saif->master_id >= ARRAY_SIZE(mxs_saif)) {
 		dev_err(&pdev->dev, "get wrong master id\n");
 		return -EINVAL;
 	}
-	} else {
-		saif->master_id = saif->id;
-	}
+
+	mxs_saif[saif->id] = saif;
 
 	saif->clk = clk_get(&pdev->dev, NULL);
 	if (IS_ERR(saif->clk)) {
@@ -669,12 +691,19 @@ static int __devinit mxs_saif_probe(struct platform_device *pdev)
 
 	dmares = platform_get_resource(pdev, IORESOURCE_DMA, 0);
 	if (!dmares) {
-		ret = -ENODEV;
-		dev_err(&pdev->dev, "failed to get dma resource: %d\n",
-			ret);
+		/*
+		 * TODO: This is a temporary solution and should be changed
+		 * to use generic DMA binding later when the helplers get in.
+		 */
+		ret = of_property_read_u32(np, "fsl,saif-dma-channel",
+					   &saif->dma_param.chan_num);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to get dma channel\n");
 			goto failed_get_resource;
 		}
+	} else {
 		saif->dma_param.chan_num = dmares->start;
+	}
 
 	saif->irq = platform_get_irq(pdev, 0);
 	if (saif->irq < 0) {
@@ -735,6 +764,12 @@ static int __devexit mxs_saif_remove(struct platform_device *pdev)
 	return 0;
 }
 
+static const struct of_device_id mxs_saif_dt_ids[] = {
+	{ .compatible = "fsl,imx28-saif", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, mxs_saif_dt_ids);
+
 static struct platform_driver mxs_saif_driver = {
 	.probe = mxs_saif_probe,
 	.remove = __devexit_p(mxs_saif_remove),
@@ -742,6 +777,7 @@ static struct platform_driver mxs_saif_driver = {
 	.driver = {
 		.name = "mxs-saif",
 		.owner = THIS_MODULE,
+		.of_match_table = mxs_saif_dt_ids,
 	},
 };