dmaengine: imx-sdma: add device tree probe support

It adds device tree probe support for imx-sdma driver.

Signed-off-by: Shawn Guo <[e-mail]>
Cc: Grant Likely <[e-mail]>
Cc: Vinod Koul <[e-mail]>
Cc: Sascha Hauer <[e-mail]>
Acked-by: Vinod Koul <[e-mail]>

Documentation/devicetree/bindings/dma/fsl-imx-sdma.txt

···
+* Freescale Smart Direct Memory Access (SDMA) Controller for i.MX
+
+Required properties:
+- compatible : Should be "fsl,<chip>-sdma"
+- reg : Should contain SDMA registers location and length
+- interrupts : Should contain SDMA interrupt
+- fsl,sdma-ram-script-name : Should contain the full path of SDMA RAM
+  scripts firmware
+
+Examples:
+
+sdma@83fb0000 {
+	compatible = "fsl,imx51-sdma", "fsl,imx35-sdma";
+	reg = <0x83fb0000 0x4000>;
+	interrupts = <6>;
+	fsl,sdma-ram-script-name = "sdma-imx51.bin";
+};

drivers/dma/imx-sdma.c

···
 #include <linux/slab.h>
 #include <linux/platform_device.h>
 #include <linux/dmaengine.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 #include <asm/irq.h>
 #include <mach/sdma.h>
···
 	}
 };
 MODULE_DEVICE_TABLE(platform, sdma_devtypes);
+
+static const struct of_device_id sdma_dt_ids[] = {
+	{ .compatible = "fsl,imx31-sdma", .data = &sdma_devtypes[IMX31_SDMA], },
+	{ .compatible = "fsl,imx35-sdma", .data = &sdma_devtypes[IMX35_SDMA], },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, sdma_dt_ids);
 
 #define SDMA_H_CONFIG_DSPDMA	(1 << 12) /* indicates if the DSPDMA is used */
 #define SDMA_H_CONFIG_RTD_PINS	(1 << 11) /* indicates if Real-Time Debug pins are enabled */
···
 
 static int __init sdma_probe(struct platform_device *pdev)
 {
+	const struct of_device_id *of_id =
+			of_match_device(sdma_dt_ids, &pdev->dev);
+	struct device_node *np = pdev->dev.of_node;
+	const char *fw_name;
 	int ret;
 	int irq;
 	struct resource *iores;
···
 
 	iores = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	irq = platform_get_irq(pdev, 0);
-	if (!iores || irq < 0 || !pdata) {
+	if (!iores || irq < 0) {
 		ret = -EINVAL;
 		goto err_irq;
 	}
···
 	if (!sdma->script_addrs)
 		goto err_alloc;
 
+	if (of_id)
+		pdev->id_entry = of_id->data;
 	sdma->devtype = pdev->id_entry->driver_data;
 
 	dma_cap_set(DMA_SLAVE, sdma->dma_device.cap_mask);
···
 	if (ret)
 		goto err_init;
 
-	if (pdata->script_addrs)
+	if (pdata && pdata->script_addrs)
 		sdma_add_scripts(sdma, pdata->script_addrs);
 
-	sdma_get_firmware(sdma, pdata->fw_name);
+	if (pdata) {
+		sdma_get_firmware(sdma, pdata->fw_name);
+	} else {
+		/*
+		 * Because that device tree does not encode ROM script address,
+		 * the RAM script in firmware is mandatory for device tree
+		 * probe, otherwise it fails.
+		 */
+		ret = of_property_read_string(np, "fsl,sdma-ram-script-name",
+					      &fw_name);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to get firmware name\n");
+			goto err_init;
+		}
+
+		ret = sdma_get_firmware(sdma, fw_name);
+		if (ret) {
+			dev_err(&pdev->dev, "failed to get firmware\n");
+			goto err_init;
+		}
+	}
 
 	sdma->dma_device.dev = &pdev->dev;
 
···
 static struct platform_driver sdma_driver = {
 	.driver		= {
 		.name	= "imx-sdma",
+		.of_match_table = sdma_dt_ids,
 	},
 	.id_table	= sdma_devtypes,
 	.remove		= __exit_p(sdma_remove),