dmaengine: altera-msgdma: add OF support

This driver had no device tree support.

- add compatible field "altr,socfpga-msgdma"
- register dma controller with of_dma_controller_register
Reviewed-by: NStefan Roese <sr@denx.de>
Signed-off-by: NOlivier Dautricourt <olivier.dautricourt@orolia.com>
Link: https://lore.kernel.org/r/7459635ba093d87b6bf12413cf7cfe09f6e3019b.1623251990.git.olivier.dautricourt@orolia.comSigned-off-by: NVinod Koul <vkoul@kernel.org>

drivers/dma/altera-msgdma.c

@@ -19,6 +19,7 @@
 #include <linux/module.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/of_dma.h>
 
 #include "dmaengine.h"
 
@@ -888,6 +889,13 @@ static int msgdma_probe(struct platform_device *pdev)
 	if (ret)
 		goto fail;
 
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 of_dma_xlate_by_chan_id, dma_dev);
+	if (ret == -EINVAL)
+		dev_warn(&pdev->dev, "device was not probed from DT");
+	else if (ret && ret != -ENODEV)
+		goto fail;
+
 	dev_notice(&pdev->dev, "Altera mSGDMA driver probe success\n");
 
 	return 0;
@@ -908,6 +916,8 @@ static int msgdma_remove(struct platform_device *pdev)
 {
 	struct msgdma_device *mdev = platform_get_drvdata(pdev);
 
+	if (pdev->dev.of_node)
+		of_dma_controller_free(pdev->dev.of_node);
 	dma_async_device_unregister(&mdev->dmadev);
 	msgdma_dev_remove(mdev);
 
@@ -916,9 +926,19 @@ static int msgdma_remove(struct platform_device *pdev)
 	return 0;
 }
 
+#ifdef CONFIG_OF
+static const struct of_device_id msgdma_match[] = {
+	{ .compatible = "altr,socfpga-msgdma", },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, msgdma_match);
+#endif
+
 static struct platform_driver msgdma_driver = {
 	.driver = {
 		.name = "altera-msgdma",
+		.of_match_table = of_match_ptr(msgdma_match),
 	},
 	.probe = msgdma_probe,
 	.remove = msgdma_remove,