[PATCH v4 2/2] drivers: dma: altera-msgdma: add OF support

[Olivier Dautricourt <olivier.dautricourt@xxxxxxxxxx>]

This driver had no device tree support.

- add compatible field "altr,msgdma"
- define msgdma_of_xlate, with no argument
- register dma controller with of_dma_controller_register

Signed-off-by: Olivier Dautricourt <olivier.dautricourt@xxxxxxxxxx>
---

Notes:
    Changes in v2:
    	none

    Changes from v2 to v3:
    	Removed CONFIG_OF #ifdef's and use if (IS_ENABLED(CONFIG_OF))
    	only once.

    Changes from v3 to v4
    	Reintroduce #ifdef CONFIG_OF for msgdma_match
    	as it produces a unused variable warning

 drivers/dma/altera-msgdma.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
index 9a841ce5f0c5..7e58385facef 100644
--- a/drivers/dma/altera-msgdma.c
+++ b/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"

@@ -784,6 +785,14 @@ static int request_and_map(struct platform_device *pdev, const char *name,
 	return 0;
 }

+static struct dma_chan *msgdma_of_xlate(struct of_phandle_args *dma_spec,
+					struct of_dma *ofdma)
+{
+	struct msgdma_device *d = ofdma->of_dma_data;
+
+	return dma_get_any_slave_channel(&d->dmadev);
+}
+
 /**
  * msgdma_probe - Driver probe function
  * @pdev: Pointer to the platform_device structure
@@ -888,6 +897,16 @@ static int msgdma_probe(struct platform_device *pdev)
 	if (ret)
 		goto fail;

+	if (IS_ENABLED(CONFIG_OF)) {
+		ret = of_dma_controller_register(pdev->dev.of_node,
+						 msgdma_of_xlate, mdev);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"failed to register dma controller");
+			goto fail;
+		}
+	}
+
 	dev_notice(&pdev->dev, "Altera mSGDMA driver probe success\n");

 	return 0;
@@ -916,9 +935,19 @@ static int msgdma_remove(struct platform_device *pdev)
 	return 0;
 }

+#ifdef CONFIG_OF
+static const struct of_device_id msgdma_match[] = {
+	{ .compatible = "altr,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,
--
2.31.0.rc2