This driver had no device tree support.

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

Reviewed-by: Stefan Roese <sr@denx.de>
Signed-off-by: Olivier Dautricourt <redacted>
---

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

    Changes from v4 to v5
        - As per Rob's comments on patch 1/2:
          change compatible field from altr,msgdma to
          altr,socfpga-msgdma.
        - change commit title to fit previous commits naming
        - As per Vinod's comments:
          - use dma_get_slave_channel instead of dma_get_any_slave_channel which
            makes more sense.
          - remove if (IS_ENABLED(CONFIG_OF)) for of_dma_controller_register
            as it is taken care by the core

 drivers/dma/altera-msgdma.c | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/drivers/dma/altera-msgdma.c b/drivers/dma/altera-msgdma.c
index 9a841ce5f0c5..acf0990d73ae 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_slave_channel(&d->dmachan);
+}

+
 /**
  * msgdma_probe - Driver probe function
  * @pdev: Pointer to the platform_device structure

@@ -888,6 +897,13 @@ static int msgdma_probe(struct platform_device *pdev)
 	if (ret)
 		goto fail;

+	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;