[PATCH v1 1/3] dmaengine: sf-pdma: Support of_dma_controller_register()

[shravan chippa <shravan.chippa@microchip.com>]

From: Shravan Chippa <shravan.chippa@microchip.com>

Update sf-pdma driver to adopt generic DMA device tree bindings.
It calls of_dma_controller_register() with sf-pdma specific
of_dma_xlate to get the generic DMA device tree helper support
and the DMA clients can look up the sf-pdma controller using
standard APIs.

Signed-off-by: Shravan Chippa <shravan.chippa@microchip.com>
---
 drivers/dma/sf-pdma/sf-pdma.c | 41 +++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c
index d1c6956af452..c7558c9f9ac3 100644
--- a/drivers/dma/sf-pdma/sf-pdma.c
+++ b/drivers/dma/sf-pdma/sf-pdma.c
@@ -20,6 +20,7 @@
 #include <linux/mod_devicetable.h>
 #include <linux/dma-mapping.h>
 #include <linux/of.h>
+#include <linux/of_dma.h>
 #include <linux/slab.h>
 
 #include "sf-pdma.h"
@@ -490,6 +491,33 @@ static void sf_pdma_setup_chans(struct sf_pdma *pdma)
 	}
 }
 
+static struct dma_chan *sf_pdma_of_xlate(struct of_phandle_args *dma_spec,
+					 struct of_dma *ofdma)
+{
+	struct sf_pdma *pdma = ofdma->of_dma_data;
+	struct device *dev = pdma->dma_dev.dev;
+	struct sf_pdma_chan  *chan;
+	struct dma_chan *c;
+	u32 channel_id;
+
+	if (dma_spec->args_count != 1) {
+		dev_err(dev, "Bad number of cells\n");
+		return NULL;
+	}
+
+	channel_id = dma_spec->args[0];
+
+	chan = &pdma->chans[channel_id];
+
+	c = dma_get_slave_channel(&chan->vchan.chan);
+	if (!c) {
+		dev_err(dev, "No more channels available\n");
+		return NULL;
+	}
+
+	return c;
+}
+
 static int sf_pdma_probe(struct platform_device *pdev)
 {
 	struct sf_pdma *pdma;
@@ -563,7 +591,20 @@ static int sf_pdma_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ret = of_dma_controller_register(pdev->dev.of_node,
+					 sf_pdma_of_xlate, pdma);
+	if (ret < 0) {
+		dev_err(&pdev->dev,
+			"Can't register SiFive Platform OF_DMA. (%d)\n", ret);
+		goto err_unregister;
+	}
+
 	return 0;
+
+err_unregister:
+	dma_async_device_unregister(&pdma->dma_dev);
+
+	return ret;
 }
 
 static int sf_pdma_remove(struct platform_device *pdev)
-- 
2.34.1