dma: mmp_tdma: move to generic device tree binding

    This patch makes the mmp_tdma controller able to provide DMA
resources in DT environments by providing an dma xlate function to
get the generic DMA device tree helper support. Then DMA clients only
need to call dma_request_slave_channel() for requesting a DMA channel
from dmaengine.
Signed-off-by: Nenghua Cao <nhcao@marvell.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>

drivers/dma/mmp_tdma.c

@@ -22,6 +22,7 @@
 #include <mach/regs-icu.h>
 #include <linux/platform_data/dma-mmp_tdma.h>
 #include <linux/of_device.h>
+#include <linux/of_dma.h>
 
 #include "dmaengine.h"
 
@@ -541,6 +542,45 @@ static int mmp_tdma_chan_init(struct mmp_tdma_device *tdev,
 	return 0;
 }
 
+struct mmp_tdma_filter_param {
+	struct device_node *of_node;
+	unsigned int chan_id;
+};
+
+static bool mmp_tdma_filter_fn(struct dma_chan *chan, void *fn_param)
+{
+	struct mmp_tdma_filter_param *param = fn_param;
+	struct mmp_tdma_chan *tdmac = to_mmp_tdma_chan(chan);
+	struct dma_device *pdma_device = tdmac->chan.device;
+
+	if (pdma_device->dev->of_node != param->of_node)
+		return false;
+
+	if (chan->chan_id != param->chan_id)
+		return false;
+
+	return true;
+}
+
+struct dma_chan *mmp_tdma_xlate(struct of_phandle_args *dma_spec,
+			       struct of_dma *ofdma)
+{
+	struct mmp_tdma_device *tdev = ofdma->of_dma_data;
+	dma_cap_mask_t mask = tdev->device.cap_mask;
+	struct mmp_tdma_filter_param param;
+
+	if (dma_spec->args_count != 1)
+		return NULL;
+
+	param.of_node = ofdma->of_node;
+	param.chan_id = dma_spec->args[0];
+
+	if (param.chan_id >= TDMA_CHANNEL_NUM)
+		return NULL;
+
+	return dma_request_channel(mask, mmp_tdma_filter_fn, &param);
+}
+
 static struct of_device_id mmp_tdma_dt_ids[] = {
 	{ .compatible = "marvell,adma-1.0", .data = (void *)MMP_AUD_TDMA},
 	{ .compatible = "marvell,pxa910-squ", .data = (void *)PXA910_SQU},
@@ -631,6 +671,16 @@ static int mmp_tdma_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	if (pdev->dev.of_node) {
+		ret = of_dma_controller_register(pdev->dev.of_node,
+							mmp_tdma_xlate, tdev);
+		if (ret) {
+			dev_err(tdev->device.dev,
+				"failed to register controller\n");
+			dma_async_device_unregister(&tdev->device);
+		}
+	}
+
 	dev_info(tdev->device.dev, "initialized\n");
 	return 0;
 }