dmaengine: dw_dmac: Enhance device tree support

dw_dmac driver already supports device tree but it used to have its platform
data passed the non-DT way.

This patch does following changes:
- pass platform data via DT, non-DT way still takes precedence if both are used.
- create generic filter routine
- Earlier slave information was made available by slave specific filter routines
  in chan->private field. Now, this information would be passed from within dmac
  DT node. Slave drivers would now be required to pass bus_id (a string) as
  parameter to this generic filter(), which would be compared against the slave
  data passed from DT, by the generic filter routine.
- Update binding document

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
[Fixed __devinit usage]
Signed-off-by: Vinod Koul <vinod.koul@linux.intel.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/dma/dw_dmac_regs.h b/drivers/dma/dw_dmac_regs.h
index 88965597b7d0..88a069f66b89 100644
--- a/drivers/dma/dw_dmac_regs.h
+++ b/drivers/dma/dw_dmac_regs.h
@@ -239,6 +239,10 @@ struct dw_dma {
 	struct tasklet_struct	tasklet;
 	struct clk		*clk;
 
+	/* slave information */
+	struct dw_dma_slave	*sd;
+	unsigned int		sd_count;
+
 	u8			all_chan_mask;
 
 	/* hardware configuration */