[PATCH] dw_dmac: absence of pdata isn't critical when autocfg is set

[Andy Shevchenko <andriy.shevchenko@linux.intel.com>]

The patch allows to probe the device when platform data is absent and hardware
auto configuration is enabled. In that case the default platform data is used
where the channel allocation order is set to ascending, channel priority is set
to ascending, and private property is set to true.

Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
 drivers/dma/dw_dmac.c |   15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c
index 2c8096d..0ec5c84 100644
--- a/drivers/dma/dw_dmac.c
+++ b/drivers/dma/dw_dmac.c
@@ -1585,6 +1585,12 @@ dw_dma_parse_dt(struct platform_device *pdev)
 }
 #endif
 
+static struct dw_dma_platform_data dw_dma_pdata = {
+	.is_private = true,
+	.chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
+	.chan_priority = CHAN_PRIORITY_ASCENDING,
+};
+
 static int __devinit dw_probe(struct platform_device *pdev)
 {
 	struct dw_dma_platform_data *pdata;
@@ -1604,9 +1610,6 @@ static int __devinit dw_probe(struct platform_device *pdev)
 	if (!pdata)
 		pdata = dw_dma_parse_dt(pdev);
 
-	if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
-		return -EINVAL;
-
 	io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!io)
 		return -EINVAL;
@@ -1622,6 +1625,12 @@ static int __devinit dw_probe(struct platform_device *pdev)
 	dw_params = dma_read_byaddr(regs, DW_PARAMS);
 	autocfg = dw_params >> DW_PARAMS_EN & 0x1;
 
+	if (!pdata && autocfg)
+		pdata = &dw_dma_pdata;
+
+	if (!pdata || pdata->nr_channels > DW_DMA_MAX_NR_CHANNELS)
+		return -EINVAL;
+
 	if (autocfg)
 		nr_channels = (dw_params >> DW_PARAMS_NR_CHAN & 0x7) + 1;
 	else
-- 
1.7.10.4