dmaengine: dw: enable runtime PM

On runtime PM aware platforms the DMA have to manage its own power state. This
patch enables runtime PM support and applies necessary calls wherever it's
needed.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Tested-by: Scott Ashcroft <scott.ashcroft@talk21.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/dma/dw/core.c

@@ -22,6 +22,7 @@
 #include <linux/mm.h>
 #include <linux/module.h>
 #include <linux/slab.h>
+#include <linux/pm_runtime.h>
 
 #include "../dmaengine.h"
 #include "internal.h"
@@ -1504,6 +1505,9 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	dw->regs = chip->regs;
 	chip->dw = dw;
 
+	pm_runtime_enable(chip->dev);
+	pm_runtime_get_sync(chip->dev);
+
 	dw_params = dma_read_byaddr(chip->regs, DW_PARAMS);
 	autocfg = dw_params >> DW_PARAMS_EN & 0x1;
 
@@ -1667,11 +1671,14 @@ int dw_dma_probe(struct dw_dma_chip *chip, struct dw_dma_platform_data *pdata)
 	dev_info(chip->dev, "DesignWare DMA Controller, %d channels\n",
 		 nr_channels);
 
+	pm_runtime_put_sync_suspend(chip->dev);
+
 	return 0;
 
 err_dma_register:
 	free_irq(chip->irq, dw);
 err_pdata:
+	pm_runtime_put_sync_suspend(chip->dev);
 	return err;
 }
 EXPORT_SYMBOL_GPL(dw_dma_probe);
@@ -1681,6 +1688,8 @@ int dw_dma_remove(struct dw_dma_chip *chip)
 	struct dw_dma		*dw = chip->dw;
 	struct dw_dma_chan	*dwc, *_dwc;
 
+	pm_runtime_get_sync(chip->dev);
+
 	dw_dma_off(dw);
 	dma_async_device_unregister(&dw->dma);
 
@@ -1693,6 +1702,8 @@ int dw_dma_remove(struct dw_dma_chip *chip)
 		channel_clear_bit(dw, CH_EN, dwc->mask);
 	}
 
+	pm_runtime_put_sync_suspend(chip->dev);
+	pm_runtime_disable(chip->dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(dw_dma_remove);