DMA-API: staging: use dma_set_coherent_mask()

The correct way for a driver to specify the coherent DMA mask is
not to directly access the field in the struct device, but to use
dma_set_coherent_mask().  Only arch and bus code should access this
member directly.

Convert all direct write accesses to using the correct API.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

drivers/staging/dwc2/platform.c

@@ -100,8 +100,9 @@ static int dwc2_driver_probe(struct platform_device *dev)
 	 */
 	if (!dev->dev.dma_mask)
 		dev->dev.dma_mask = &dev->dev.coherent_dma_mask;
-	if (!dev->dev.coherent_dma_mask)
-		dev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	retval = dma_set_coherent_mask(&dev->dev, DMA_BIT_MASK(32));
+	if (retval)
+		return retval;
 
 	irq = platform_get_irq(dev, 0);
 	if (irq < 0) {

drivers/staging/imx-drm/imx-drm-core.c

@@ -805,6 +805,12 @@ static struct drm_driver imx_drm_driver = {
 
 static int imx_drm_platform_probe(struct platform_device *pdev)
 {
+	int ret;
+
+	ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
+
 	imx_drm_device->dev = &pdev->dev;
 
 	return drm_platform_init(&imx_drm_driver, pdev);
@@ -847,8 +853,6 @@ static int __init imx_drm_init(void)
 		goto err_pdev;
 	}
 
-	imx_drm_pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32),
-
 	ret = platform_driver_register(&imx_drm_pdrv);
 	if (ret)
 		goto err_pdrv;

drivers/staging/imx-drm/ipuv3-crtc.c

@@ -523,7 +523,9 @@ static int ipu_drm_probe(struct platform_device *pdev)
 	if (!pdata)
 		return -EINVAL;
 
-	pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32);
+	ret = dma_set_coherent_mask(&pdev->dev, DMA_BIT_MASK(32));
+	if (ret)
+		return ret;
 
 	ipu_crtc = devm_kzalloc(&pdev->dev, sizeof(*ipu_crtc), GFP_KERNEL);
 	if (!ipu_crtc)