drm/fsl-dcu: remove regmap return value checks

It is not common to do regmap return value checks, especially not
for memory mapped device. We can rule out most error returns since
the conditions are static and we know they are ok (e.g. offset
aligned to register stride). Also without proper error handling
they are not really valuable for the user. Hence remove most of
them.

The check in the interrupt handler is worth keeping since a
volatile register won't be readable in case register caching is
still enabled.

Signed-off-by: Stefan Agner <stefan@agner.ch>

1 files changed, 18 insertions, 36 deletions

diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
index b4e33e3e0250..acb8758b63e2 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -55,20 +55,12 @@ static int fsl_dcu_drm_irq_init(struct drm_device *dev)
 	if (ret < 0)
 		dev_err(dev->dev, "failed to install IRQ handler\n");
 
-	ret = regmap_write(fsl_dev->regmap, DCU_INT_STATUS, 0);
-	if (ret)
-		dev_err(dev->dev, "set DCU_INT_STATUS failed\n");
-	ret = regmap_read(fsl_dev->regmap, DCU_INT_MASK, &value);
-	if (ret)
-		dev_err(dev->dev, "read DCU_INT_MASK failed\n");
+	regmap_write(fsl_dev->regmap, DCU_INT_STATUS, 0);
+	regmap_read(fsl_dev->regmap, DCU_INT_MASK, &value);
 	value &= DCU_INT_MASK_VBLANK;
-	ret = regmap_write(fsl_dev->regmap, DCU_INT_MASK, value);
-	if (ret)
-		dev_err(dev->dev, "set DCU_INT_MASK failed\n");
-	ret = regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
-			   DCU_UPDATE_MODE_READREG);
-	if (ret)
-		dev_err(dev->dev, "set DCU_UPDATE_MODE failed\n");
+	regmap_write(fsl_dev->regmap, DCU_INT_MASK, value);
+	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
+		     DCU_UPDATE_MODE_READREG);
 
 	return ret;
 }
@@ -130,18 +122,17 @@ static irqreturn_t fsl_dcu_drm_irq(int irq, void *arg)
 	int ret;
 
 	ret = regmap_read(fsl_dev->regmap, DCU_INT_STATUS, &int_status);
-	if (ret)
-		dev_err(dev->dev, "set DCU_INT_STATUS failed\n");
+	if (ret) {
+		dev_err(dev->dev, "read DCU_INT_STATUS failed\n");
+		return IRQ_NONE;
+	}
+
 	if (int_status & DCU_INT_STATUS_VBLANK)
 		drm_handle_vblank(dev, 0);
 
-	ret = regmap_write(fsl_dev->regmap, DCU_INT_STATUS, int_status);
-	if (ret)
-		dev_err(dev->dev, "set DCU_INT_STATUS failed\n");
-	ret = regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
-			   DCU_UPDATE_MODE_READREG);
-	if (ret)
-		dev_err(dev->dev, "set DCU_UPDATE_MODE failed\n");
+	regmap_write(fsl_dev->regmap, DCU_INT_STATUS, int_status);
+	regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
+		     DCU_UPDATE_MODE_READREG);
 
 	return IRQ_HANDLED;
 }
@@ -150,15 +141,11 @@ static int fsl_dcu_drm_enable_vblank(struct drm_device *dev, unsigned int pipe)
 {
 	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
 	unsigned int value;
-	int ret;
 
-	ret = regmap_read(fsl_dev->regmap, DCU_INT_MASK, &value);
-	if (ret)
-		dev_err(dev->dev, "read DCU_INT_MASK failed\n");
+	regmap_read(fsl_dev->regmap, DCU_INT_MASK, &value);
 	value &= ~DCU_INT_MASK_VBLANK;
-	ret = regmap_write(fsl_dev->regmap, DCU_INT_MASK, value);
-	if (ret)
-		dev_err(dev->dev, "set DCU_INT_MASK failed\n");
+	regmap_write(fsl_dev->regmap, DCU_INT_MASK, value);
+
 	return 0;
 }
 
@@ -167,15 +154,10 @@ static void fsl_dcu_drm_disable_vblank(struct drm_device *dev,
 {
 	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
 	unsigned int value;
-	int ret;
 
-	ret = regmap_read(fsl_dev->regmap, DCU_INT_MASK, &value);
-	if (ret)
-		dev_err(dev->dev, "read DCU_INT_MASK failed\n");
+	regmap_read(fsl_dev->regmap, DCU_INT_MASK, &value);
 	value |= DCU_INT_MASK_VBLANK;
-	ret = regmap_write(fsl_dev->regmap, DCU_INT_MASK, value);
-	if (ret)
-		dev_err(dev->dev, "set DCU_INT_MASK failed\n");
+	regmap_write(fsl_dev->regmap, DCU_INT_MASK, value);
 }
 
 static const struct file_operations fsl_dcu_drm_fops = {