[PATCH 4/4] drm/fsl-dcu: do not update when modifying irq registers

[Stefan Agner]

The IRQ status and mask registers are not "double buffered" according
to the reference manual. Hence, there is no extra transfer/update
write needed when modifying these registers.

Signed-off-by: Stefan Agner <stefan at agner.ch>
---
 drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c | 4 ----
 1 file changed, 4 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 092aaec..4e700bc4 100644
--- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
+++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_drv.c
@@ -59,8 +59,6 @@ static int fsl_dcu_drm_irq_init(struct drm_device *dev)

        regmap_write(fsl_dev->regmap, DCU_INT_STATUS, 0);
        regmap_write(fsl_dev->regmap, DCU_INT_MASK, ~0);
-       regmap_write(fsl_dev->regmap, DCU_UPDATE_MODE,
-                    DCU_UPDATE_MODE_READREG);

        return ret;
 }
@@ -139,8 +137,6 @@ static irqreturn_t fsl_dcu_drm_irq(int irq, void *arg)
                drm_handle_vblank(dev, 0);

        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;
 }
-- 
2.9.3