drm/fsl-dcu: update all registers on flush

Use the UPDATE_MODE READREG bit to initiate a register transfer
on flush. This makes sure that we flush all registers only once
for all planes.
Signed-off-by: Stefan Agner <stefan@agner.ch>

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_crtc.c

@@ -25,8 +25,13 @@
 static void fsl_dcu_drm_crtc_atomic_flush(struct drm_crtc *crtc,
 					  struct drm_crtc_state *old_crtc_state)
 {
+	struct drm_device *dev = crtc->dev;
+	struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
 	struct drm_pending_vblank_event *event = crtc->state->event;
 
+	regmap_write(fsl_dev->regmap,
+		     DCU_UPDATE_MODE, DCU_UPDATE_MODE_READREG);
+
 	if (event) {
 		crtc->state->event = NULL;
 

drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_plane.c

@@ -160,11 +160,6 @@ static void fsl_dcu_drm_plane_atomic_update(struct drm_plane *plane,
 			     DCU_LAYER_POST_SKIP(0) |
 			     DCU_LAYER_PRE_SKIP(0));
 	}
-	regmap_update_bits(fsl_dev->regmap, DCU_DCU_MODE,
-			   DCU_MODE_DCU_MODE_MASK,
-			   DCU_MODE_DCU_MODE(DCU_MODE_NORMAL));
-	regmap_write(fsl_dev->regmap,
-		     DCU_UPDATE_MODE, DCU_UPDATE_MODE_READREG);
 
 	return;
 }