[media] v4l: vsp1: bru: Don't program background color in control set handler

The datasheet clearly states that all but a few registers can't be
modified when the device is running. Programming the background color
in the control set handler is thus prohibited. Program it when starting
the module instead.

This requires storing the background color value internally as the
module can be started from the frame completion interrupt handler, and
accessing control values requires taking a mutex.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>

drivers/media/platform/vsp1/vsp1_bru.c

@@ -42,13 +42,9 @@ static int bru_s_ctrl(struct v4l2_ctrl *ctrl)
 	struct vsp1_bru *bru =
 		container_of(ctrl->handler, struct vsp1_bru, ctrls);
 
-	if (!vsp1_entity_is_streaming(&bru->entity))
-		return 0;
-
 	switch (ctrl->id) {
 	case V4L2_CID_BG_COLOR:
-		vsp1_bru_write(bru, VI6_BRU_VIRRPF_COL, ctrl->val |
-			       (0xff << VI6_BRU_VIRRPF_COL_A_SHIFT));
+		bru->bgcolor = ctrl->val;
 		break;
 	}
 
@@ -95,12 +91,17 @@ static int bru_s_stream(struct v4l2_subdev *subdev, int enable)
 		       flags & V4L2_PIX_FMT_FLAG_PREMUL_ALPHA ?
 		       0 : VI6_BRU_INCTRL_NRM);
 
-	/* Set the background position to cover the whole output image. */
+	/* Set the background position to cover the whole output image and
+	 * configure its color.
+	 */
 	vsp1_bru_write(bru, VI6_BRU_VIRRPF_SIZE,
 		       (format->width << VI6_BRU_VIRRPF_SIZE_HSIZE_SHIFT) |
 		       (format->height << VI6_BRU_VIRRPF_SIZE_VSIZE_SHIFT));
 	vsp1_bru_write(bru, VI6_BRU_VIRRPF_LOC, 0);
 
+	vsp1_bru_write(bru, VI6_BRU_VIRRPF_COL, bru->bgcolor |
+		       (0xff << VI6_BRU_VIRRPF_COL_A_SHIFT));
+
 	/* Route BRU input 1 as SRC input to the ROP unit and configure the ROP
 	 * unit with a NOP operation to make BRU input 1 available as the
 	 * Blend/ROP unit B SRC input.
@@ -438,6 +439,8 @@ struct vsp1_bru *vsp1_bru_create(struct vsp1_device *vsp1)
 	v4l2_ctrl_new_std(&bru->ctrls, &bru_ctrl_ops, V4L2_CID_BG_COLOR,
 			  0, 0xffffff, 1, 0);
 
+	bru->bgcolor = 0;
+
 	bru->entity.subdev.ctrl_handler = &bru->ctrls;
 
 	if (bru->ctrls.error) {

drivers/media/platform/vsp1/vsp1_bru.h

@@ -33,6 +33,8 @@ struct vsp1_bru {
 		struct vsp1_rwpf *rpf;
 		struct v4l2_rect compose;
 	} inputs[VSP1_MAX_RPF];
+
+	u32 bgcolor;
 };
 
 static inline struct vsp1_bru *to_bru(struct v4l2_subdev *subdev)