[media] v4l: vsp1: rwpf: Don't program alpha value 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 alpha value in
the control set handler is thus prohibited. Program it when starting the
module instead.

This requires storing the alpha 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>

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/media/platform/vsp1/vsp1_rwpf.c b/drivers/media/platform/vsp1/vsp1_rwpf.c
index 9688c219b30e..ba50386db35c 100644
--- a/drivers/media/platform/vsp1/vsp1_rwpf.c
+++ b/drivers/media/platform/vsp1/vsp1_rwpf.c
@@ -230,3 +230,38 @@ int vsp1_rwpf_set_selection(struct v4l2_subdev *subdev,
 
 	return 0;
 }
+
+/* -----------------------------------------------------------------------------
+ * Controls
+ */
+
+static int vsp1_rwpf_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct vsp1_rwpf *rwpf =
+		container_of(ctrl->handler, struct vsp1_rwpf, ctrls);
+
+	switch (ctrl->id) {
+	case V4L2_CID_ALPHA_COMPONENT:
+		rwpf->alpha = ctrl->val;
+		break;
+	}
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops vsp1_rwpf_ctrl_ops = {
+	.s_ctrl = vsp1_rwpf_s_ctrl,
+};
+
+int vsp1_rwpf_init_ctrls(struct vsp1_rwpf *rwpf)
+{
+	rwpf->alpha = 255;
+
+	v4l2_ctrl_handler_init(&rwpf->ctrls, 1);
+	v4l2_ctrl_new_std(&rwpf->ctrls, &vsp1_rwpf_ctrl_ops,
+			  V4L2_CID_ALPHA_COMPONENT, 0, 255, 1, 255);
+
+	rwpf->entity.subdev.ctrl_handler = &rwpf->ctrls;
+
+	return rwpf->ctrls.error;
+}