[media] v4l: vsp1: Add V4L2_CID_ALPHA_COMPONENT control support

The control is used to configure the fixed alpha channel value, when
reading from memory in the RPF or writing to memory in the WPF.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <m.chehab@samsung.com>
diff --git a/drivers/media/platform/vsp1/vsp1_wpf.c b/drivers/media/platform/vsp1/vsp1_wpf.c
index a2ba107..6e05776 100644
--- a/drivers/media/platform/vsp1/vsp1_wpf.c
+++ b/drivers/media/platform/vsp1/vsp1_wpf.c
@@ -39,6 +39,35 @@
 }
 
 /* -----------------------------------------------------------------------------
+ * Controls
+ */
+
+static int wpf_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct vsp1_rwpf *wpf =
+		container_of(ctrl->handler, struct vsp1_rwpf, ctrls);
+	u32 value;
+
+	if (!vsp1_entity_is_streaming(&wpf->entity))
+		return 0;
+
+	switch (ctrl->id) {
+	case V4L2_CID_ALPHA_COMPONENT:
+		value = vsp1_wpf_read(wpf, VI6_WPF_OUTFMT);
+		value &= ~VI6_WPF_OUTFMT_PDV_MASK;
+		value |= ctrl->val << VI6_WPF_OUTFMT_PDV_SHIFT;
+		vsp1_wpf_write(wpf, VI6_WPF_OUTFMT, value);
+		break;
+	}
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops wpf_ctrl_ops = {
+	.s_ctrl = wpf_s_ctrl,
+};
+
+/* -----------------------------------------------------------------------------
  * V4L2 Subdevice Core Operations
  */
 
@@ -51,6 +80,11 @@
 	unsigned int i;
 	u32 srcrpf = 0;
 	u32 outfmt = 0;
+	int ret;
+
+	ret = vsp1_entity_set_streaming(&wpf->entity, enable);
+	if (ret < 0)
+		return ret;
 
 	if (!enable) {
 		vsp1_write(vsp1, VI6_WPF_IRQ_ENB(wpf->entity.index), 0);
@@ -113,7 +147,13 @@
 	    wpf->entity.formats[RWPF_PAD_SOURCE].code)
 		outfmt |= VI6_WPF_OUTFMT_CSC;
 
+	/* Take the control handler lock to ensure that the PDV value won't be
+	 * changed behind our back by a set control operation.
+	 */
+	mutex_lock(wpf->ctrls.lock);
+	outfmt |= vsp1_wpf_read(wpf, VI6_WPF_OUTFMT) & VI6_WPF_OUTFMT_PDV_MASK;
 	vsp1_wpf_write(wpf, VI6_WPF_OUTFMT, outfmt);
+	mutex_unlock(wpf->ctrls.lock);
 
 	vsp1_write(vsp1, VI6_DPR_WPF_FPORCH(wpf->entity.index),
 		   VI6_DPR_WPF_FPORCH_FP_WPFN);
@@ -209,6 +249,20 @@
 
 	vsp1_entity_init_formats(subdev, NULL);
 
+	/* Initialize the control handler. */
+	v4l2_ctrl_handler_init(&wpf->ctrls, 1);
+	v4l2_ctrl_new_std(&wpf->ctrls, &wpf_ctrl_ops, V4L2_CID_ALPHA_COMPONENT,
+			  0, 255, 1, 255);
+
+	wpf->entity.subdev.ctrl_handler = &wpf->ctrls;
+
+	if (wpf->ctrls.error) {
+		dev_err(vsp1->dev, "wpf%u: failed to initialize controls\n",
+			index);
+		ret = wpf->ctrls.error;
+		goto error;
+	}
+
 	/* Initialize the video device. */
 	video = &wpf->video;