[PATCH v3 2/4] rcar-vin: Add control for alpha component

[Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>]

In preparation to adding support for RGB pixel formats with an alpha
component add a control to allow the user to control which alpha value
should be used.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@xxxxxxxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
---
 drivers/media/platform/rcar-vin/rcar-core.c | 53 ++++++++++++++++++++-
 drivers/media/platform/rcar-vin/rcar-dma.c  |  5 ++
 drivers/media/platform/rcar-vin/rcar-vin.h  |  5 ++
 3 files changed, 61 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index 64f9cf790445d14e..ee6e6cb39c749675 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -389,6 +389,28 @@ static void rvin_group_put(struct rvin_dev *vin)
 	kref_put(&group->refcount, rvin_group_release);
 }
 
+/* -----------------------------------------------------------------------------
+ * Controls
+ */
+
+static int rvin_s_ctrl(struct v4l2_ctrl *ctrl)
+{
+	struct rvin_dev *vin =
+		container_of(ctrl->handler, struct rvin_dev, ctrl_handler);
+
+	switch (ctrl->id) {
+	case V4L2_CID_ALPHA_COMPONENT:
+		rvin_set_alpha(vin, ctrl->val);
+		break;
+	}
+
+	return 0;
+}
+
+static const struct v4l2_ctrl_ops rvin_ctrl_ops = {
+	.s_ctrl = rvin_s_ctrl,
+};
+
 /* -----------------------------------------------------------------------------
  * Async notifier
  */
@@ -478,6 +500,15 @@ static int rvin_parallel_subdevice_attach(struct rvin_dev *vin,
 	if (ret < 0)
 		return ret;
 
+	v4l2_ctrl_new_std(&vin->ctrl_handler, &rvin_ctrl_ops,
+			  V4L2_CID_ALPHA_COMPONENT, 0, 255, 1, 255);
+
+	if (vin->ctrl_handler.error) {
+		ret = vin->ctrl_handler.error;
+		v4l2_ctrl_handler_free(&vin->ctrl_handler);
+		return ret;
+	}
+
 	ret = v4l2_ctrl_add_handler(&vin->ctrl_handler, subdev->ctrl_handler,
 				    NULL, true);
 	if (ret < 0) {
@@ -870,6 +901,21 @@ static int rvin_mc_init(struct rvin_dev *vin)
 	if (ret)
 		rvin_group_put(vin);
 
+	ret = v4l2_ctrl_handler_init(&vin->ctrl_handler, 1);
+	if (ret < 0)
+		return ret;
+
+	v4l2_ctrl_new_std(&vin->ctrl_handler, &rvin_ctrl_ops,
+			  V4L2_CID_ALPHA_COMPONENT, 0, 255, 1, 255);
+
+	if (vin->ctrl_handler.error) {
+		ret = vin->ctrl_handler.error;
+		v4l2_ctrl_handler_free(&vin->ctrl_handler);
+		return ret;
+	}
+
+	vin->vdev.ctrl_handler = &vin->ctrl_handler;
+
 	return ret;
 }
 
@@ -1245,6 +1291,7 @@ static int rcar_vin_probe(struct platform_device *pdev)
 
 	vin->dev = &pdev->dev;
 	vin->info = of_device_get_match_data(&pdev->dev);
+	vin->alpha = 0xff;
 
 	/*
 	 * Special care is needed on r8a7795 ES1.x since it
@@ -1288,6 +1335,8 @@ static int rcar_vin_probe(struct platform_device *pdev)
 	return 0;
 
 error_group_unregister:
+	v4l2_ctrl_handler_free(&vin->ctrl_handler);
+
 	if (vin->info->use_mc) {
 		mutex_lock(&vin->group->lock);
 		if (&vin->v4l2_dev == vin->group->notifier.v4l2_dev) {
@@ -1323,10 +1372,10 @@ static int rcar_vin_remove(struct platform_device *pdev)
 		}
 		mutex_unlock(&vin->group->lock);
 		rvin_group_put(vin);
-	} else {
-		v4l2_ctrl_handler_free(&vin->ctrl_handler);
 	}
 
+	v4l2_ctrl_handler_free(&vin->ctrl_handler);
+
 	rvin_dma_unregister(vin);
 
 	return 0;
diff --git a/drivers/media/platform/rcar-vin/rcar-dma.c b/drivers/media/platform/rcar-vin/rcar-dma.c
index 2d146ecf93d66ad5..4e991cce5fb56a90 100644
--- a/drivers/media/platform/rcar-vin/rcar-dma.c
+++ b/drivers/media/platform/rcar-vin/rcar-dma.c
@@ -1343,3 +1343,8 @@ int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel)
 
 	return 0;
 }
+
+void rvin_set_alpha(struct rvin_dev *vin, unsigned int alpha)
+{
+	vin->alpha = alpha;
+}
diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
index 0b13b34d03e3dce4..365dfde06ec25add 100644
--- a/drivers/media/platform/rcar-vin/rcar-vin.h
+++ b/drivers/media/platform/rcar-vin/rcar-vin.h
@@ -178,6 +178,8 @@ struct rvin_info {
  * @compose:		active composing
  * @source:		active size of the video source
  * @std:		active video standard of the video source
+ *
+ * @alpha:		Alpha component to fill in for supported pixel formats
  */
 struct rvin_dev {
 	struct device *dev;
@@ -215,6 +217,8 @@ struct rvin_dev {
 	struct v4l2_rect compose;
 	struct v4l2_rect source;
 	v4l2_std_id std;
+
+	unsigned int alpha;
 };
 
 #define vin_to_source(vin)		((vin)->parallel->subdev)
@@ -266,5 +270,6 @@ const struct rvin_video_format *rvin_format_from_pixel(u32 pixelformat);
 void rvin_crop_scale_comp(struct rvin_dev *vin);
 
 int rvin_set_channel_routing(struct rvin_dev *vin, u8 chsel);
+void rvin_set_alpha(struct rvin_dev *vin, unsigned int alpha);
 
 #endif
-- 
2.21.0