[PATCH v3 3/9] media: rcar-vin: Create a group notifier

[Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>]

As CSI-2 subdevices are shared between several VIN instances, a shared
notifier to collect the CSI-2 async subdevices is required. So far, the
rcar-vin driver used the notifier of the last VIN instance to probe but
with the forth-coming introduction of parallel input subdevices support
in mc-compliant code path, each VIN may register its own notifier if any
parallel subdevice is connected there.

To avoid registering a notifier twice (once for parallel subdev and one
for the CSI-2 subdevs) create a group notifier, shared by all the VIN
instances.

Signed-off-by: Jacopo Mondi <jacopo+renesas@xxxxxxxxxx>
---
 drivers/media/platform/rcar-vin/rcar-core.c | 39 +++++++++++------------------
 drivers/media/platform/rcar-vin/rcar-vin.h  |  7 +++---
 2 files changed, 18 insertions(+), 28 deletions(-)

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index 1aadd90..c6e603f 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -583,7 +583,7 @@ static int rvin_parallel_graph_init(struct rvin_dev *vin)
 
 static int rvin_group_notify_complete(struct v4l2_async_notifier *notifier)
 {
-	struct rvin_dev *vin = notifier_to_vin(notifier);
+	struct rvin_dev *vin = v4l2_dev_to_vin(notifier->v4l2_dev);
 	const struct rvin_group_route *route;
 	unsigned int i;
 	int ret;
@@ -649,7 +649,7 @@ static void rvin_group_notify_unbind(struct v4l2_async_notifier *notifier,
 				     struct v4l2_subdev *subdev,
 				     struct v4l2_async_subdev *asd)
 {
-	struct rvin_dev *vin = notifier_to_vin(notifier);
+	struct rvin_dev *vin = v4l2_dev_to_vin(notifier->v4l2_dev);
 	unsigned int i;
 
 	for (i = 0; i < RCAR_VIN_NUM; i++)
@@ -673,7 +673,7 @@ static int rvin_group_notify_bound(struct v4l2_async_notifier *notifier,
 				   struct v4l2_subdev *subdev,
 				   struct v4l2_async_subdev *asd)
 {
-	struct rvin_dev *vin = notifier_to_vin(notifier);
+	struct rvin_dev *vin = v4l2_dev_to_vin(notifier->v4l2_dev);
 	unsigned int i;
 
 	mutex_lock(&vin->group->lock);
@@ -734,12 +734,6 @@ static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
 
 	mutex_lock(&vin->group->lock);
 
-	/* If there already is a notifier something has gone wrong, bail out. */
-	if (WARN_ON(vin->group->notifier)) {
-		mutex_unlock(&vin->group->lock);
-		return -EINVAL;
-	}
-
 	/* If not all VIN's are registered don't register the notifier. */
 	for (i = 0; i < RCAR_VIN_NUM; i++)
 		if (vin->group->vin[i])
@@ -751,19 +745,16 @@ static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
 	}
 
 	/*
-	 * Have all VIN's look for subdevices. Some subdevices will overlap
-	 * but the parser function can handle it, so each subdevice will
-	 * only be registered once with the notifier.
+	 * Have all VIN's look for CSI-2 subdevices. Some subdevices will
+	 * overlap but the parser function can handle it, so each subdevice
+	 * will only be registered once with the group notifier.
 	 */
-
-	vin->group->notifier = &vin->notifier;
-
 	for (i = 0; i < RCAR_VIN_NUM; i++) {
 		if (!vin->group->vin[i])
 			continue;
 
 		ret = v4l2_async_notifier_parse_fwnode_endpoints_by_port(
-				vin->group->vin[i]->dev, vin->group->notifier,
+				vin->group->vin[i]->dev, &vin->group->notifier,
 				sizeof(struct v4l2_async_subdev), 1,
 				rvin_mc_parse_of_endpoint);
 		if (ret) {
@@ -774,9 +765,12 @@ static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
 
 	mutex_unlock(&vin->group->lock);
 
-	vin->group->notifier->ops = &rvin_group_notify_ops;
+	if (!vin->group->notifier.num_subdevs)
+		return 0;
 
-	ret = v4l2_async_notifier_register(&vin->v4l2_dev, &vin->notifier);
+	vin->group->notifier.ops = &rvin_group_notify_ops;
+	ret = v4l2_async_notifier_register(&vin->v4l2_dev,
+					   &vin->group->notifier);
 	if (ret < 0) {
 		vin_err(vin, "Notifier registration failed\n");
 		return ret;
@@ -1112,15 +1106,10 @@ static int rcar_vin_remove(struct platform_device *pdev)
 	v4l2_async_notifier_unregister(&vin->notifier);
 	v4l2_async_notifier_cleanup(&vin->notifier);
 
-	if (vin->info->use_mc) {
-		mutex_lock(&vin->group->lock);
-		if (vin->group->notifier == &vin->notifier)
-			vin->group->notifier = NULL;
-		mutex_unlock(&vin->group->lock);
+	if (vin->info->use_mc)
 		rvin_group_put(vin);
-	} else {
+	else
 		v4l2_ctrl_handler_free(&vin->ctrl_handler);
-	}
 
 	rvin_dma_unregister(vin);
 
diff --git a/drivers/media/platform/rcar-vin/rcar-vin.h b/drivers/media/platform/rcar-vin/rcar-vin.h
index 755ac3c..7d0ffe08 100644
--- a/drivers/media/platform/rcar-vin/rcar-vin.h
+++ b/drivers/media/platform/rcar-vin/rcar-vin.h
@@ -209,6 +209,8 @@ struct rvin_dev {
 	v4l2_std_id std;
 };
 
+#define v4l2_dev_to_vin(d)	container_of(d, struct rvin_dev, v4l2_dev)
+
 #define vin_to_source(vin)		((vin)->parallel->subdev)
 
 /* Debug */
@@ -225,8 +227,7 @@ struct rvin_dev {
  *
  * @lock:		protects the count, notifier, vin and csi members
  * @count:		number of enabled VIN instances found in DT
- * @notifier:		pointer to the notifier of a VIN which handles the
- *			groups async sub-devices.
+ * @notifier:		group notifier for CSI-2 async subdevices
  * @vin:		VIN instances which are part of the group
  * @csi:		array of pairs of fwnode and subdev pointers
  *			to all CSI-2 subdevices.
@@ -238,7 +239,7 @@ struct rvin_group {
 
 	struct mutex lock;
 	unsigned int count;
-	struct v4l2_async_notifier *notifier;
+	struct v4l2_async_notifier notifier;
 	struct rvin_dev *vin[RCAR_VIN_NUM];
 
 	struct {
-- 
2.7.4