media: platform: Switch to v4l2_async_notifier_add_subdev

Switch all media platform drivers to call v4l2_async_notifier_add_subdev()
to add asd's to a notifier, in place of referencing the notifier->subdevs[]
array. These drivers also must now call v4l2_async_notifier_init() before
adding asd's to their notifiers.

There may still be cases where a platform driver maintains a list of
asd's that is a duplicate of the notifier asd_list, in which case its
possible the platform driver list can be removed, and can reference the
notifier asd_list instead. One example of where a duplicate list has
been removed in this patch is xilinx-vipp.c. If there are such cases
remaining, those drivers should be optimized to remove the duplicate
platform driver asd lists.

None of the changes to the platform drivers in this patch have been
tested. Verify that the async subdevices needed by the platform are
bound at load time, and that the driver unloads and reloads correctly
with no memory leaking of asd objects.

Suggested-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Steve Longerbeam <slongerbeam@gmail.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

2 files changed, 14 insertions, 10 deletions

diff --git a/drivers/media/platform/rcar-vin/rcar-core.c b/drivers/media/platform/rcar-vin/rcar-core.c
index 9071b88fa2de..a3f135364474 100644
--- a/drivers/media/platform/rcar-vin/rcar-core.c
+++ b/drivers/media/platform/rcar-vin/rcar-core.c
@@ -827,7 +827,7 @@ static int rvin_mc_parse_of_graph(struct rvin_dev *vin)
 
 	mutex_unlock(&vin->group->lock);
 
-	if (!vin->group->notifier.num_subdevs)
+	if (list_empty(&vin->group->notifier.asd_list))
 		return 0;
 
 	vin->group->notifier.ops = &rvin_group_notify_ops;
diff --git a/drivers/media/platform/rcar-vin/rcar-csi2.c b/drivers/media/platform/rcar-vin/rcar-csi2.c
index dc5ae8025832..75ebd9c23813 100644
--- a/drivers/media/platform/rcar-vin/rcar-csi2.c
+++ b/drivers/media/platform/rcar-vin/rcar-csi2.c
@@ -771,21 +771,25 @@ static int rcsi2_parse_dt(struct rcar_csi2 *priv)
 
 	of_node_put(ep);
 
-	priv->notifier.subdevs = devm_kzalloc(priv->dev,
-					      sizeof(*priv->notifier.subdevs),
-					      GFP_KERNEL);
-	if (!priv->notifier.subdevs)
-		return -ENOMEM;
+	v4l2_async_notifier_init(&priv->notifier);
+
+	ret = v4l2_async_notifier_add_subdev(&priv->notifier, &priv->asd);
+	if (ret) {
+		fwnode_handle_put(priv->asd.match.fwnode);
+		return ret;
+	}
 
-	priv->notifier.num_subdevs = 1;
-	priv->notifier.subdevs[0] = &priv->asd;
 	priv->notifier.ops = &rcar_csi2_notify_ops;
 
 	dev_dbg(priv->dev, "Found '%pOF'\n",
 		to_of_node(priv->asd.match.fwnode));
 
-	return v4l2_async_subdev_notifier_register(&priv->subdev,
-						   &priv->notifier);
+	ret = v4l2_async_subdev_notifier_register(&priv->subdev,
+						  &priv->notifier);
+	if (ret)
+		v4l2_async_notifier_cleanup(&priv->notifier);
+
+	return ret;
 }
 
 /* -----------------------------------------------------------------------------