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[v3,3/3] media: v4l2-async: Log message in case of heterogeneous fwnode match

Message ID 20200621000028.4591-4-laurent.pinchart+renesas@ideasonboard.com
State Accepted
Commit e80cdf0a3843fe570c891cb976feb0c136b19fb7
Headers show
Series [v3,1/3] media: v4l2-async: Accept endpoints and devices for fwnode matching | expand

Commit Message

Laurent Pinchart June 21, 2020, midnight UTC 
When a notifier supplies a device fwnode and a subdev supplies an
endpoint fwnode, incorrect matches may occur if multiple subdevs
correspond to the same device fwnode. This can't be handled
transparently in the framework, and requires the notifier to switch to
endpoint fwnodes. Log a message to notify of this problem. A second
message is added to help accelerating the transition to endpoint
matching.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
---
Changes since v2:

- Use dev_warn() and dev_notice()
- Fix typo
---
 drivers/media/v4l2-core/v4l2-async.c | 24 +++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)
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Patch

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 1599f89c2436..242e0d93e4f0 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -77,6 +77,7 @@  static bool match_fwnode(struct v4l2_async_notifier *notifier,
 	struct fwnode_handle *dev_fwnode;
 	bool asd_fwnode_is_ep;
 	bool sd_fwnode_is_ep;
+	struct device *dev;
 
 	/*
 	 * Both the subdev and the async subdev can provide either an endpoint
@@ -116,7 +117,28 @@  static bool match_fwnode(struct v4l2_async_notifier *notifier,
 
 	fwnode_handle_put(dev_fwnode);
 
-	return dev_fwnode == other_fwnode;
+	if (dev_fwnode != other_fwnode)
+		return false;
+
+	/*
+	 * We have a heterogeneous match. Retrieve the struct device of the side
+	 * that matched on a device fwnode to print its driver name.
+	 */
+	if (sd_fwnode_is_ep)
+		dev = notifier->v4l2_dev ? notifier->v4l2_dev->dev
+		    : notifier->sd->dev;
+	else
+		dev = sd->dev;
+
+	if (dev && dev->driver) {
+		if (sd_fwnode_is_ep)
+			dev_warn(dev, "Driver %s uses device fwnode, incorrect match may occur\n",
+				 dev->driver->name);
+		dev_notice(dev, "Consider updating driver %s to match on endpoints\n",
+			   dev->driver->name);
+	}
+
+	return true;
 }
 
 static bool match_custom(struct v4l2_async_notifier *notifier,