media: v4l: async: Add some debug prints

Just add some debug prints for V4L2 async sub-device matching process.
These might come useful in figuring out why things don't work as expected.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Tested-by: Philipp Zabel <p.zabel@pengutronix.de> # imx6qp
Tested-by: Niklas Söderlund <niklas.soderlund@ragnatech.se> # rcar + adv746x
Tested-by: Aishwarya Kothari <aishwarya.kothari@toradex.com> # Apalis i.MX6Q with TC358743
Tested-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com> # Renesas RZ/G2L SMARC
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 7831bc8..c578112 100644 (file)
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -77,6 +77,17 @@ static bool match_i2c(struct v4l2_async_notifier *notifier,
 #endif
 }
 
+static struct device *notifier_dev(struct v4l2_async_notifier *notifier)
+{
+       if (notifier->sd)
+               return notifier->sd->dev;
+
+       if (notifier->v4l2_dev)
+               return notifier->v4l2_dev->dev;
+
+       return NULL;
+}
+
 static bool
 match_fwnode_one(struct v4l2_async_notifier *notifier,
                 struct v4l2_subdev *sd, struct fwnode_handle *sd_fwnode,
@@ -88,13 +99,20 @@ match_fwnode_one(struct v4l2_async_notifier *notifier,
        bool sd_fwnode_is_ep;
        struct device *dev;
 
+       dev_dbg(notifier_dev(notifier),
+               "v4l2-async: fwnode match: need %pfw, trying %pfw\n",
+               sd_fwnode, asd->match.fwnode);
+
        /*
         * Both the subdev and the async subdev can provide either an endpoint
         * fwnode or a device fwnode. Start with the simple case of direct
         * fwnode matching.
         */
-       if (sd_fwnode == asd->match.fwnode)
+       if (sd_fwnode == asd->match.fwnode) {
+               dev_dbg(notifier_dev(notifier),
+                       "v4l2-async: direct match found\n");
                return true;
+       }
 
        /*
         * Otherwise, check if the sd fwnode and the asd fwnode refer to an
@@ -107,8 +125,11 @@ match_fwnode_one(struct v4l2_async_notifier *notifier,
        sd_fwnode_is_ep = fwnode_graph_is_endpoint(sd_fwnode);
        asd_fwnode_is_ep = fwnode_graph_is_endpoint(asd->match.fwnode);
 
-       if (sd_fwnode_is_ep == asd_fwnode_is_ep)
+       if (sd_fwnode_is_ep == asd_fwnode_is_ep) {
+               dev_dbg(notifier_dev(notifier),
+                       "v4l2-async: direct match not found\n");
                return false;
+       }
 
        /*
         * The sd and asd fwnodes are of different types. Get the device fwnode
@@ -122,10 +143,17 @@ match_fwnode_one(struct v4l2_async_notifier *notifier,
                other_fwnode = sd_fwnode;
        }
 
+       dev_dbg(notifier_dev(notifier),
+               "v4l2-async: fwnode compat match: need %pfw, trying %pfw\n",
+               dev_fwnode, other_fwnode);
+
        fwnode_handle_put(dev_fwnode);
 
-       if (dev_fwnode != other_fwnode)
+       if (dev_fwnode != other_fwnode) {
+               dev_dbg(notifier_dev(notifier),
+                       "v4l2-async: compat match not found\n");
                return false;
+       }
 
        /*
         * We have a heterogeneous match. Retrieve the struct device of the side
@@ -145,12 +173,18 @@ match_fwnode_one(struct v4l2_async_notifier *notifier,
                           dev->driver->name);
        }
 
+       dev_dbg(notifier_dev(notifier), "v4l2-async: compat match found\n");
+
        return true;
 }
 
 static bool match_fwnode(struct v4l2_async_notifier *notifier,
                         struct v4l2_subdev *sd, struct v4l2_async_subdev *asd)
 {
+       dev_dbg(notifier_dev(notifier),
+               "v4l2-async: matching for notifier %pfw, sd fwnode %pfw\n",
+               dev_fwnode(notifier_dev(notifier)), sd->fwnode);
+
        if (match_fwnode_one(notifier, sd, sd->fwnode, asd))
                return true;
 
@@ -158,6 +192,9 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
        if (IS_ERR_OR_NULL(sd->fwnode->secondary))
                return false;
 
+       dev_dbg(notifier_dev(notifier),
+               "v4l2-async: trying secondary fwnode match\n");
+
        return match_fwnode_one(notifier, sd, sd->fwnode->secondary, asd);
 }
 
@@ -271,22 +308,33 @@ v4l2_async_nf_can_complete(struct v4l2_async_notifier *notifier)
 static int
 v4l2_async_nf_try_complete(struct v4l2_async_notifier *notifier)
 {
+       struct v4l2_async_notifier *__notifier = notifier;
+
        /* Quick check whether there are still more sub-devices here. */
        if (!list_empty(&notifier->waiting))
                return 0;
 
+       if (notifier->sd)
+               dev_dbg(notifier_dev(notifier),
+                       "v4l2-async: trying to complete\n");
+
        /* Check the entire notifier tree; find the root notifier first. */
        while (notifier->parent)
                notifier = notifier->parent;
 
        /* This is root if it has v4l2_dev. */
-       if (!notifier->v4l2_dev)
+       if (!notifier->v4l2_dev) {
+               dev_dbg(notifier_dev(__notifier),
+                       "v4l2-async: V4L2 device not available\n");
                return 0;
+       }
 
        /* Is everything ready? */
        if (!v4l2_async_nf_can_complete(notifier))
                return 0;
 
+       dev_dbg(notifier_dev(__notifier), "v4l2-async: complete\n");
+
        return v4l2_async_nf_call_complete(notifier);
 }
 
@@ -350,6 +398,9 @@ static int v4l2_async_match_notify(struct v4l2_async_notifier *notifier,
        /* Move from the global subdevice list to notifier's done */
        list_move(&sd->async_list, &notifier->done);
 
+       dev_dbg(notifier_dev(notifier), "v4l2-async: %s bound (ret %d)\n",
+               dev_name(sd->dev), ret);
+
        /*
         * See if the sub-device has a notifier. If not, return here.
         */
@@ -378,6 +429,8 @@ v4l2_async_nf_try_all_subdevs(struct v4l2_async_notifier *notifier)
        if (!v4l2_dev)
                return 0;
 
+       dev_dbg(notifier_dev(notifier), "v4l2-async: trying all sub-devices\n");
+
 again:
        list_for_each_entry(sd, &subdev_list, async_list) {
                struct v4l2_async_subdev *asd;
@@ -387,6 +440,9 @@ again:
                if (!asd)
                        continue;
 
+               dev_dbg(notifier_dev(notifier),
+                       "v4l2-async: match found, subdev %s\n", sd->name);
+
                ret = v4l2_async_match_notify(notifier, v4l2_dev, sd, asd);
                if (ret < 0)
                        return ret;
@@ -496,8 +552,7 @@ static int v4l2_async_nf_asd_valid(struct v4l2_async_notifier *notifier,
                                   struct v4l2_async_subdev *asd,
                                   int this_index)
 {
-       struct device *dev =
-               notifier->v4l2_dev ? notifier->v4l2_dev->dev : NULL;
+       struct device *dev = notifier_dev(notifier);
 
        if (!asd)
                return -EINVAL;
@@ -506,12 +561,12 @@ static int v4l2_async_nf_asd_valid(struct v4l2_async_notifier *notifier,
        case V4L2_ASYNC_MATCH_I2C:
        case V4L2_ASYNC_MATCH_FWNODE:
                if (v4l2_async_nf_has_async_subdev(notifier, asd, this_index)) {
-                       dev_dbg(dev, "subdev descriptor already listed in this or other notifiers\n");
+                       dev_dbg(dev, "v4l2-async: subdev descriptor already listed in a notifier\n");
                        return -EEXIST;
                }
                break;
        default:
-               dev_err(dev, "Invalid match type %u on %p\n",
+               dev_err(dev, "v4l2-async: Invalid match type %u on %p\n",
                        asd->match_type, asd);
                return -EINVAL;
        }