[PATCH v2 20/31] media: v4l: async: Support fwnode endpoint list matching for subdevs

[Sakari Ailus <sakari.ailus@linux.intel.com>]

Support matching V4L2 async sub-devices based on particular fwnode
endpoint. This makes it possible to instantiate multiple V4L2 sub-devices
based on given fwnode endpoints from a single device, based on driver
needs.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 drivers/media/v4l2-core/v4l2-async.c  | 41 +++++++++++++++++++++++++++
 drivers/media/v4l2-core/v4l2-subdev.c | 13 +++++++++
 include/media/v4l2-async.h            | 29 +++++++++++++++++++
 include/media/v4l2-subdev.h           |  8 ++++--
 4 files changed, 89 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 4916f925792b3..8da7722feabcd 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -134,6 +134,30 @@ static bool match_fwnode(struct v4l2_async_notifier *notifier,
 		"v4l2-async: matching for notifier %pfw, sd fwnode %pfw\n",
 		dev_fwnode(notifier_dev(notifier)), sd->fwnode);
 
+	if (!list_empty(&sd->async_subdev_endpoint_list)) {
+		struct v4l2_async_subdev_endpoint *ase;
+
+		dev_dbg(sd->dev,
+			"v4l2-async: endpoint fwnode list available, looking for %pfw\n",
+			match->fwnode);
+
+		list_for_each_entry(ase, &sd->async_subdev_endpoint_list,
+				    async_subdev_endpoint_entry) {
+			bool matched = ase->endpoint == match->fwnode;
+
+			dev_dbg(sd->dev,
+				"v4l2-async: endpoint-endpoint match %sfound with %pfw\n",
+				matched ? "" : "not ", ase->endpoint);
+
+			if (matched)
+				return true;
+		}
+
+		dev_dbg(sd->dev, "async: no endpoint matched\n");
+
+		return false;
+	}
+
 	if (match_fwnode_one(notifier, sd, sd->fwnode, match))
 		return true;
 
@@ -886,6 +910,23 @@ __v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier, int adapter_id,
 }
 EXPORT_SYMBOL_GPL(__v4l2_async_nf_add_i2c);
 
+int v4l2_async_subdev_endpoint_add(struct v4l2_subdev *sd,
+				   struct fwnode_handle *fwnode)
+{
+	struct v4l2_async_subdev_endpoint *ase;
+
+	ase = kmalloc(sizeof(*ase), GFP_KERNEL);
+	if (!ase)
+		return -ENOMEM;
+
+	ase->endpoint = fwnode;
+	list_add(&ase->async_subdev_endpoint_entry,
+		 &sd->async_subdev_endpoint_list);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_subdev_endpoint_add);
+
 struct v4l2_async_connection *
 v4l2_async_connection_unique(struct v4l2_subdev *sd)
 {
diff --git a/drivers/media/v4l2-core/v4l2-subdev.c b/drivers/media/v4l2-core/v4l2-subdev.c
index 2ec179cd12643..217b8019fb9b6 100644
--- a/drivers/media/v4l2-core/v4l2-subdev.c
+++ b/drivers/media/v4l2-core/v4l2-subdev.c
@@ -1467,8 +1467,20 @@ EXPORT_SYMBOL_GPL(__v4l2_subdev_init_finalize);
 
 void v4l2_subdev_cleanup(struct v4l2_subdev *sd)
 {
+	struct v4l2_async_subdev_endpoint *ase, *ase_tmp;
+
 	__v4l2_subdev_state_free(sd->active_state);
 	sd->active_state = NULL;
+
+	if (list_empty(&sd->async_subdev_endpoint_list))
+		return;
+
+	list_for_each_entry_safe(ase, ase_tmp, &sd->async_subdev_endpoint_list,
+				 async_subdev_endpoint_entry) {
+		list_del(&ase->async_subdev_endpoint_entry);
+
+		kfree(ase);
+	}
 }
 EXPORT_SYMBOL_GPL(v4l2_subdev_cleanup);
 
@@ -2182,6 +2194,7 @@ void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
 	sd->dev_priv = NULL;
 	sd->host_priv = NULL;
 	sd->privacy_led = NULL;
+	INIT_LIST_HEAD(&sd->async_subdev_endpoint_list);
 #if defined(CONFIG_MEDIA_CONTROLLER)
 	sd->entity.name = sd->name;
 	sd->entity.obj_type = MEDIA_ENTITY_TYPE_V4L2_SUBDEV;
diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index af02d63fa1ab4..fa64e34c05fc9 100644
--- a/include/media/v4l2-async.h
+++ b/include/media/v4l2-async.h
@@ -142,6 +142,17 @@ struct v4l2_async_notifier {
 	struct list_head notifier_entry;
 };
 
+/**
+ * struct v4l2_async_subdev_endpoint - Entry in sub-device's fwnode list
+ *
+ * @entry: An entry in async_subdev_endpoint_list of &struct v4l2_subdev
+ * @endpoint: Endpoint fwnode agains which to match the sub-device
+ */
+struct v4l2_async_subdev_endpoint {
+	struct list_head async_subdev_endpoint_entry;
+	struct fwnode_handle *endpoint;
+};
+
 /**
  * v4l2_async_debug_init - Initialize debugging tools.
  *
@@ -232,6 +243,24 @@ __v4l2_async_nf_add_i2c(struct v4l2_async_notifier *notifier,
 	((type *)__v4l2_async_nf_add_i2c(notifier, adapter, address, \
 					 sizeof(type)))
 
+/**
+ * v4l2_async_subdev_endpoint_add - Add an endpoint fwnode to async sub-device
+ *				    matching list
+ *
+ * @sd: the sub-device
+ * @fwnode: the endpoint fwnode to match
+ *
+ * Add a fwnode to the async sub-device's matching list. This allows registering
+ * multiple async sub-devices from a single device.
+ *
+ * Note that calling v4l2_subdev_cleanup() as part of the sub-device's cleanup
+ * if endpoints have been added to the sub-device's fwnode matching list.
+ *
+ * Returns an error on failure, 0 on success.
+ */
+int v4l2_async_subdev_endpoint_add(struct v4l2_subdev *sd,
+				   struct fwnode_handle *fwnode);
+
 /**
  * v4l2_async_connection_unique - return a unique &struct v4l2_async_connection
  *				  for a sub-device
diff --git a/include/media/v4l2-subdev.h b/include/media/v4l2-subdev.h
index d2cf9bbae2fb3..27dbc2ef621ff 100644
--- a/include/media/v4l2-subdev.h
+++ b/include/media/v4l2-subdev.h
@@ -1022,6 +1022,8 @@ struct v4l2_subdev_platform_data {
  *	    either dev->of_node->fwnode or dev->fwnode (whichever is non-NULL).
  * @async_list: Links this subdev to a global subdev_entry or @notifier->done
  *	list.
+ * @async_subdev_endpoint_entry: List entry in async_ep_list of
+ *				 &struct v4l2_async_subdev_endpoint
  * @asd: Pointer to respective &struct v4l2_async_connection.
  * @notifier: Pointer to the managing notifier.
  * @subdev_notifier: A sub-device notifier implicitly registered for the sub-
@@ -1065,6 +1067,7 @@ struct v4l2_subdev {
 	struct device *dev;
 	struct fwnode_handle *fwnode;
 	struct list_head async_list;
+	struct list_head async_subdev_endpoint_list;
 	struct v4l2_async_subdev *asd;
 	struct v4l2_async_notifier *notifier;
 	struct v4l2_async_notifier *subdev_notifier;
@@ -1382,8 +1385,9 @@ int __v4l2_subdev_init_finalize(struct v4l2_subdev *sd, const char *name,
  * v4l2_subdev_cleanup() - Releases the resources allocated by the subdevice
  * @sd: The subdevice
  *
- * This function will release the resources allocated in
- * v4l2_subdev_init_finalize.
+ * Clean up a V4L2 async sub-device. Must be called for a sub-device as part of
+ * its release if resources have been associated with it using
+ * v4l2_async_subdev_endpoint_add() or v4l2_subdev_init_finalize().
  */
 void v4l2_subdev_cleanup(struct v4l2_subdev *sd);
 
-- 
2.30.2