[RFC v1.1 2/8] v4l2-async: Add v4l2_async_notifier_add_fwnode_remote_subdev

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

v4l2_async_notifier_add_fwnode_remote_subdev is a convenience function for
parsing information on V4L2 fwnode subdevs.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
since RFC v1:

- Fix documentation for v4l2_async_notifier_add_fwnode_remote_subdev.

 drivers/media/v4l2-core/v4l2-async.c | 23 +++++++++++++++++++++++
 include/media/v4l2-async.h           | 23 +++++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/drivers/media/v4l2-core/v4l2-async.c b/drivers/media/v4l2-core/v4l2-async.c
index 4cb49d5f8c03..9c1937d6ce17 100644
--- a/drivers/media/v4l2-core/v4l2-async.c
+++ b/drivers/media/v4l2-core/v4l2-async.c
@@ -608,6 +608,29 @@ v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
 }
 EXPORT_SYMBOL_GPL(v4l2_async_notifier_add_fwnode_subdev);
 
+int
+v4l2_async_notifier_add_fwnode_remote_subdev(struct v4l2_async_notifier *notif,
+					     struct fwnode_handle *endpoint,
+					     struct v4l2_async_subdev *asd)
+{
+	struct fwnode_handle *remote_ep;
+	int ret;
+
+	remote_ep = fwnode_graph_get_remote_endpoint(endpoint);
+	if (!remote_ep)
+		return -ENOTCONN;
+
+	asd->match_type = V4L2_ASYNC_MATCH_FWNODE;
+	asd->match.fwnode = remote_ep;
+
+	ret = v4l2_async_notifier_add_subdev(notif, asd);
+	if (ret)
+		fwnode_handle_put(remote_ep);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(v4l2_async_notifier_add_fwnode_remote_subdev);
+
 struct v4l2_async_subdev *
 v4l2_async_notifier_add_i2c_subdev(struct v4l2_async_notifier *notifier,
 				   int adapter_id, unsigned short address,
diff --git a/include/media/v4l2-async.h b/include/media/v4l2-async.h
index 1497bda66c3b..b0c50d125ee5 100644
--- a/include/media/v4l2-async.h
+++ b/include/media/v4l2-async.h
@@ -184,6 +184,29 @@ v4l2_async_notifier_add_fwnode_subdev(struct v4l2_async_notifier *notifier,
 				      unsigned int asd_struct_size);
 
 /**
+ * v4l2_async_notifier_add_fwnode_remote_subdev - Allocate and add a fwnode
+ *						  remote async subdev to the
+ *						  notifier's master asd_list.
+ *
+ * @notif: pointer to &struct v4l2_async_notifier
+ * @endpoint: local endpoint the remote sub-device to be matched
+ * @asd: Async sub-device struct allocated by the caller. The &struct
+ *	 v4l2_async_subdev shall be the first member of the driver's async
+ *	 sub-device struct, i.e. both begin at the same memory address.
+ *
+ * Gets the remote endpoint of a given local endpoint, set it up for fwnode
+ * matching and add the async sub-device to the notifier's @asd_list.
+ *
+ * This is just like @v4l2_async_notifier_add_fwnode_subdev, but with the
+ * exception that the fwnode refers to a local endpoint, not the remote one, and
+ * the function relies on the caller to allocate the async sub-device struct.
+ */
+int
+v4l2_async_notifier_add_fwnode_remote_subdev(struct v4l2_async_notifier *notif,
+					     struct fwnode_handle *endpoint,
+					     struct v4l2_async_subdev *asd);
+
+/**
  * v4l2_async_notifier_add_i2c_subdev - Allocate and add an i2c async
  *				subdev to the notifier's master asd_list.
  *
-- 
2.11.0