[RESEND PATCH v3 32/32] media: Documentation: v4l: Document sub-device notifiers

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

Document that sub-device notifiers are now registered using
v4l2_async_subdev_nf_init(). No documentation is changed as it seems that
sub-device notifiers were not documented apart from kernel-doc comments.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 Documentation/driver-api/media/v4l2-subdev.rst | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/Documentation/driver-api/media/v4l2-subdev.rst b/Documentation/driver-api/media/v4l2-subdev.rst
index 83d3d29608136..d62b341642c96 100644
--- a/Documentation/driver-api/media/v4l2-subdev.rst
+++ b/Documentation/driver-api/media/v4l2-subdev.rst
@@ -193,9 +193,7 @@ picked up by bridge drivers.
 Bridge drivers in turn have to register a notifier object. This is
 performed using the :c:func:`v4l2_async_nf_register` call. To
 unregister the notifier the driver has to call
-:c:func:`v4l2_async_nf_unregister`. The former of the two functions
-takes two arguments: a pointer to struct :c:type:`v4l2_device` and a
-pointer to struct :c:type:`v4l2_async_notifier`.
+:c:func:`v4l2_async_nf_unregister`.
 
 Before registering the notifier, bridge drivers must do two things: first, the
 notifier must be initialized using the :c:func:`v4l2_async_nf_init`.
@@ -204,6 +202,12 @@ that the bridge device needs for its operation. Several functions are available
 to add subdevice descriptors to a notifier, depending on the type of device and
 the needs of the driver.
 
+For a sub-device driver to register a notifier, the process is otherwise similar
+to that of a bridge driver, apart from that the notifier is initialised using
+:c:func:`v4l2_async_subdev_nf_init` instead. A sub-device notifier may complete
+only after the V4L2 device becomes available, i.e. there's a path via async
+sub-devices and notifiers to that root notifier.
+
 :c:func:`v4l2_async_nf_add_fwnode`, :c:func:`v4l2_async_nf_add_fwnode_remote`
 :c:and func:`v4l2_async_nf_add_i2c` are for registering their async sub-devices
 :c:with the notifier.
-- 
2.30.2