Hi Laurent, On Tue, May 30, 2023 at 09:18:20AM +0300, Laurent Pinchart wrote: > Hi Sakari, > > Thank you for the patch. > > On Thu, May 25, 2023 at 12:16:15PM +0300, Sakari Ailus wrote: > > 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@xxxxxxxxxxxxxxx> > > --- > > 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. > > This is correct, but I doubt anyone who doesn't have an in-depth > knowledge of the v4l2-async framework will be able to understand it. For > instance, the concept of "root notifier" isn't explained anywhere. And > the v4l2_async_subdev_nf_register() function isn't mentioned. That's because the function no longer exists. :-) > > The v4l2-async documentation needs a rewrite. It would benefit from improvements, yes. I can add patches for this if you prefer. > > > + > > :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. > -- Regards, Sakari Ailus
