Em Mon, 13 Dec 2021 23:28:44 +0000 Daniel Scally <djrscally@xxxxxxxxx> escreveu: > Hello all > > At present there's no means in the kernel of describing the supporting > relationship between subdevices that work together to form an effective single > unit - the type example in this case being a camera sensor and its > corresponding vcm. To attempt to solve that, this series adds a new type of > media link called MEDIA_LNK_FL_ANCILLARY_LINK, which connects two instances of > struct media_entity. > > The mechanism of connection I have modelled as a notifier and async subdev, > which seemed the best route since sensor drivers already typically will call > v4l2_async_register_subdev_sensor() on probe, and that function already looks > for a reference to a firmware node with the reference named "lens-focus". To > avoid boilerplate in the sensor drivers, I added some new functions in > v4l2-async that are called in v4l2_async_match_notify() to create the ancillary > links - checking the entity.function of both notifier and subdev to make sure > that's appropriate. I haven't gone further than that yet, but I suspect we could > cut down on code elsewhere by, for example, also creating pad-to-pad links in > the same place. > > Thoughts and comments very welcome The idea of ancillary link sounds interesting. I did a quick look at the series. Laurent already did some good points during his review. Besides that, one thing it is missing, though, is an implementation on a driver. At least vimc should gain an implementation at this series, in order to allow media developers to test and see how the graph will be after the patch series. Regards, Mauro > > Dan > > Daniel Scally (5): > media: media.h: Add new media link type > media: entity: Add link_type() helper > media: entity: Skip non-data links in graph iteration > media: entity: Add support for ancillary links > media: v4l2-async: Create links during v4l2_async_match_notify() > > drivers/media/mc/mc-entity.c | 56 ++++++++++++++++++++++++++-- > drivers/media/v4l2-core/v4l2-async.c | 51 +++++++++++++++++++++++++ > include/media/media-entity.h | 29 ++++++++++++++ > include/uapi/linux/media.h | 1 + > 4 files changed, 134 insertions(+), 3 deletions(-) > Thanks, Mauro
