On Mon, Dec 16, 2024 at 12:05:19PM +0000, Sakari Ailus wrote: > On Mon, Dec 16, 2024 at 01:20:26PM +0200, Laurent Pinchart wrote: > > On Mon, Dec 16, 2024 at 08:07:26AM +0000, Sakari Ailus wrote: > > > On Sun, Dec 15, 2024 at 07:02:40PM +0200, Laurent Pinchart wrote: > > > > On Fri, Dec 13, 2024 at 07:15:55AM +0000, Sakari Ailus wrote: > > > > > On Thu, Dec 12, 2024 at 05:53:53PM +0100, Jacopo Mondi wrote: > > > > > > On Tue, Dec 10, 2024 at 09:59:04AM +0200, Sakari Ailus wrote: > > > > > > > Add the get_mbus_config() as the means for conveying the link frequency > > > > > > > towards the receiver drivers. > > > > > > > > > > > > > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > > > > > > > --- > > > > > > > Documentation/driver-api/media/tx-rx.rst | 4 ++++ > > > > > > > 1 file changed, 4 insertions(+) > > > > > > > > > > > > > > diff --git a/Documentation/driver-api/media/tx-rx.rst b/Documentation/driver-api/media/tx-rx.rst > > > > > > > index dd09484df1d3..1430c330fd52 100644 > > > > > > > --- a/Documentation/driver-api/media/tx-rx.rst > > > > > > > +++ b/Documentation/driver-api/media/tx-rx.rst > > > > > > > @@ -49,6 +49,10 @@ Link frequency > > > > > > > The :ref:`V4L2_CID_LINK_FREQ <v4l2-cid-link-freq>` control is used to tell the > > > > > > > receiver the frequency of the bus (i.e. it is not the same as the symbol rate). > > > > > > > > > > > > > > +On devices where the link frequency isn't configurable, the link_freq field of > > > > > > > +struct v4l2_mbus_config is recommended over controls for conveying the link > > > > > > > +frequency to the downstream driver in the pipeline. > > > > > > > > > > > > When read in its entirety, the paragraphs > > > > > > > > > > > > Link frequency > > > > > > ^^^^^^^^^^^^^^ > > > > > > > > > > > > The :ref:`V4L2_CID_LINK_FREQ <v4l2-cid-link-freq>` control is used to tell the > > > > > > receiver the frequency of the bus (i.e. it is not the same as the symbol rate). > > > > > > > > > > > > On devices where the link frequency isn't configurable, the link_freq field of > > > > > > struct v4l2_mbus_config is recommended over controls for conveying the link > > > > > > frequency. > > > > > > > > > > > > Sounds simpler without the last 7 words. > > > > > > > > > > > > A nit and just tastes maybe > > > > > > > > > > I used: > > > > > > > > > > On devices where the link frequency isn't configurable, using the ``link_freq`` > > > > > field of struct v4l2_mbus_config is recommended over controls. > > > > > > > > Is it a recommendation for the transmitter driver or the receiver driver > > > > ? If it's a recommendation for the transmitter driver, does that mean it > > > > should not implement V4L2_CID_LINK_FREQ in that case ? How about the > > > > need to expose the link frequency to userspace when it's fixed ? > > > > > > For the transmitter. Receivers do not implement get_mbus_config op. I can > > > add a note on this. > > > > They don't implement it, but they call it. I wasn't sure if this > > documentation was from the point of view of the caller or callee. As you > > mentioned separately that it's located in the transmitter section, that > > makes it clearer, but we can also improve the test: > > > > Drivers that have a fixed link frequency should report it through the > > ``.get_mbus_config()`` subdev operation, in the``link_freq`` field of > > struct v4l2_mbus_config, instead of through controls. > > This isn't correct: the link frequency isn't fixed, it's just not > user-configurable. How about: > > Drivers that do not have user-configurable link frequency should report it > through the ``.get_mbus_config()`` subdev pad operation, in the ``link_freq`` > field of struct v4l2_mbus_config, instead of through controls. I'm OK with that. > The ReST seems to be in line with the rest. :-) -- Regards, Laurent Pinchart
