Hi Sakari, Thank you for the patch. On Tue, Dec 10, 2024 at 09:59:03AM +0200, Sakari Ailus wrote: > Add link_freq field to struct v4l2_mbus_config in order to pass the link > frequency to the receiving sub-device. The documentation of v4l2_get_link_freq() should be expanded to explain the new mode of operation. It should document which of the supported methods are recommended for new drivers. > > Signed-off-by: Sakari Ailus <sakari.ailus@xxxxxxxxxxxxxxx> > --- > drivers/media/v4l2-core/v4l2-common.c | 11 ++++++++--- > include/media/v4l2-mediabus.h | 2 ++ > 2 files changed, 10 insertions(+), 3 deletions(-) > > diff --git a/drivers/media/v4l2-core/v4l2-common.c b/drivers/media/v4l2-core/v4l2-common.c > index 9fe74c7e064f..88fbd5608f00 100644 > --- a/drivers/media/v4l2-core/v4l2-common.c > +++ b/drivers/media/v4l2-core/v4l2-common.c > @@ -508,13 +508,18 @@ EXPORT_SYMBOL_GPL(__v4l2_get_link_freq_ctrl); > s64 __v4l2_get_link_freq_pad(struct media_pad *pad, unsigned int mul, > unsigned int div) > { > + struct v4l2_mbus_config mbus_config = {}; Isn't mbus_config fully populated by the .get_mbus_config() operation ? That should be documented in the .get_mbus_config() operation documentation. > struct v4l2_subdev *sd; > + int ret; > > sd = media_entity_to_v4l2_subdev(pad->entity); > - if (!sd) > - return -ENODEV; > + ret = v4l2_subdev_call(sd, pad, get_mbus_config, pad->index, > + &mbus_config); > + if (ret < 0 && ret != -ENOIOCTLCMD) > + return ret; > > - return __v4l2_get_link_freq_ctrl(sd->ctrl_handler, mul, div); > + return mbus_config.link_freq ?: > + __v4l2_get_link_freq_ctrl(sd->ctrl_handler, mul, div); if (mbus_config.link_freq) return mbus_config.link_freq; return __v4l2_get_link_freq_ctrl(sd->ctrl_handler, mul, div); I wonder if we should also add a message in case link_freq is 0, to get drivers to convert to reporting the link frequency through .get_mbus_config() if they already implement the operation. > } > EXPORT_SYMBOL_GPL(__v4l2_get_link_freq_pad); > #endif /* CONFIG_MEDIA_CONTROLLER */ > diff --git a/include/media/v4l2-mediabus.h b/include/media/v4l2-mediabus.h > index 5bce6e423e94..cc5f776dc662 100644 > --- a/include/media/v4l2-mediabus.h > +++ b/include/media/v4l2-mediabus.h > @@ -148,6 +148,7 @@ enum v4l2_mbus_type { > /** > * struct v4l2_mbus_config - media bus configuration > * @type: interface type > + * @link_freq: The link frequency. See also V4L2_CID_LINK_FREQ control. Not a candidate for this series, but I'd like to simplify drivers by implementing the LINK_FREQ control automatically. > * @bus: bus configuration data structure > * @bus.parallel: embedded &struct v4l2_mbus_config_parallel. > * Used if the bus is parallel or BT.656. > @@ -162,6 +163,7 @@ enum v4l2_mbus_type { > */ > struct v4l2_mbus_config { > enum v4l2_mbus_type type; > + u64 link_freq; > union { > struct v4l2_mbus_config_parallel parallel; > struct v4l2_mbus_config_mipi_csi1 mipi_csi1; -- Regards, Laurent Pinchart