Hi Jacopo,
On Fri, May 17, 2024 at 12:31:43PM +0200, Jacopo Mondi wrote:
> On Thu, May 16, 2024 at 03:25:37PM GMT, Sakari Ailus wrote:
> > Add link_freq field to struct v4l2_mbus_config in order to pass the link
> > frequency to the receiving sub-device.
> >
> > 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 01650aed7c30..ff859a340c5d 100644
> > --- a/drivers/media/v4l2-core/v4l2-common.c
> > +++ b/drivers/media/v4l2-core/v4l2-common.c
> > @@ -506,13 +506,18 @@ 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 = {};
> > 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;
>
> Should we do like what we did with endpoint matching ? (let alone the
> fact we then backtracked on that.. :)
Hmm. What exactly are you suggesting?
>
> WARN to encourage tx drivers to implement get_mbus_config and
> advertise the link freq through it ?
Why? If the value is conveyed by the control, there's no reason to copy it
here, is it?
>
> >
> > - 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);
> > }
> > 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.
> > * @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;
>
> I will retaliate that link_freq has different meaning for serial and
> parallel busses, and it would feel more natural having something like
>
> mipi_csi2.link_freq
> parallel.pixel_clock
>
> or do you think it's an overkill ?
How is the meaning different? The value reflects the frequency on both
buses.
>
> > union {
> > struct v4l2_mbus_config_parallel parallel;
> > struct v4l2_mbus_config_mipi_csi1 mipi_csi1;
--
Kind regards,
Sakari Ailus
