Re: [PATCH v1 1/1 RESEND] media: i2c: mt9m114: Add get_fwnode_pad operation for IFP

[Svyatoslav Ryhel]

ср, 15 лип. 2026 р. о 19:31 Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> пише:
>
> On Wed, Jul 15, 2026 at 07:18:18PM +0300, Svyatoslav Ryhel wrote:
> > вт, 14 лип. 2026 р. о 22:16 Laurent Pinchart пише:
> > > On Thu, Jun 25, 2026 at 11:21:11AM +0300, Svyatoslav Ryhel wrote:
> > > > Currently, the driver's binding exposes only one endpoint, which maps to
> > > > the IFP subdevice's SOURCE pad. This configuration causes failures for
> > > > many devices using this camera because both the DT binding and the
> > > > one-to-one pad mapping logic map the endpoint to the wrong pad.
> > >
> > > Could you please explain what failures this causes ? A brief analysis  of
> > > the code seems to indicate the patch will only make a difference when
> > > the DT node has multiple endpoints, and will prevent links to be created
> > > for any endpoint but the first one. I don't think that's desirable.
> >
> > OF schema documents only a single port with a single endpoint. Since
> > driver has no alternative OF matching logic endpoints patch to media
> > pads one-to-one. IFP has 2 pads, id 0 is sink and id 1 is source. So
> > according to one-to-one match endpoint from the binding co-responds to
> > the sink media pad of IFP, source pad which is usually used to build
> > the video pipe is not represented in the bindings entirely.
>
> But the mt9m114 driver doesn't use 1-to-1 matching, it does not use the
> v4l2_subdev_get_fwnode_pad_1_to_1() function to implement
> .get_fwnode_pad().
>

Correct, hence media framework does not know how to link pads and
starts to do weird stuff.

> > This causes drivers which relay on OF bindings to build their video pipes
> > fail to work with this driver.
>
> Could you provide an example of such a failure ?
>

Tegra VI driver hooks mt9m114 IFP sink pad to sci source and mt9m114
IFP sink pad to csi source. With this patch OF endpoint is strictly
associated with IFP source pad, and nothing else which is desirable
setup IMHO.

> > Sakari suggested this to fix OF
> > matching, so I have implemented it.
> >
> > > > Fix this
> > > > by implementing the get_fwnode_pad operation for the IFP, which correctly
> > > > matches the endpoint to the corresponding IFP pad.
> > > >
> > > > Signed-off-by: Svyatoslav Ryhel <clamor95@xxxxxxxxx>
> > > > ---
> > > >  drivers/media/i2c/mt9m114.c | 44 ++++++++++++++++++++++++++++---------
> > > >  1 file changed, 34 insertions(+), 10 deletions(-)
> > > >
> > > > diff --git a/drivers/media/i2c/mt9m114.c b/drivers/media/i2c/mt9m114.c
> > > > index e395e2d14e97..16c2582551d3 100644
> > > > --- a/drivers/media/i2c/mt9m114.c
> > > > +++ b/drivers/media/i2c/mt9m114.c
> > > > @@ -1020,14 +1020,6 @@ static int mt9m114_stop_streaming(struct mt9m114 *sensor)
> > > >       return ret;
> > > >  }
> > > >
> > > > -/* -----------------------------------------------------------------------------
> > > > - * Common Subdev Operations
> > > > - */
> > > > -
> > > > -static const struct media_entity_operations mt9m114_entity_ops = {
> > > > -     .link_validate = v4l2_subdev_link_validate,
> > > > -};
> > > > -
> > > >  /* -----------------------------------------------------------------------------
> > > >   * Pixel Array Control Operations
> > > >   */
> > > > @@ -1381,6 +1373,10 @@ static const struct v4l2_subdev_internal_ops mt9m114_pa_internal_ops = {
> > > >       .init_state = mt9m114_pa_init_state,
> > > >  };
> > > >
> > > > +static const struct media_entity_operations mt9m114_pa_entity_ops = {
> > > > +     .link_validate = v4l2_subdev_link_validate,
> > > > +};
> > > > +
> > > >  static int mt9m114_pa_init(struct mt9m114 *sensor)
> > > >  {
> > > >       struct v4l2_ctrl_handler *hdl = &sensor->pa.hdl;
> > > > @@ -1403,7 +1399,7 @@ static int mt9m114_pa_init(struct mt9m114 *sensor)
> > > >
> > > >       /* Initialize the media entity. */
> > > >       sd->entity.function = MEDIA_ENT_F_CAM_SENSOR;
> > > > -     sd->entity.ops = &mt9m114_entity_ops;
> > > > +     sd->entity.ops = &mt9m114_pa_entity_ops;
> > > >       pads[0].flags = MEDIA_PAD_FL_SOURCE;
> > > >       ret = media_entity_pads_init(&sd->entity, 1, pads);
> > > >       if (ret < 0)
> > > > @@ -2092,6 +2088,29 @@ static int mt9m114_ifp_registered(struct v4l2_subdev *sd)
> > > >       return 0;
> > > >  }
> > > >
> > > > +/*
> > > > + * The IFP has only one fwnode endpoint, which corresponds to the pad
> > > > + * linked to the PA (PA SINK), while it should be the SOURCE for the
> > > > + * next media device in the pipe.
> > > > + */
> > > > +static int mt9m114_ifp_get_fwnode_pad(struct media_entity *entity,
> > > > +                                   struct fwnode_endpoint *endpoint)
> > > > +{
> > > > +     struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
> > > > +     struct mt9m114 *sensor = ifp_to_mt9m114(sd);
> > > > +     struct fwnode_handle *ifp_port = dev_fwnode(&sensor->client->dev);
> > >
> > > This is not a port fwnode. I'd name the variable just fwnode.
> > >
> >
> > fair
> >
> > > > +     struct fwnode_handle *ifp_ep;
> > > > +     int ret;
> > > > +
> > > > +     ifp_ep = fwnode_graph_get_next_endpoint(ifp_port, NULL);
> > > > +
> > > > +     ret = endpoint->local_fwnode == ifp_ep ? 1 : -ENXIO;
> > > > +
> > > > +     fwnode_handle_put(ifp_ep);
> > > > +
> > > > +     return ret;
> > >
> > > Let's use the cleanup API:
> > >
> > > #include <cleanup.h>
> > >
> > > ...
> > >
> > >         struct v4l2_subdev *sd = media_entity_to_v4l2_subdev(entity);
> > >         struct mt9m114 *sensor = ifp_to_mt9m114(sd);
> > >         struct fwnode_handle *fwnode = dev_fwnode(&sensor->client->dev);
> > >         struct fwnode_handle *ifp_ep __free(fwnode_handle) =
> > >                 fwnode_graph_get_next_endpoint(fwnode, NULL);
> > >
> > >         return endpoint->local_fwnode == ifp_ep ? 1 : -ENXIO;
> > >
> >
> > The code is functionally same. I am fine with any version subsystem
> > maintainer will prefer.
> >

Sakari, should I apply Laurent's changes and resend?

> > > > +}
> > > > +
> > > >  static const struct v4l2_subdev_video_ops mt9m114_ifp_video_ops = {
> > > >       .s_stream = mt9m114_ifp_s_stream,
> > > >  };
> > > > @@ -2119,6 +2138,11 @@ static const struct v4l2_subdev_internal_ops mt9m114_ifp_internal_ops = {
> > > >       .unregistered = mt9m114_ifp_unregistered,
> > > >  };
> > > >
> > > > +static const struct media_entity_operations mt9m114_ifp_entity_ops = {
> > > > +     .link_validate = v4l2_subdev_link_validate,
> > > > +     .get_fwnode_pad = mt9m114_ifp_get_fwnode_pad,
> > > > +};
> > > > +
> > > >  static int mt9m114_ifp_init(struct mt9m114 *sensor)
> > > >  {
> > > >       struct v4l2_subdev *sd = &sensor->ifp.sd;
> > > > @@ -2136,7 +2160,7 @@ static int mt9m114_ifp_init(struct mt9m114 *sensor)
> > > >
> > > >       /* Initialize the media entity. */
> > > >       sd->entity.function = MEDIA_ENT_F_PROC_VIDEO_ISP;
> > > > -     sd->entity.ops = &mt9m114_entity_ops;
> > > > +     sd->entity.ops = &mt9m114_ifp_entity_ops;
> > > >       pads[0].flags = MEDIA_PAD_FL_SINK;
> > > >       pads[1].flags = MEDIA_PAD_FL_SOURCE;
> > > >       ret = media_entity_pads_init(&sd->entity, 2, pads);
>
> --
> Regards,
>
> Laurent Pinchart