Re: [PATCH 10/16] media: sun6i-csi: Add support for MC-centric format enumeration

[arash golgol]

Hi Paul,

On Wed, May 27, 2026 at 11:29 AM Paul Kocialkowski <paulk@xxxxxxxxxxx> wrote:
>
> Hi Arash,
>
> On Wed 27 May 26, 09:20, arash golgol wrote:
> > On Mon, May 18, 2026 at 2:00 PM Paul Kocialkowski <paulk@xxxxxxxxxxx> wrote:
> > >
> > > Use the dedicated helper to check possible pixelformats against the
> > > provided mbus code in order to support MC-centric format enumeration.
> > >
> > > Note that multiple pixelformats may be returned for a given mbus code.
> > >
> > > Signed-off-by: Paul Kocialkowski <paulk@xxxxxxxxxxx>
> > > ---
> > >  .../sunxi/sun6i-csi/sun6i_csi_capture.c       | 38 +++++++++++++++++--
> > >  1 file changed, 34 insertions(+), 4 deletions(-)
> > >
> > > diff --git a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c
> > > index a836fa7f081a..409c28621093 100644
> > > --- a/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c
> > > +++ b/drivers/media/platform/sunxi/sun6i-csi/sun6i_csi_capture.c
> > > @@ -773,14 +773,43 @@ static int sun6i_csi_capture_querycap(struct file *file, void *priv,
> > >  static int sun6i_csi_capture_enum_fmt(struct file *file, void *priv,
> > >                                       struct v4l2_fmtdesc *fmtdesc)
> > >  {
> > > +       const struct sun6i_csi_capture_format *capture_format;
> > > +       const struct sun6i_csi_bridge_format *bridge_format;
> > > +       u32 mbus_code = fmtdesc->mbus_code;
> > >         u32 index = fmtdesc->index;
> > > +       unsigned int index_valid = 0;
> > > +       unsigned int i;
> > > +
> > > +       /* Video-node-centric enumeration. */
> > > +       if (!mbus_code) {
> > > +               if (index >= ARRAY_SIZE(sun6i_csi_capture_formats))
> > > +                       return -EINVAL;
> > > +
> > > +               fmtdesc->pixelformat =
> > > +                       sun6i_csi_capture_formats[index].pixelformat;
> > > +               return 0;
> > > +       }
> > >
> > > -       if (index >= ARRAY_SIZE(sun6i_csi_capture_formats))
> > > +       bridge_format = sun6i_csi_bridge_format_find(mbus_code);
> > > +       if (!bridge_format)
> > >                 return -EINVAL;
> > >
> > > -       fmtdesc->pixelformat = sun6i_csi_capture_formats[index].pixelformat;
> > > +       for (i = 0; i < ARRAY_SIZE(sun6i_csi_capture_formats); i++) {
> > > +               capture_format = &sun6i_csi_capture_formats[i];
> > >
> > > -       return 0;
> > > +               if (!sun6i_csi_capture_format_check(capture_format,
> > > +                                                   bridge_format))
> > > +                       continue;
> > > +
> > > +               if (index_valid == index) {
> > > +                       fmtdesc->pixelformat = capture_format->pixelformat;
> > > +                       return 0;
> > > +               }
> > > +
> > > +               index_valid++;
> > > +       }
> > > +
> > > +       return -EINVAL;
> > >  }
> > >
> > >  static int sun6i_csi_capture_enum_framesize(struct file *file, void *fh,
> > > @@ -1076,7 +1105,8 @@ int sun6i_csi_capture_setup(struct sun6i_csi_device *csi_dev)
> > >
> > >         strscpy(video_dev->name, SUN6I_CSI_CAPTURE_NAME,
> > >                 sizeof(video_dev->name));
> > > -       video_dev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING;
> > > +       video_dev->device_caps = V4L2_CAP_VIDEO_CAPTURE | V4L2_CAP_STREAMING |
> > > +                                V4L2_CAP_IO_MC;
> > >         video_dev->vfl_dir = VFL_DIR_RX;
> > >         video_dev->release = video_device_release_empty;
> > >         video_dev->fops = &sun6i_csi_capture_fops;
> > > --
> > > 2.54.0
> > >
> >
> > Tested on a LicheePi Zero Dock (V3s) with the following pipeline:
> >
> > ov7670 -> sun6i-csi-bridge -> sun6i-csi-capture
> >
> > I verified that mbus-code-based format enumeration works correctly
> > from userspace and that the reported capture formats change according
> > to the selected media bus format.
> >
> > I could also successfully start streaming with several of the
> > enumerated capture formats (e.g. YUYV and BA81)
>
> Excellent, thank-you very much for testing this!
>

Happy to help.

> > However, I could not fully validate actual format conversion behavior
> > (e.g. MEDIA_BUS_FMT_YUYV8_2X8 to NV12) because my OV7670 setup
> > currently has non-functional test patterns except for 'shifting-1'
> > mode.
>
> That's fine. I don't think I have tested it recently either.
>
> > Tested-by: Arash Golgol <arash.golgol@xxxxxxxxx>
> >
> > PS:
> >
> > While testing this patch I also noticed that
> > VIDIOC_SUBDEV_ENUM_MBUS_CODE reports duplicate entries for:
> >  - MEDIA_BUS_FMT_UYVY8_2X8
> >  - MEDIA_BUS_FMT_UYVY8_1X16
> > on sun6i-csi-bridge.
>
> I just had a look and you are definitely right, the entries are clearly
> duplicates and at the same time all the relevant formats are included, so they
> are not taking the place of another format that was forgotten.
>
> You're welcome to submit a patch to remove these entries if you'd like,
> or I could do it otherwise.
>

Thanks, I'll send a small patch to remove the duplicate mbus format entries.

> By the way would you be interested in testing the H.264 encoder support for
> V3/V3s once I send a first version for it? I had written initial support for
> it a while ago (did not send it to the list) and now that my work on the V4L2
> stateless uAPI has reached a point of usability I will probably try to update
> my rework of the cedrus driver to use it.
>

Yes, I would definitely be interested in testing the H.264 encoder
support on V3s once you post it. I previously did some experiments
with Cedrus on V3s (bootlin, cedrus/h264-encoding branch).

Looking forward to it!

-- 
Regards,
Arash Golgol