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References: <20220607134405.166704-1-ribalda@chromium.org> <20220607134405.166704-2-ribalda@chromium.org>
 <Yp+hF+HcZUIqC/Pm@pendragon.ideasonboard.com>
In-Reply-To: <Yp+hF+HcZUIqC/Pm@pendragon.ideasonboard.com>
From:   Ricardo Ribalda <ribalda@chromium.org>
Date:   Tue, 7 Jun 2022 23:50:15 +0200
Message-ID: <CANiDSCt-2RWQqGi9z=fm26NZWodr0yJHrtdJeePcKsKjxsVO4Q@mail.gmail.com>
Subject: Re: [PATCH v3 1/7] media: uvcvideo: Add missing value for power_line_frequency
To:     Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc:     Mauro Carvalho Chehab <mchehab@kernel.org>,
        linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
        Tomasz Figa <tfiga@chromium.org>,
        Sergey Senozhatsky <senozhatsky@chromium.org>,
        Yunke Cao <yunkec@google.com>
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Hi Laurent

On Tue, 7 Jun 2022 at 21:04, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> Hi Ricardo,
>
> Thank you for the patch.

Thanks for your review :)

>
> On Tue, Jun 07, 2022 at 03:43:58PM +0200, Ricardo Ribalda wrote:
> > UVC 1.5 class defines 4 values for this control on:
> > 4.2.2.3.6 Power Line Frequency Control
> >
> > Add the missing value when the uvc version is 1.5.
> >
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> >  drivers/media/usb/uvc/uvc_ctrl.c | 67 ++++++++++++++++++++++++++------
> >  1 file changed, 55 insertions(+), 12 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index 0e78233fc8a0..f9d4ac81e62f 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -362,12 +362,19 @@ static const u32 uvc_control_classes[] = {
> >       V4L2_CID_USER_CLASS,
> >  };
> >
> > -static const struct uvc_menu_info power_line_frequency_controls[] = {
> > +static const struct uvc_menu_info power_line_frequency_controls_uvc11[] = {
> >       { 0, "Disabled" },
> >       { 1, "50 Hz" },
> >       { 2, "60 Hz" },
> >  };
>
> Let's drop this, and ...
>
> >
> > +static const struct uvc_menu_info power_line_frequency_controls_uvc15[] = {
>
> ... rename this to power_line_frequency_controls, and ...
>
> > +     { 0, "Disabled" },
> > +     { 1, "50 Hz" },
> > +     { 2, "60 Hz" },
> > +     { 3, "Auto" },
> > +};
> > +
> >  static const struct uvc_menu_info exposure_auto_controls[] = {
> >       { 2, "Auto Mode" },
> >       { 1, "Manual Mode" },
> > @@ -504,17 +511,6 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> >               .v4l2_type      = V4L2_CTRL_TYPE_INTEGER,
> >               .data_type      = UVC_CTRL_DATA_TYPE_UNSIGNED,
> >       },
> > -     {
> > -             .id             = V4L2_CID_POWER_LINE_FREQUENCY,
> > -             .entity         = UVC_GUID_UVC_PROCESSING,
> > -             .selector       = UVC_PU_POWER_LINE_FREQUENCY_CONTROL,
> > -             .size           = 2,
> > -             .offset         = 0,
> > -             .v4l2_type      = V4L2_CTRL_TYPE_MENU,
> > -             .data_type      = UVC_CTRL_DATA_TYPE_ENUM,
> > -             .menu_info      = power_line_frequency_controls,
> > -             .menu_count     = ARRAY_SIZE(power_line_frequency_controls),
> > -     },
> >       {
> >               .id             = V4L2_CID_HUE_AUTO,
> >               .entity         = UVC_GUID_UVC_PROCESSING,
> > @@ -730,6 +726,32 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> >       },
> >  };
> >
> > +static const
> > +struct uvc_control_mapping power_line_mapping_uvc11 = {
> > +     .id             = V4L2_CID_POWER_LINE_FREQUENCY,
> > +     .entity         = UVC_GUID_UVC_PROCESSING,
> > +     .selector       = UVC_PU_POWER_LINE_FREQUENCY_CONTROL,
> > +     .size           = 2,
> > +     .offset         = 0,
> > +     .v4l2_type      = V4L2_CTRL_TYPE_MENU,
> > +     .data_type      = UVC_CTRL_DATA_TYPE_ENUM,
> > +     .menu_info      = power_line_frequency_controls_uvc11,
> > +     .menu_count     = ARRAY_SIZE(power_line_frequency_controls_uvc11),
>
> ... use
>
>         .menu_count     = ARRAY_SIZE(power_line_frequency_controls) - 1,
>
> here. It will avoid duplicating the common menu items.
>
> > +};
> > +
> > +static const
> > +struct uvc_control_mapping power_line_mapping_uvc15 = {
>
> This holds on a single line (and same for uvc11).
>
> > +     .id             = V4L2_CID_POWER_LINE_FREQUENCY,
> > +     .entity         = UVC_GUID_UVC_PROCESSING,
> > +     .selector       = UVC_PU_POWER_LINE_FREQUENCY_CONTROL,
> > +     .size           = 2,
> > +     .offset         = 0,
> > +     .v4l2_type      = V4L2_CTRL_TYPE_MENU,
> > +     .data_type      = UVC_CTRL_DATA_TYPE_ENUM,
> > +     .menu_info      = power_line_frequency_controls_uvc15,
> > +     .menu_count     = ARRAY_SIZE(power_line_frequency_controls_uvc15),
> > +};
>
> How about turning those two into arrays (named uvc_ctrl_mappings_uvc11
> and uvc_ctrl_mappings_uvc15) ? uvc_ctrl_init_ctrl() would first loop
> over uvc_ctrl_mappings, and then over the version-specific arrays. This
> would ease support of further version-specific controls.
>

I like the idea, but in this particular case, we have to add a third
value for limited_powerline, which defeats the purpose :(.

What about  something like this:
https://git.kernel.org/pub/scm/linux/kernel/git/ribalda/linux.git/commit/?h=uvc-powerline-v4&id=f1ad7c4d8552843c785d4a22bba233d21f3aed45

Basically, leave an array with all the powerline definitions
(Disabled, 50,  60 and auto), and then hack around the index and
sizes.


> > +
> >  /* ------------------------------------------------------------------------
> >   * Utility functions
> >   */
> > @@ -2376,6 +2398,22 @@ static void uvc_ctrl_prune_entity(struct uvc_device *dev,
> >       }
> >  }
> >
> > +/*
> > + * The powerline control has different valid values depending on the
> > + * uvc version.
> > + */
> > +static void uvc_ctrl_init_powerline(struct uvc_video_chain *chain,
> > +                                 struct uvc_control *ctrl)
> > +{
> > +     if (chain->dev->uvc_version < 0x0150) {
> > +             __uvc_ctrl_add_mapping(chain, ctrl,
> > +                                    &power_line_mapping_uvc11);
> > +             return;
> > +     }
> > +
> > +     __uvc_ctrl_add_mapping(chain, ctrl, &power_line_mapping_uvc15);
> > +}
> > +
> >  /*
> >   * Add control information and hardcoded stock control mappings to the given
> >   * device.
> > @@ -2385,6 +2423,7 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
> >  {
> >       const struct uvc_control_info *info = uvc_ctrls;
> >       const struct uvc_control_info *iend = info + ARRAY_SIZE(uvc_ctrls);
> > +     static const u8 uvc_processing_guid[16] = UVC_GUID_UVC_PROCESSING;
>
> Please move this first, the driver declares static variables before the
> non-static ones.
Ack
>
> >       const struct uvc_control_mapping *mapping = uvc_ctrl_mappings;
> >       const struct uvc_control_mapping *mend =
> >               mapping + ARRAY_SIZE(uvc_ctrl_mappings);
> > @@ -2415,6 +2454,10 @@ static void uvc_ctrl_init_ctrl(struct uvc_video_chain *chain,
> >       if (!ctrl->initialized)
> >               return;
> >
> > +     if (uvc_entity_match_guid(ctrl->entity, uvc_processing_guid) &&
> > +         ctrl->info.selector == UVC_PU_POWER_LINE_FREQUENCY_CONTROL)
> > +             return uvc_ctrl_init_powerline(chain, ctrl);
> > +
> >       for (; mapping < mend; ++mapping) {
> >               if (uvc_entity_match_guid(ctrl->entity, mapping->entity) &&
> >                   ctrl->info.selector == mapping->selector)
>
> --
> Regards,
>
> Laurent Pinchart


-- 
Ricardo Ribalda