Re: [PATCH v3] media: sun6i-mipi-csi2: Use V4L2 subdev active state

[Paul Kocialkowski <paulk@sys-base.io>]

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Hi Arash,

On Wed 22 Apr 26, 08:23, arash golgol wrote:
> I was hoping this patch would make its way into media-tree, but it seems
> it hasn't been applied yet.
> 
> Is there anything missing or any modifications needed from my side?
> I'd appreciate any feedback.

I would like to test this patch before it gets in, but didn't manage to find
the time. The same should probably also apply to the a83t mipi csi-2 driver,
which is structured the same way.

Thanks for your work,

Paul


> Regards,
> Arash Golgol
> 
> On Sat, Feb 14, 2026 at 8:40 AM Arash Golgol <arash.golgol@gmail.com> wrote:
> >
> > Use the V4L2 subdev active state API to store the active format.
> > This simplifies the driver not only by dropping the bridge mbus_format
> > field, but it also allows dropping the bridge lock, replaced with
> > the state lock.
> >
> > The sun6i-mipi-csi2 hardware does not perform any format conversion.
> > Enforce identical formats on the sink and source pads in the set_fmt()
> > and init_state() callbacks.
> >
> > Signed-off-by: Arash Golgol <arash.golgol@gmail.com>
> > Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> > ---
> > Changes in v3:
> >     - link to v2: https://patchwork.kernel.org/project/linux-media/patch/20260209055529.16644-1-arash.golgol@gmail.com/
> >     - Keep error path jumping to error_v4l2_notifier_cleanup on
> >     bridge setup failure
> >
> > Changes in v2:
> >     - link to v1: https://patchwork.kernel.org/project/linux-media/patch/20260206123455.46476-1-arash.golgol@gmail.com/
> >     - Simplify control flow by dropping the else at end of s_stream()
> >     - Call v4l2_subdev_cleanup() on bridge setup failure before
> >     notifier registration
> >
> >  .../sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c   | 107 +++++++++---------
> >  .../sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.h   |   2 -
> >  2 files changed, 53 insertions(+), 56 deletions(-)
> >
> > diff --git a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
> > index b06cb73015cd..682bdd82098c 100644
> > --- a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
> > +++ b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.c
> > @@ -95,12 +95,12 @@ static void sun6i_mipi_csi2_disable(struct sun6i_mipi_csi2_device *csi2_dev)
> >                            SUN6I_MIPI_CSI2_CTL_EN, 0);
> >  }
> >
> > -static void sun6i_mipi_csi2_configure(struct sun6i_mipi_csi2_device *csi2_dev)
> > +static void sun6i_mipi_csi2_configure(struct sun6i_mipi_csi2_device *csi2_dev,
> > +                                      const struct v4l2_mbus_framefmt *mbus_format)
> >  {
> >         struct regmap *regmap = csi2_dev->regmap;
> >         unsigned int lanes_count =
> >                 csi2_dev->bridge.endpoint.bus.mipi_csi2.num_data_lanes;
> > -       struct v4l2_mbus_framefmt *mbus_format = &csi2_dev->bridge.mbus_format;
> >         const struct sun6i_mipi_csi2_format *format;
> >         struct device *dev = csi2_dev->dev;
> >         u32 version = 0;
> > @@ -173,7 +173,8 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> >         struct v4l2_subdev *source_subdev = csi2_dev->bridge.source_subdev;
> >         union phy_configure_opts dphy_opts = { 0 };
> >         struct phy_configure_opts_mipi_dphy *dphy_cfg = &dphy_opts.mipi_dphy;
> > -       struct v4l2_mbus_framefmt *mbus_format = &csi2_dev->bridge.mbus_format;
> > +       struct v4l2_subdev_state *state;
> > +       const struct v4l2_mbus_framefmt *mbus_format;
> >         const struct sun6i_mipi_csi2_format *format;
> >         struct phy *dphy = csi2_dev->dphy;
> >         struct device *dev = csi2_dev->dev;
> > @@ -183,8 +184,12 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> >         unsigned long pixel_rate;
> >         int ret;
> >
> > -       if (!source_subdev)
> > -               return -ENODEV;
> > +       state = v4l2_subdev_lock_and_get_active_state(subdev);
> > +
> > +       if (!source_subdev) {
> > +               ret = -ENODEV;
> > +               goto unlock;
> > +       }
> >
> >         if (!on) {
> >                 v4l2_subdev_call(source_subdev, video, s_stream, 0);
> > @@ -196,7 +201,7 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> >
> >         ret = pm_runtime_resume_and_get(dev);
> >         if (ret < 0)
> > -               return ret;
> > +               goto unlock;
> >
> >         /* Sensor Pixel Rate */
> >
> > @@ -222,6 +227,8 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> >                 goto error_pm;
> >         }
> >
> > +       mbus_format = v4l2_subdev_state_get_format(state,
> > +                                                  SUN6I_MIPI_CSI2_PAD_SINK);
> >         format = sun6i_mipi_csi2_format_find(mbus_format->code);
> >         if (WARN_ON(!format)) {
> >                 ret = -ENODEV;
> > @@ -260,7 +267,7 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> >
> >         /* Controller */
> >
> > -       sun6i_mipi_csi2_configure(csi2_dev);
> > +       sun6i_mipi_csi2_configure(csi2_dev, mbus_format);
> >         sun6i_mipi_csi2_enable(csi2_dev);
> >
> >         /* D-PHY */
> > @@ -277,7 +284,8 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> >         if (ret && ret != -ENOIOCTLCMD)
> >                 goto disable;
> >
> > -       return 0;
> > +       ret = 0;
> > +       goto unlock;
> >
> >  disable:
> >         phy_power_off(dphy);
> > @@ -286,6 +294,8 @@ static int sun6i_mipi_csi2_s_stream(struct v4l2_subdev *subdev, int on)
> >  error_pm:
> >         pm_runtime_put(dev);
> >
> > +unlock:
> > +       v4l2_subdev_unlock_state(state);
> >         return ret;
> >  }
> >
> > @@ -308,21 +318,23 @@ sun6i_mipi_csi2_mbus_format_prepare(struct v4l2_mbus_framefmt *mbus_format)
> >  static int sun6i_mipi_csi2_init_state(struct v4l2_subdev *subdev,
> >                                       struct v4l2_subdev_state *state)
> >  {
> > -       struct sun6i_mipi_csi2_device *csi2_dev = v4l2_get_subdevdata(subdev);
> > -       unsigned int pad = SUN6I_MIPI_CSI2_PAD_SINK;
> > -       struct v4l2_mbus_framefmt *mbus_format =
> > -               v4l2_subdev_state_get_format(state, pad);
> > -       struct mutex *lock = &csi2_dev->bridge.lock;
> > +       unsigned int pad;
> >
> > -       mutex_lock(lock);
> > +       /*
> > +        * This subdev does not perform format conversion,
> > +        * initialize both pads identically.
> > +        */
> > +       for (pad = 0; pad < subdev->entity.num_pads; pad++) {
> > +               struct v4l2_mbus_framefmt *mbus_format;
> >
> > -       mbus_format->code = sun6i_mipi_csi2_formats[0].mbus_code;
> > -       mbus_format->width = 640;
> > -       mbus_format->height = 480;
> > +               mbus_format = v4l2_subdev_state_get_format(state, pad);
> >
> > -       sun6i_mipi_csi2_mbus_format_prepare(mbus_format);
> > +               mbus_format->code = sun6i_mipi_csi2_formats[0].mbus_code;
> > +               mbus_format->width = 640;
> > +               mbus_format->height = 480;
> >
> > -       mutex_unlock(lock);
> > +               sun6i_mipi_csi2_mbus_format_prepare(mbus_format);
> > +       }
> >
> >         return 0;
> >  }
> > @@ -340,53 +352,32 @@ sun6i_mipi_csi2_enum_mbus_code(struct v4l2_subdev *subdev,
> >         return 0;
> >  }
> >
> > -static int sun6i_mipi_csi2_get_fmt(struct v4l2_subdev *subdev,
> > -                                  struct v4l2_subdev_state *state,
> > -                                  struct v4l2_subdev_format *format)
> > -{
> > -       struct sun6i_mipi_csi2_device *csi2_dev = v4l2_get_subdevdata(subdev);
> > -       struct v4l2_mbus_framefmt *mbus_format = &format->format;
> > -       struct mutex *lock = &csi2_dev->bridge.lock;
> > -
> > -       mutex_lock(lock);
> > -
> > -       if (format->which == V4L2_SUBDEV_FORMAT_TRY)
> > -               *mbus_format = *v4l2_subdev_state_get_format(state,
> > -                                                            format->pad);
> > -       else
> > -               *mbus_format = csi2_dev->bridge.mbus_format;
> > -
> > -       mutex_unlock(lock);
> > -
> > -       return 0;
> > -}
> > -
> >  static int sun6i_mipi_csi2_set_fmt(struct v4l2_subdev *subdev,
> >                                    struct v4l2_subdev_state *state,
> >                                    struct v4l2_subdev_format *format)
> >  {
> > -       struct sun6i_mipi_csi2_device *csi2_dev = v4l2_get_subdevdata(subdev);
> > -       struct v4l2_mbus_framefmt *mbus_format = &format->format;
> > -       struct mutex *lock = &csi2_dev->bridge.lock;
> > +       struct v4l2_mbus_framefmt *fmt;
> >
> > -       mutex_lock(lock);
> > +       /* The format on the source pad always matches the sink pad. */
> > +       if (format->pad != SUN6I_MIPI_CSI2_PAD_SINK)
> > +               return v4l2_subdev_get_fmt(subdev, state, format);
> >
> > -       sun6i_mipi_csi2_mbus_format_prepare(mbus_format);
> > +       sun6i_mipi_csi2_mbus_format_prepare(&format->format);
> >
> > -       if (format->which == V4L2_SUBDEV_FORMAT_TRY)
> > -               *v4l2_subdev_state_get_format(state, format->pad) =
> > -                       *mbus_format;
> > -       else
> > -               csi2_dev->bridge.mbus_format = *mbus_format;
> > +       /* Set the format on the sink pad. */
> > +       fmt = v4l2_subdev_state_get_format(state, format->pad);
> > +       *fmt = format->format;
> >
> > -       mutex_unlock(lock);
> > +       /* Propagate the format to the source pad. */
> > +       fmt = v4l2_subdev_state_get_format(state, SUN6I_MIPI_CSI2_PAD_SOURCE);
> > +       *fmt = format->format;
> >
> >         return 0;
> >  }
> >
> >  static const struct v4l2_subdev_pad_ops sun6i_mipi_csi2_pad_ops = {
> >         .enum_mbus_code = sun6i_mipi_csi2_enum_mbus_code,
> > -       .get_fmt        = sun6i_mipi_csi2_get_fmt,
> > +       .get_fmt        = v4l2_subdev_get_fmt,
> >         .set_fmt        = sun6i_mipi_csi2_set_fmt,
> >  };
> >
> > @@ -502,8 +493,6 @@ static int sun6i_mipi_csi2_bridge_setup(struct sun6i_mipi_csi2_device *csi2_dev)
> >         bool notifier_registered = false;
> >         int ret;
> >
> > -       mutex_init(&bridge->lock);
> > -
> >         /* V4L2 Subdev */
> >
> >         v4l2_subdev_init(subdev, &sun6i_mipi_csi2_subdev_ops);
> > @@ -532,6 +521,12 @@ static int sun6i_mipi_csi2_bridge_setup(struct sun6i_mipi_csi2_device *csi2_dev)
> >         if (ret)
> >                 return ret;
> >
> > +       /* V4L2 Subdev finalize */
> > +
> > +       ret = v4l2_subdev_init_finalize(subdev);
> > +       if (ret < 0)
> > +               goto error_media_entity_cleanup;
> > +
> >         /* V4L2 Async */
> >
> >         v4l2_async_subdev_nf_init(notifier, subdev);
> > @@ -565,6 +560,9 @@ static int sun6i_mipi_csi2_bridge_setup(struct sun6i_mipi_csi2_device *csi2_dev)
> >  error_v4l2_notifier_cleanup:
> >         v4l2_async_nf_cleanup(notifier);
> >
> > +       v4l2_subdev_cleanup(subdev);
> > +
> > +error_media_entity_cleanup:
> >         media_entity_cleanup(&subdev->entity);
> >
> >         return ret;
> > @@ -579,6 +577,7 @@ sun6i_mipi_csi2_bridge_cleanup(struct sun6i_mipi_csi2_device *csi2_dev)
> >         v4l2_async_unregister_subdev(subdev);
> >         v4l2_async_nf_unregister(notifier);
> >         v4l2_async_nf_cleanup(notifier);
> > +       v4l2_subdev_cleanup(subdev);
> >         media_entity_cleanup(&subdev->entity);
> >  }
> >
> > diff --git a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.h b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.h
> > index 24b15e34b5e8..d72dfbd6a993 100644
> > --- a/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.h
> > +++ b/drivers/media/platform/sunxi/sun6i-mipi-csi2/sun6i_mipi_csi2.h
> > @@ -32,8 +32,6 @@ struct sun6i_mipi_csi2_bridge {
> >         struct media_pad                pads[SUN6I_MIPI_CSI2_PAD_COUNT];
> >         struct v4l2_fwnode_endpoint     endpoint;
> >         struct v4l2_async_notifier      notifier;
> > -       struct v4l2_mbus_framefmt       mbus_format;
> > -       struct mutex                    lock; /* Mbus format lock. */
> >
> >         struct v4l2_subdev              *source_subdev;
> >  };
> > --
> > 2.34.1
> >

-- 
Paul Kocialkowski,

Independent contractor - sys-base - https://www.sys-base.io/
Free software developer - https://www.paulk.fr/

Expert in multimedia, graphics and embedded hardware support with Linux.

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