Re: [PATCH v2 11/12] media: uvcvideo: Add support for V4L2_CID_CAMERA_ROTATION

[Ricardo Ribalda <ribalda@chromium.org>]

On Sun, 29 Jun 2025 at 20:15, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
>
> On Thu, Jun 05, 2025 at 05:53:04PM +0000, Ricardo Ribalda wrote:
> > Fetch the rotation from the fwnode and map it into a control.
> >
> > Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
> > ---
> >  drivers/media/usb/uvc/uvc_ctrl.c     | 22 +++++++++++++--
> >  drivers/media/usb/uvc/uvc_swentity.c | 55 ++++++++++++++++++++++++++++++++----
> >  drivers/media/usb/uvc/uvcvideo.h     |  5 ++++
> >  3 files changed, 74 insertions(+), 8 deletions(-)
> >
> > diff --git a/drivers/media/usb/uvc/uvc_ctrl.c b/drivers/media/usb/uvc/uvc_ctrl.c
> > index 59be62ae24a4219fa9d7aacf2ae7382c95362178..5788f0c0f6604da06a7bca1b9999d0957817e75e 100644
> > --- a/drivers/media/usb/uvc/uvc_ctrl.c
> > +++ b/drivers/media/usb/uvc/uvc_ctrl.c
> > @@ -378,11 +378,18 @@ static const struct uvc_control_info uvc_ctrls[] = {
> >       },
> >       {
> >               .entity         = UVC_GUID_SWENTITY,
> > -             .selector       = 0,
> > -             .index          = 0,
> > +             .selector       = UVC_SWENTITY_ORIENTATION,
> > +             .index          = UVC_SWENTITY_ORIENTATION,
> >               .size           = 1,
> >               .flags          = UVC_CTRL_FLAG_GET_CUR,
> >       },
> > +     {
> > +             .entity         = UVC_GUID_SWENTITY,
> > +             .selector       = UVC_SWENTITY_ROTATION,
> > +             .index          = UVC_SWENTITY_ROTATION,
> > +             .size           = 2,
> > +             .flags          = UVC_CTRL_FLAG_GET_RANGE,
> > +     },
> >  };
> >
> >  static const u32 uvc_control_classes[] = {
> > @@ -1025,7 +1032,7 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> >       {
> >               .id             = V4L2_CID_CAMERA_ORIENTATION,
> >               .entity         = UVC_GUID_SWENTITY,
> > -             .selector       = 0,
> > +             .selector       = UVC_SWENTITY_ORIENTATION,
> >               .size           = 8,
> >               .offset         = 0,
> >               .v4l2_type      = V4L2_CTRL_TYPE_MENU,
> > @@ -1033,6 +1040,15 @@ static const struct uvc_control_mapping uvc_ctrl_mappings[] = {
> >               .menu_mask      = GENMASK(V4L2_CAMERA_ORIENTATION_EXTERNAL,
> >                                         V4L2_CAMERA_ORIENTATION_FRONT),
> >       },
> > +     {
> > +             .id             = V4L2_CID_CAMERA_SENSOR_ROTATION,
> > +             .entity         = UVC_GUID_SWENTITY,
> > +             .selector       = UVC_SWENTITY_ROTATION,
> > +             .size           = 16,
> > +             .offset         = 0,
> > +             .v4l2_type      = V4L2_CTRL_TYPE_INTEGER,
> > +             .data_type      = UVC_CTRL_DATA_TYPE_UNSIGNED,
> > +     },
> >  };
> >
> >  /* ------------------------------------------------------------------------
> > diff --git a/drivers/media/usb/uvc/uvc_swentity.c b/drivers/media/usb/uvc/uvc_swentity.c
> > index 702a2c26e029a0655dade177ed2a9b88d7a4136d..60f3166addbeb7d2e431d107b23034d2d11a1812 100644
> > --- a/drivers/media/usb/uvc/uvc_swentity.c
> > +++ b/drivers/media/usb/uvc/uvc_swentity.c
> > @@ -10,10 +10,11 @@
> >  #include <media/v4l2-fwnode.h>
> >  #include "uvcvideo.h"
> >
> > -static int uvc_swentity_get_cur(struct uvc_device *dev, struct uvc_entity *entity,
> > -                             u8 cs, void *data, u16 size)
> > +static int uvc_swentity_get_orientation(struct uvc_device *dev,
> > +                                     struct uvc_entity *entity, u8 cs,
> > +                                     void *data, u16 size)
> >  {
> > -     if (size < 1)
> > +     if (cs != UVC_SWENTITY_ORIENTATION || size != 1)
> >               return -EINVAL;
> >
> >       switch (entity->swentity.props.orientation) {
> > @@ -30,6 +31,31 @@ static int uvc_swentity_get_cur(struct uvc_device *dev, struct uvc_entity *entit
> >       return 0;
> >  }
> >
> > +static int uvc_swentity_get_rotation(struct uvc_device *dev,
> > +                                  struct uvc_entity *entity, u8 cs, void *data,
> > +                                  u16 size)
> > +{
> > +     if (cs != UVC_SWENTITY_ROTATION || size != 2)
> > +             return -EINVAL;
> > +
> > +     ((u8 *)data)[0] = entity->swentity.props.rotation;
> > +     ((u8 *)data)[1] = entity->swentity.props.rotation >> 8;
> > +
> > +     return 0;
> > +}
> > +
> > +static int uvc_swentity_get_cur(struct uvc_device *dev, struct uvc_entity *entity,
> > +                             u8 cs, void *data, u16 size)
> > +{
> > +     switch (cs) {
> > +     case UVC_SWENTITY_ORIENTATION:
> > +             return uvc_swentity_get_orientation(dev, entity, cs, data, size);
> > +     case UVC_SWENTITY_ROTATION:
> > +             return uvc_swentity_get_rotation(dev, entity, cs, data, size);
> > +     }
> > +     return -EINVAL;
> > +}
> > +
> >  static int uvc_swentity_get_info(struct uvc_device *dev,
> >                                struct uvc_entity *entity, u8 cs, u8 *caps)
> >  {
> > @@ -37,11 +63,22 @@ static int uvc_swentity_get_info(struct uvc_device *dev,
> >       return 0;
> >  }
> >
> > +static int uvc_swentity_get_res(struct uvc_device *dev, struct uvc_entity *entity,
> > +                             u8 cs, void *res, u16 size)
> > +{
> > +     if (size == 0)
> > +             return -EINVAL;
>
> The get_cur functions return an error if the size doesn't match the
> expected size. I think you can return -EINVAL if size != 1.
>
> > +     ((u8 *)res)[0] = 1;
> > +     memset(res + 1, 0, size - 1);
>
> And drop the memset.
>
> > +     return 0;
> > +}
> > +
> >  int uvc_swentity_init(struct uvc_device *dev)
> >  {
> >       static const u8 uvc_swentity_guid[] = UVC_GUID_SWENTITY;
> >       struct v4l2_fwnode_device_properties props;
> >       struct uvc_entity *unit;
> > +     u8 controls = 0;
> >       int ret;
> >
> >       ret = v4l2_fwnode_device_parse(&dev->udev->dev, &props);
> > @@ -49,7 +86,11 @@ int uvc_swentity_init(struct uvc_device *dev)
> >               return dev_err_probe(&dev->intf->dev, ret,
> >                                    "Can't parse fwnode\n");
> >
> > -     if (props.orientation == V4L2_FWNODE_PROPERTY_UNSET)
> > +     if (props.orientation != V4L2_FWNODE_PROPERTY_UNSET)
> > +             controls |= BIT(UVC_SWENTITY_ORIENTATION);
> > +     if (props.rotation != V4L2_FWNODE_PROPERTY_UNSET)
> > +             controls |= BIT(UVC_SWENTITY_ROTATION);
> > +     if (!controls)
> >               return 0;
> >
> >       unit = uvc_alloc_entity(UVC_SWENTITY_UNIT, UVC_SWENTITY_UNIT_ID, 0, 1);
> > @@ -60,9 +101,13 @@ int uvc_swentity_init(struct uvc_device *dev)
> >       unit->swentity.props = props;
> >       unit->swentity.bControlSize = 1;
> >       unit->swentity.bmControls = (u8 *)unit + sizeof(*unit);
> > -     unit->swentity.bmControls[0] = 1;
> > +     unit->swentity.bmControls[0] = controls;
> >       unit->get_cur = uvc_swentity_get_cur;
> >       unit->get_info = uvc_swentity_get_info;
> > +     unit->get_res = uvc_swentity_get_res;
> > +     unit->get_def = uvc_swentity_get_rotation;
> > +     unit->get_min = uvc_swentity_get_rotation;
> > +     unit->get_max = uvc_swentity_get_rotation;
>
> Why do you support GET_DEF, GET_MIN and GET_MAX for rotation only ?

Orientation has enum type. It does not require min or max.

For get_def I could use get_cur, but 0 is as good as any other value
within range.

>
> >       strscpy(unit->name, "SWENTITY", sizeof(unit->name));
> >
> >       list_add_tail(&unit->list, &dev->entities);
> > diff --git a/drivers/media/usb/uvc/uvcvideo.h b/drivers/media/usb/uvc/uvcvideo.h
> > index d6da8ed3ad4cf3377df49923e051fe04d83d2e38..7cca0dc75d11f6a13bc4f09676a5a00e80cb38f7 100644
> > --- a/drivers/media/usb/uvc/uvcvideo.h
> > +++ b/drivers/media/usb/uvc/uvcvideo.h
> > @@ -45,6 +45,11 @@
> >  #define UVC_SWENTITY_UNIT            0x7ffd
> >  #define UVC_SWENTITY_UNIT_ID         0x101
> >
> > +enum {
> > +     UVC_SWENTITY_ORIENTATION,
> > +     UVC_SWENTITY_ROTATION
> > +};
> > +
> >  /* ------------------------------------------------------------------------
> >   * Driver specific constants.
> >   */
>
> --
> Regards,
>
> Laurent Pinchart



-- 
Ricardo Ribalda