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

From: Ricardo Ribalda
Date: Tue Jul 01 2025 - 07:27:20 EST

On Sun, 29 Jun 2025 at 20:15, Laurent Pinchart
<laurent.pinchart@xxxxxxxxxxxxxxxx> 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@xxxxxxxxxxxx>
> > ---
> > 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