media: uvcvideo: Introduce dev->meta_formats

Right now, there driver supports devices with one or two metadata
formats. Prepare it to support more than two metadata formats.

This is achieved with the introduction of a new field `meta_formats`,
that contains the array of metadata formats supported by the device, in
the order expected by userspace.

Suggested-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Hans de Goede <hansg@kernel.org>
Link: https://lore.kernel.org/r/20250707-uvc-meta-v8-3-ed17f8b1218b@chromium.org
Signed-off-by: Hans de Goede <hansg@kernel.org>
Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>

Author: ribalda

drivers/media/usb/uvc/uvc_driver.c

@@ -2293,6 +2293,8 @@ static int uvc_probe(struct usb_interface *intf,
 		goto error;
 	}
 
+	uvc_meta_init(dev);
+
 	if (dev->quirks & UVC_QUIRK_NO_RESET_RESUME)
 		udev->quirks &= ~USB_QUIRK_RESET_RESUME;
 

drivers/media/usb/uvc/uvc_metadata.c

@@ -64,14 +64,20 @@ static int uvc_meta_v4l2_try_format(struct file *file, void *fh,
 	struct uvc_device *dev = stream->dev;
 	struct v4l2_meta_format *fmt = &format->fmt.meta;
 	u32 fmeta = fmt->dataformat;
+	u32 i;
 
 	if (format->type != vfh->vdev->queue->type)
 		return -EINVAL;
 
+	for (i = 0; (fmeta != dev->meta_formats[i]) && dev->meta_formats[i];
+	     i++)
+		;
+	if (!dev->meta_formats[i])
+		fmeta = V4L2_META_FMT_UVC;
+
 	memset(fmt, 0, sizeof(*fmt));
 
-	fmt->dataformat = fmeta == dev->info->meta_format
-			? fmeta : V4L2_META_FMT_UVC;
+	fmt->dataformat = fmeta;
 	fmt->buffersize = UVC_METADATA_BUF_SIZE;
 
 	return 0;
@@ -112,17 +118,21 @@ static int uvc_meta_v4l2_enum_formats(struct file *file, void *fh,
 	struct v4l2_fh *vfh = file->private_data;
 	struct uvc_streaming *stream = video_get_drvdata(vfh->vdev);
 	struct uvc_device *dev = stream->dev;
-	u32 index = fdesc->index;
+	u32 i;
+
+	if (fdesc->type != vfh->vdev->queue->type)
+		return -EINVAL;
 
-	if (fdesc->type != vfh->vdev->queue->type ||
-	    index > 1U || (index && !dev->info->meta_format))
+	for (i = 0; (i < fdesc->index) && dev->meta_formats[i]; i++)
+		;
+	if (!dev->meta_formats[i])
 		return -EINVAL;
 
 	memset(fdesc, 0, sizeof(*fdesc));
 
 	fdesc->type = vfh->vdev->queue->type;
-	fdesc->index = index;
-	fdesc->pixelformat = index ? dev->info->meta_format : V4L2_META_FMT_UVC;
+	fdesc->index = i;
+	fdesc->pixelformat = dev->meta_formats[i];
 
 	return 0;
 }
@@ -168,3 +178,17 @@ int uvc_meta_register(struct uvc_streaming *stream)
 					 V4L2_BUF_TYPE_META_CAPTURE,
 					 &uvc_meta_fops, &uvc_meta_ioctl_ops);
 }
+
+void uvc_meta_init(struct uvc_device *dev)
+{
+	unsigned int i = 0;
+
+	dev->meta_formats[i++] = V4L2_META_FMT_UVC;
+
+	if (dev->info->meta_format &&
+	    !WARN_ON(dev->info->meta_format == V4L2_META_FMT_UVC))
+		dev->meta_formats[i++] = dev->info->meta_format;
+
+	 /* IMPORTANT: for new meta-formats update UVC_MAX_META_DATA_FORMATS. */
+	dev->meta_formats[i++] = 0;
+}

drivers/media/usb/uvc/uvcvideo.h

@@ -575,6 +575,8 @@ struct uvc_status {
 	};
 } __packed;
 
+#define UVC_MAX_META_DATA_FORMATS 3
+
 struct uvc_device {
 	struct usb_device *udev;
 	struct usb_interface *intf;
@@ -585,6 +587,9 @@ struct uvc_device {
 
 	const struct uvc_device_info *info;
 
+	/* Zero-ended list of meta formats */
+	u32 meta_formats[UVC_MAX_META_DATA_FORMATS + 1];
+
 	atomic_t nmappings;
 
 	/* Video control interface */
@@ -722,6 +727,7 @@ int uvc_query_ctrl(struct uvc_device *dev, u8 query, u8 unit,
 void uvc_video_clock_update(struct uvc_streaming *stream,
 			    struct vb2_v4l2_buffer *vbuf,
 			    struct uvc_buffer *buf);
+void uvc_meta_init(struct uvc_device *dev);
 int uvc_meta_register(struct uvc_streaming *stream);
 
 int uvc_register_video_device(struct uvc_device *dev,