1 files changed, 64 insertions, 0 deletions

diff --git a/drivers/media/video/v4l2-subdev.c b/drivers/media/video/v4l2-subdev.c
index 268d80584101..db6e859b93d4 100644
--- a/drivers/media/video/v4l2-subdev.c
+++ b/drivers/media/video/v4l2-subdev.c
@@ -387,6 +387,70 @@ const struct v4l2_file_operations v4l2_subdev_fops = {
         .poll = subdev_poll,
 };
 
+#ifdef CONFIG_MEDIA_CONTROLLER
+int v4l2_subdev_link_validate_default(struct v4l2_subdev *sd,
+                                      struct media_link *link,
+                                      struct v4l2_subdev_format *source_fmt,
+                                      struct v4l2_subdev_format *sink_fmt)
+{
+        if (source_fmt->format.width != sink_fmt->format.width
+            || source_fmt->format.height != sink_fmt->format.height
+            || source_fmt->format.code != sink_fmt->format.code)
+                return -EINVAL;
+
+        return 0;
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate_default);
+
+static int
+v4l2_subdev_link_validate_get_format(struct media_pad *pad,
+                                     struct v4l2_subdev_format *fmt)
+{
+        switch (media_entity_type(pad->entity)) {
+        case MEDIA_ENT_T_V4L2_SUBDEV:
+                fmt->which = V4L2_SUBDEV_FORMAT_ACTIVE;
+                fmt->pad = pad->index;
+                return v4l2_subdev_call(media_entity_to_v4l2_subdev(
+                                                pad->entity),
+                                        pad, get_fmt, NULL, fmt);
+        default:
+                WARN(1, "Driver bug! Wrong media entity type %d, entity %s\n",
+                     media_entity_type(pad->entity), pad->entity->name);
+                /* Fall through */
+        case MEDIA_ENT_T_DEVNODE_V4L:
+                return -EINVAL;
+        }
+}
+
+int v4l2_subdev_link_validate(struct media_link *link)
+{
+        struct v4l2_subdev *sink;
+        struct v4l2_subdev_format sink_fmt, source_fmt;
+        int rval;
+
+        rval = v4l2_subdev_link_validate_get_format(
+                link->source, &source_fmt);
+        if (rval < 0)
+                return 0;
+
+        rval = v4l2_subdev_link_validate_get_format(
+                link->sink, &sink_fmt);
+        if (rval < 0)
+                return 0;
+
+        sink = media_entity_to_v4l2_subdev(link->sink->entity);
+
+        rval = v4l2_subdev_call(sink, pad, link_validate, link,
+                                &source_fmt, &sink_fmt);
+        if (rval != -ENOIOCTLCMD)
+                return rval;
+
+        return v4l2_subdev_link_validate_default(
+                sink, link, &source_fmt, &sink_fmt);
+}
+EXPORT_SYMBOL_GPL(v4l2_subdev_link_validate);
+#endif /* CONFIG_MEDIA_CONTROLLER */
+
 void v4l2_subdev_init(struct v4l2_subdev *sd, const struct v4l2_subdev_ops *ops)
 {
         INIT_LIST_HEAD(&sd->list);