media: sun4i_csi: Implement link validate for sun4i_csi subdev

commit 2dc5d5d upstream.

The sun4i_csi driver doesn't implement link validation for the subdev it
registers, leaving the link between the subdev and its source
unvalidated. Fix it, using the v4l2_subdev_link_validate() helper.

Fixes: 577bbf2 ("media: sunxi: Add A10 CSI driver")
Cc: stable@vger.kernel.org
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Acked-by: Chen-Yu Tsai <wens@csie.org>
Reviewed-by: Tomi Valkeinen <tomi.valkeinen+renesas@ideasonboard.com>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: Laurent Pinchart

drivers/media/platform/sunxi/sun4i-csi/sun4i_csi.c

@@ -39,6 +39,10 @@ static const struct media_entity_operations sun4i_csi_video_entity_ops = {
 	.link_validate = v4l2_subdev_link_validate,
 };
 
+static const struct media_entity_operations sun4i_csi_subdev_entity_ops = {
+	.link_validate = v4l2_subdev_link_validate,
+};
+
 static int sun4i_csi_notify_bound(struct v4l2_async_notifier *notifier,
 				  struct v4l2_subdev *subdev,
 				  struct v4l2_async_connection *asd)
@@ -214,6 +218,7 @@ static int sun4i_csi_probe(struct platform_device *pdev)
 	subdev->internal_ops = &sun4i_csi_subdev_internal_ops;
 	subdev->flags = V4L2_SUBDEV_FL_HAS_DEVNODE | V4L2_SUBDEV_FL_HAS_EVENTS;
 	subdev->entity.function = MEDIA_ENT_F_VID_IF_BRIDGE;
+	subdev->entity.ops = &sun4i_csi_subdev_entity_ops;
 	subdev->owner = THIS_MODULE;
 	snprintf(subdev->name, sizeof(subdev->name), "sun4i-csi-0");
 	v4l2_set_subdevdata(subdev, csi);