[PATCH] media: v4l2-subdev: Clearly document that the crop API won't be extended

[Laurent Pinchart]

The V4L2 subdev crop API has been marked as obsolete, deprecated by the
selection API. Despite this, it has recently been extended with streams
support. In hindsight this was a mistake. Make sure it doesn't happen
again by clearly documenting that no new extensions will be accepted.

Suggested-by: Hans Verkuil <hverkuil-cisco at xs4all.nl>
Signed-off-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
---
 .../userspace-api/media/v4l/vidioc-subdev-g-crop.rst        | 6 +++---
 include/uapi/linux/v4l2-subdev.h                            | 4 ++++
 2 files changed, 7 insertions(+), 3 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-crop.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-crop.rst
index 92d933631fda..88a748103a71 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-subdev-g-crop.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-g-crop.rst
@@ -37,9 +37,9 @@ Description
 
 .. note::
 
-    This is an :ref:`obsolete` interface and may be removed
-    in the future. It is superseded by
-    :ref:`the selection API <VIDIOC_SUBDEV_G_SELECTION>`.
+    This is an :ref:`obsolete` interface and may be removed in the future. It is
+    superseded by :ref:`the selection API <VIDIOC_SUBDEV_G_SELECTION>`. No new
+    extensions to the :c:type:`v4l2_subdev_crop` structure will be accepted.
 
 To retrieve the current crop rectangle applications set the ``pad``
 field of a struct :c:type:`v4l2_subdev_crop` to the
diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
index 7048c51581c6..81a24bd38003 100644
--- a/include/uapi/linux/v4l2-subdev.h
+++ b/include/uapi/linux/v4l2-subdev.h
@@ -50,6 +50,10 @@ struct v4l2_subdev_format {
  * @rect: pad crop rectangle boundaries
  * @stream: stream number, defined in subdev routing
  * @reserved: drivers and applications must zero this array
+ *
+ * The subdev crop API is an obsolete interface and may be removed in the
+ * future. It is superseded by the selection API. No new extensions to this
+ * structure will be accepted.
  */
 struct v4l2_subdev_crop {
 	__u32 which;
-- 
Regards,

Laurent Pinchart