FROMGIT: media: docs: Document colorimetry class

Add a document for ext control colorimetry class.

Signed-off-by: Stanimir Varbanov <stanimir.varbanov@linaro.org>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
(cherry picked from commit 4e4053a28f37ab45ee9d13b77b1b9f53923b87b3
 git://linuxtv.org/media_tree.git master)
Bug: 175389589
Link: https://lkml.org/lkml/2021/3/23/646

Change-Id: I4aa8a420221ba6a98caa0fbac57aacdfc5e22224
Signed-off-by: Dikshita Agarwal <dikshita@codeaurora.org>

Documentation/userspace-api/media/v4l/common.rst

@@ -50,6 +50,7 @@ applicable to all devices.
     ext-ctrls-fm-tx
     ext-ctrls-fm-rx
     ext-ctrls-detect
+    ext-ctrls-colorimetry
     fourcc
     format
     planar-apis

Documentation/userspace-api/media/v4l/ext-ctrls-colorimetry.rst

@@ -0,0 +1,22 @@
+.. SPDX-License-Identifier: GFDL-1.1-no-invariants-or-later
+
+.. _colorimetry-controls:
+
+*****************************
+Colorimetry Control Reference
+*****************************
+
+The Colorimetry class includes controls for High Dynamic Range
+imaging for representing colors in digital images and video. The
+controls should be used for video and image encoding and decoding
+as well as in HDMI receivers and transmitters.
+
+Colorimetry Control IDs
+-----------------------
+
+.. _colorimetry-control-id:
+
+``V4L2_CID_COLORIMETRY_CLASS (class)``
+    The Colorimetry class descriptor. Calling
+    :ref:`VIDIOC_QUERYCTRL` for this control will
+    return a description of this control class.

Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst

@@ -358,6 +358,10 @@ still cause this situation.
       - 0xa20000
       - The class containing RF tuner controls. These controls are
 	described in :ref:`rf-tuner-controls`.
+    * - ``V4L2_CTRL_CLASS_COLORIMETRY``
+      - 0xa50000
+      - The class containing colorimetry controls. These controls are
+        described in :ref:`colorimetry-controls`.
 
 Return Value
 ============