[PATCH v6 0/6] v4l2: add support for colorspace conversion API (CSC) for video capture and subdevices

[PATCH v6 0/6] v4l2: add support for colorspace conversion API (CSC) for video capture and subdevices

[Dafna Hirschfeld]

For video capture it is the driver that reports the colorspace, transfer function,
Y'CbCr/HSV encoding and quantization range used by the video, and there is no way
to request something different, even though many HDTV receivers have some sort of
colorspace conversion capabilities.

For output video this feature already exists since the application
specifies this information for the video format it will send out, and
the transmitter will enable any available CSC if a format conversion has
to be performed in order to match the capabilities of the sink.

For video capture we propose adding new v4l2_pix_format flag:
V4L2_PIX_FMT_FLAG_SET_CSC. The flag is set by the application,
the driver will interpret the fields 'colorspace', 'xfer_func',
'ycbcr_enc/hsv_enc' and 'quantization' as the requested colorspace information
and will attempt to do the conversion it supports.

Drivers set the flags
V4L2_FMT_FLAG_CSC_COLORSPACE,
V4L2_FMT_FLAG_CSC_XFER_FUNC,
V4L2_FMT_FLAG_CSC_YCBCR_ENC/V4L2_FMT_FLAG_CSC_HSV_ENC,
V4L2_FMT_FLAG_CSC_QUANTIZATION,

in the flags field of the struct v4l2_fmtdesc during enumeration to
indicate that they support colorspace conversion for the respective field.

The same API is added for the subdevices. With the flag
V4L2_MBUS_FRAMEFMT_SET_CSC set by the application in VIDIOC_SUBDEV_S_FMT
ioctl and the flags
V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE,
V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC,
V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC/V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION,

set by the driver in the VIDIOC_SUBDEV_ENUM_MBUS_CODE ioctl.

For subdevices, new 'flags' fields were added to the structs
v4l2_subdev_mbus_code_enum, v4l2_mbus_framefmt which are borrowed from the
'reserved' field. In the struct 'v4l2_mbus_framefmt' and reserved2 field
is added before the flags due to padding.

Drivers do not have to actually look at the flags. If the flags are not
set, then the colorspace, xfer_func, ycbcr_enc/hsv_enc and quantization
fields are set to the default values by the core, i.e. just pass on the
received format without conversion.

The patchset includes a patch in vivid that implements the API for video
capture devices and a patch in rkisp1 driver that implement the API for
subdevices.

In rkisp1, the API is used to allow userspace to set the quantization for
YUV formats on the source pad of the isp entity. The quantization is read-only
on the other entities and pads and does not have to be propagated.

I also removed the TODO item 'Handle quantization'
and added the TODO item 'Add uapi docs. Remember to add documentation of how quantization is handled.'

A patchset for v4l-utils to support the API: https://patchwork.kernel.org/cover/11642587/

To test the patchset, follow the instructions from here: https://patchwork.kernel.org/cover/11642587/
with the exception that the branch changed, so the clone command should be:

git clone --single-branch --branch rkisp1-quant-v6-aug-17  https://gitlab.collabora.com/dafna/v4l-utils.git


Patches Summary:
----------------
patch 1 - moves the description of the v4l2_pix_format flags in the Documentation to the right
place where it should be. This is just a fix.

patch 2 - Adds the API for video devices - Adds the new macros and fields and their documentation.
This is only for video devices.

patch 3 - uses the API in the capture device of vivid. Using the API, userspace is allowed to:
1. Set the colorspace
2. set the xfer_func
3. Set the ycbcr_enc function for YUV formats.
4. Set the hsv_enc function for HSV formats
5. Set the quantization for YUV and RGB formats.

patch 4 - Adds the API for subdevices - Adds the new macros and fields and their documentation.
It also replaces the ycbcr_enc field of 'struct v4l2_mbus_framefmt' with a union that includes
also hsv_enc and adds support for CSC on hsv_enc for subdevices.

patch 5 - use the API to allow userspace to set the quantization on the isp source pad.

patch 6 - sets the flags to 0 in the mbus enumeration of the resizer.

Changes from v5:
----------------
- reordering the colorspace fields in the documentation and their flags in the header files
to the order 'colorspace', 'transfer function' 'Y'CbCr/ HSV encoding' , 'quantization'

- in patch 3, move the helpers 'vivid_is_*_valid' as static inline 'v4l2_is_*_valid' in v4l2-common.h , reorder the
handling of the colorspace fields, and drop a redundant assignment 'dev->tpg.quantization = mp->quantization'

- squashing patches 4,5 into one

- in patch 4, changing the documentation in file subdev-formats.rst to not mention 'capture stream'
since this term is only relevant to video devices, so I changed the existing documentations:

"must be set by the driver for capture streams and by the application for output streams"

with "must be set by the driver for subdevices"
and documenting that the CSC is only for source pads.


- In patches 2,4,  in the doc of V4L2_MBUS_FRAMEFMT_SET_CSC/V4L2_PIX_FMT_FLAG_SET_CSC, replacing '0' with ``*_DEFAULT``

- in patch 5 (patch 6 in v2) : replace return of V4L2_QUANTIZATION_DEFAULT was the right value.

Changes from v4:
----------------
- This time I didn't to this patchset the patches from 'media: staging: rkisp1: bugs fixes and vars renames'
but note that this patchset is rebased on that patchset.

- I added the fields 'colorspace' 'xfer_func' to the list of fields that the CSC API supports due to
comment from Hans Verkuil. Also the vivid implementation is extended to support those fields.

- I split the patch that adds the API into two patches. One for video devices and one patch for subdevices.
This is because the two APIs are actually independent and it is easier to maintain and review two small patches
than one big patch.
Also, it can be decided that only one of those patches be accepted.

- I changed the flags fields in 'struct v4l2_mbus_framefmt'  to __u32 and added a reserved2 field before it due to
padding.

- I changed the patch for rkisp1 so that the quantization can be set by userspace only on the source pad of
the isp entity and is read-only and set always to default for all other entities and pads.
The driver also does not validate matching of the quantization between entities.

- Added a patch to the rkisp1-resizer that sets the flags to 0 when enumerating the mbus codes.
This is because the resizer reports the same formats as the source pad of the isp entity but does
not support the quantization conversion.

- various small fixes due to feedback.

Changes from v3:
----------------
- patches 1,2,3,7,8 are new (rkisp1 bug fixes, move v4l2-pixfmt flags docs, vivid patch, support for HSV media bus)

- patch 4 (The API):
1) reformulate the Documentation according to comments from Verkuil and Tomasz Figa
2) remove the code in drivers/media/v4l2-core/v4l2-subdev.c and drivers/media/v4l2-core/v4l2-ioctl.c
so that except of the new macros and fields no new code is added to the core

- patches 5,6 - refactor the rkisp1 implementation so that the userspace should set the quantization separately
to each entity. In patch 6 the validation callbacks make sure the quantizations matches.

Dafna Hirschfeld (6):
  media: Documentation: v4l: move table of v4l2_pix_format(_mplane)
    flags to pixfmt-v4l2.rst
  v4l2: add support for colorspace conversion API (CSC) for video
    capture
  media: vivid: Add support to the CSC API
  v4l2: extend the CSC API to subdevice.
  media: staging: rkisp1: allow quantization setting by userspace on the
    isp source pad
  media: staging: rkisp1: rsz: set flags to 0 in enum_mbus_code cb

 .../media/v4l/pixfmt-reserved.rst             | 17 ----
 .../media/v4l/pixfmt-v4l2-mplane.rst          | 16 +--
 .../userspace-api/media/v4l/pixfmt-v4l2.rst   | 81 ++++++++++++++-
 .../media/v4l/subdev-formats.rst              | 98 +++++++++++++++++--
 .../media/v4l/vidioc-enum-fmt.rst             | 35 +++++++
 .../v4l/vidioc-subdev-enum-mbus-code.rst      | 51 +++++++++-
 .../media/videodev2.h.rst.exceptions          |  7 +-
 .../media/test-drivers/vivid/vivid-vid-cap.c  | 38 +++++--
 .../test-drivers/vivid/vivid-vid-common.c     | 25 +++++
 drivers/staging/media/rkisp1/TODO             |  2 +-
 drivers/staging/media/rkisp1/rkisp1-capture.c | 10 --
 drivers/staging/media/rkisp1/rkisp1-isp.c     | 20 +++-
 drivers/staging/media/rkisp1/rkisp1-resizer.c |  1 +
 include/media/v4l2-common.h                   | 39 ++++++++
 include/uapi/linux/v4l2-mediabus.h            | 17 +++-
 include/uapi/linux/v4l2-subdev.h              |  9 +-
 include/uapi/linux/videodev2.h                |  6 ++
 17 files changed, 402 insertions(+), 70 deletions(-)

-- 
2.17.1

[PATCH v6 1/6] media: Documentation: v4l: move table of v4l2_pix_format(_mplane) flags to pixfmt-v4l2.rst

[Dafna Hirschfeld]

The table of the flags of the structs
v4l2_pix_format(_mplane) is currently in pixfmt-reserved.rst
which is wrong, it should be in pixfmt-v4l2.rst

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
---
 .../userspace-api/media/v4l/pixfmt-reserved.rst | 17 -----------------
 .../userspace-api/media/v4l/pixfmt-v4l2.rst     | 17 +++++++++++++++++
 .../media/videodev2.h.rst.exceptions            |  2 +-
 3 files changed, 18 insertions(+), 18 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
index 59b9e7238f90..74ab6b5ce294 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-reserved.rst
@@ -263,20 +263,3 @@ please make a proposal on the linux-media mailing list.
 	of tiles, resulting in 32-aligned resolutions for the luminance plane
 	and 16-aligned resolutions for the chrominance plane (with 2x2
 	subsampling).
-
-.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
-
-.. _format-flags:
-
-.. flat-table:: Format Flags
-    :header-rows:  0
-    :stub-columns: 0
-    :widths:       3 1 4
-
-    * - ``V4L2_PIX_FMT_FLAG_PREMUL_ALPHA``
-      - 0x00000001
-      - The color values are premultiplied by the alpha channel value. For
-	example, if a light blue pixel with 50% transparency was described
-	by RGBA values (128, 192, 255, 128), the same pixel described with
-	premultiplied colors would be described by RGBA values (64, 96,
-	128, 128)
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
index e0ee2823ab1f..56a2952de873 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
@@ -174,3 +174,20 @@ Single-planar format structure
         This information supplements the ``colorspace`` and must be set by
 	the driver for capture streams and by the application for output
 	streams, see :ref:`colorspaces`.
+
+.. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
+
+.. _format-flags:
+
+.. flat-table:: Format Flags
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+    * - ``V4L2_PIX_FMT_FLAG_PREMUL_ALPHA``
+      - 0x00000001
+      - The color values are premultiplied by the alpha channel value. For
+        example, if a light blue pixel with 50% transparency was described
+	by RGBA values (128, 192, 255, 128), the same pixel described with
+	premultiplied colors would be described by RGBA values (64, 96,
+	128, 128)
diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
index ca05e4e126b2..659799cc1eca 100644
--- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
+++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
@@ -180,7 +180,7 @@ replace define V4L2_CAP_IO_MC device-capabilities
 
 # V4L2 pix flags
 replace define V4L2_PIX_FMT_PRIV_MAGIC :c:type:`v4l2_pix_format`
-replace define V4L2_PIX_FMT_FLAG_PREMUL_ALPHA reserved-formats
+replace define V4L2_PIX_FMT_FLAG_PREMUL_ALPHA format-flags
 
 # V4L2 format flags
 replace define V4L2_FMT_FLAG_COMPRESSED fmtdesc-flags
-- 
2.17.1

[PATCH v6 2/6] v4l2: add support for colorspace conversion API (CSC) for video capture

[Dafna Hirschfeld]

For video capture it is the driver that reports the colorspace,
transfer function, Y'CbCr/HSV encoding and quantization range
used by the video, and there is no way to request something
different, even though many HDTV receivers have some sort of
colorspace conversion capabilities.

For output video this feature already exists since the application
specifies this information for the video format it will send out, and
the transmitter will enable any available CSC if a format conversion has
to be performed in order to match the capabilities of the sink.

For video capture we propose adding new v4l2_pix_format flag:
V4L2_PIX_FMT_FLAG_SET_CSC. The flag is set by the application,
the driver will interpret the colorspace, xfer_func, ycbcr_enc/hsv_enc
and quantization fields as the requested colorspace information and will
attempt to do the conversion it supports.

Drivers set the flags
V4L2_FMT_FLAG_CSC_COLORSPACE,
V4L2_FMT_FLAG_CSC_XFER_FUNC,
V4L2_FMT_FLAG_CSC_YCBCR_ENC/V4L2_FMT_FLAG_CSC_HSV_ENC,
V4L2_FMT_FLAG_CSC_QUANTIZATION,
in the flags field of the struct v4l2_fmtdesc during enumeration to
indicate that they support colorspace conversion for the respective field.

Drivers do not have to actually look at the flags. If the flags are not
set, then the fields 'colorspace', 'xfer_func', 'ycbcr_enc/hsv_enc',
and 'quantization' are set to the default values by the core, i.e. just
pass on the received format without conversion.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
---
 .../media/v4l/pixfmt-v4l2-mplane.rst          | 16 ++---
 .../userspace-api/media/v4l/pixfmt-v4l2.rst   | 64 +++++++++++++++++--
 .../media/v4l/vidioc-enum-fmt.rst             | 35 ++++++++++
 .../media/videodev2.h.rst.exceptions          |  5 ++
 include/uapi/linux/videodev2.h                |  6 ++
 5 files changed, 109 insertions(+), 17 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst b/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst
index 444b4082684c..66f3365d7b72 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-v4l2-mplane.rst
@@ -105,29 +105,21 @@ describing all planes of that format.
     * - __u8
       - ``ycbcr_enc``
       - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
-        This information supplements the ``colorspace`` and must be set by
-	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	See struct :c:type:`v4l2_pix_format`.
     * - __u8
       - ``hsv_enc``
       - HSV encoding, from enum :c:type:`v4l2_hsv_encoding`.
-        This information supplements the ``colorspace`` and must be set by
-	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	See struct :c:type:`v4l2_pix_format`.
     * - }
       -
     * - __u8
       - ``quantization``
       - Quantization range, from enum :c:type:`v4l2_quantization`.
-        This information supplements the ``colorspace`` and must be set by
-	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	See struct :c:type:`v4l2_pix_format`.
     * - __u8
       - ``xfer_func``
       - Transfer function, from enum :c:type:`v4l2_xfer_func`.
-        This information supplements the ``colorspace`` and must be set by
-	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	See struct :c:type:`v4l2_pix_format`.
     * - __u8
       - ``reserved[7]``
       - Reserved for future extensions. Should be zeroed by drivers and
diff --git a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
index 56a2952de873..c6d401605c0e 100644
--- a/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
+++ b/Documentation/userspace-api/media/v4l/pixfmt-v4l2.rst
@@ -116,7 +116,14 @@ Single-planar format structure
       - Image colorspace, from enum :c:type:`v4l2_colorspace`.
         This information supplements the ``pixelformat`` and must be set
 	by the driver for capture streams and by the application for
-	output streams, see :ref:`colorspaces`.
+	output streams, see :ref:`colorspaces`. If the application sets the
+	flag ``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific colorspace
+	for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported colorspace.
+	The driver indicates that colorspace conversion is supported by setting
+	the flag V4L2_FMT_FLAG_CSC_COLORSPACE in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
     * - __u32
       - ``priv``
       - This field indicates whether the remaining fields of the
@@ -153,13 +160,29 @@ Single-planar format structure
       - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
         This information supplements the ``colorspace`` and must be set by
 	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	streams, see :ref:`colorspaces`. If the application sets the
+	flag ``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific Y'CbCr encoding
+	for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported encoding.
+	This field is ignored for HSV pixelformats. The driver indicates that
+	ycbcr_enc conversion is supported by setting the flag
+	V4L2_FMT_FLAG_CSC_YCBCR_ENC in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
     * - __u32
       - ``hsv_enc``
       - HSV encoding, from enum :c:type:`v4l2_hsv_encoding`.
         This information supplements the ``colorspace`` and must be set by
 	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	streams, see :ref:`colorspaces`. If the application sets the flag
+	``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set this
+	field for a capture stream to request a specific HSV encoding for the
+	captured image data. If the driver cannot handle requested
+	conversion, it will return another supported encoding.
+	This field is ignored for non-HSV pixelformats. The driver indicates
+	that hsv_enc conversion is supported by setting the flag
+	V4L2_FMT_FLAG_CSC_HSV_ENC in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
     * - }
       -
     * - __u32
@@ -167,13 +190,27 @@ Single-planar format structure
       - Quantization range, from enum :c:type:`v4l2_quantization`.
         This information supplements the ``colorspace`` and must be set by
 	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	streams, see :ref:`colorspaces`. If the application sets the flag
+	``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific quantization
+	range for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported quantization.
+	The driver indicates that quantization conversion is supported by setting
+	the flag V4L2_FMT_FLAG_CSC_QUANTIZATION in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
     * - __u32
       - ``xfer_func``
       - Transfer function, from enum :c:type:`v4l2_xfer_func`.
         This information supplements the ``colorspace`` and must be set by
 	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	streams, see :ref:`colorspaces`. If the application sets the flag
+	``V4L2_PIX_FMT_FLAG_SET_CSC`` then the application can set
+	this field for a capture stream to request a specific transfer function
+	for the captured image data. If the driver cannot handle requested
+	conversion, it will return another supported transfer function.
+	The driver indicates that xfer_func conversion is supported by setting
+	the flag V4L2_FMT_FLAG_CSC_XFER_FUNC in the corresponding struct
+	:c:type:`v4l2_fmtdesc` during enumeration. See :ref:`fmtdesc-flags`.
 
 .. tabularcolumns:: |p{6.6cm}|p{2.2cm}|p{8.7cm}|
 
@@ -191,3 +228,20 @@ Single-planar format structure
 	by RGBA values (128, 192, 255, 128), the same pixel described with
 	premultiplied colors would be described by RGBA values (64, 96,
 	128, 128)
+    * .. _`v4l2-pix-fmt-flag-set-csc`:
+
+      - ``V4L2_PIX_FMT_FLAG_SET_CSC``
+      - 0x00000002
+      - Set by the application. It is only used for capture and is
+        ignored for output streams. If set, then request the device to do
+	colorspace conversion from the received colorspace to the requested
+	colorspace values. If the colorimetry field (``colorspace``, ``xfer_func``,
+	``ycbcr_enc``, ``hsv_enc`` or ``quantization``) is set to ``*_DEFAULT``,
+	then that colorimetry setting will remain unchanged from what was received.
+	So in order to change the quantization, only the ``quantization`` field shall
+	be set to non default value (``V4L2_QUANTIZATION_FULL_RANGE`` or
+	``V4L2_QUANTIZATION_LIM_RANGE``) and all other colorimetry fields shall
+	be set to ``*_DEFAULT``.
+
+	To check which conversions are supported by the hardware for the current
+	pixel format, see :ref:`fmtdesc-flags`.
diff --git a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
index 05835e04c20b..bae31c886b93 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-enum-fmt.rst
@@ -198,6 +198,41 @@ the ``mbus_code`` field is handled differently:
 	This flag can only be used in combination with the
 	``V4L2_FMT_FLAG_COMPRESSED`` flag, since this applies to
         compressed formats only. This flag is valid for stateful encoders only.
+    * - ``V4L2_FMT_FLAG_CSC_COLORSPACE``
+      - 0x0020
+      - The driver allows the application to try to change the default
+	colorspace. This flag is relevant only for capture devices.
+	The application can ask to configure the colorspace of the capture device
+	when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
+	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
+    * - ``V4L2_FMT_FLAG_CSC_XFER_FUNC``
+      - 0x0040
+      - The driver allows the application to try to change the default
+	transfer function. This flag is relevant only for capture devices.
+	The application can ask to configure the transfer function of the capture
+	device when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
+	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
+    * - ``V4L2_FMT_FLAG_CSC_YCBCR_ENC``
+      - 0x0080
+      - The driver allows the application to try to change the default
+	Y'CbCr encoding. This flag is relevant only for capture devices.
+	The application can ask to configure the Y'CbCr encoding of the capture device
+	when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
+	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
+    * - ``V4L2_FMT_FLAG_CSC_HSV_ENC``
+      - 0x0080
+      - The driver allows the application to try to change the default
+	HSV encoding. This flag is relevant only for capture devices.
+	The application can ask to configure the HSV encoding of the capture device
+	when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
+	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
+    * - ``V4L2_FMT_FLAG_CSC_QUANTIZATION``
+      - 0x0100
+      - The driver allows the application to try to change the default
+	quantization. This flag is relevant only for capture devices.
+	The application can ask to configure the quantization of the capture
+	device when calling the :ref:`VIDIOC_S_FMT <VIDIOC_G_FMT>` ioctl with
+	:ref:`V4L2_PIX_FMT_FLAG_SET_CSC <v4l2-pix-fmt-flag-set-csc>` set.
 
 
 Return Value
diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
index 659799cc1eca..121e396a2779 100644
--- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions
+++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions
@@ -188,6 +188,11 @@ replace define V4L2_FMT_FLAG_EMULATED fmtdesc-flags
 replace define V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM fmtdesc-flags
 replace define V4L2_FMT_FLAG_DYN_RESOLUTION fmtdesc-flags
 replace define V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL fmtdesc-flags
+replace define V4L2_FMT_FLAG_CSC_COLORSPACE fmtdesc-flags
+replace define V4L2_FMT_FLAG_CSC_XFER_FUNC fmtdesc-flags
+replace define V4L2_FMT_FLAG_CSC_YCBCR_ENC fmtdesc-flags
+replace define V4L2_FMT_FLAG_CSC_HSV_ENC fmtdesc-flags
+replace define V4L2_FMT_FLAG_CSC_QUANTIZATION fmtdesc-flags
 
 # V4L2 timecode types
 replace define V4L2_TC_TYPE_24FPS timecode-type
diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h
index c7b70ff53bc1..69c3e2077442 100644
--- a/include/uapi/linux/videodev2.h
+++ b/include/uapi/linux/videodev2.h
@@ -778,6 +778,7 @@ struct v4l2_pix_format {
 
 /* Flags */
 #define V4L2_PIX_FMT_FLAG_PREMUL_ALPHA	0x00000001
+#define V4L2_PIX_FMT_FLAG_SET_CSC	0x00000002
 
 /*
  *	F O R M A T   E N U M E R A T I O N
@@ -797,6 +798,11 @@ struct v4l2_fmtdesc {
 #define V4L2_FMT_FLAG_CONTINUOUS_BYTESTREAM	0x0004
 #define V4L2_FMT_FLAG_DYN_RESOLUTION		0x0008
 #define V4L2_FMT_FLAG_ENC_CAP_FRAME_INTERVAL	0x0010
+#define V4L2_FMT_FLAG_CSC_COLORSPACE		0x0020
+#define V4L2_FMT_FLAG_CSC_XFER_FUNC		0x0040
+#define V4L2_FMT_FLAG_CSC_YCBCR_ENC		0x0080
+#define V4L2_FMT_FLAG_CSC_HSV_ENC		V4L2_FMT_FLAG_CSC_YCBCR_ENC
+#define V4L2_FMT_FLAG_CSC_QUANTIZATION		0x0100
 
 	/* Frame Size and frame rate enumeration */
 /*
-- 
2.17.1

[PATCH v6 3/6] media: vivid: Add support to the CSC API

[Dafna Hirschfeld]

The CSC API (Colorspace conversion) allows userspace to try
to configure the colorspace, transfer function, Y'CbCr/HSV encoding
and the quantization for capture devices. This patch adds support
to the CSC API in vivid.
Using the CSC API, userspace is allowed to do the following:

- Set the colorspace.
- Set the xfer_func.
- Set the ycbcr_enc function for YUV formats.
- Set the hsv_enc function for HSV formats
- Set the quantization for YUV and RGB formats.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
---
 .../media/test-drivers/vivid/vivid-vid-cap.c  | 38 +++++++++++++++---
 .../test-drivers/vivid/vivid-vid-common.c     | 25 ++++++++++++
 include/media/v4l2-common.h                   | 39 +++++++++++++++++++
 3 files changed, 96 insertions(+), 6 deletions(-)

diff --git a/drivers/media/test-drivers/vivid/vivid-vid-cap.c b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
index e94beef008c8..eadf28ab1e39 100644
--- a/drivers/media/test-drivers/vivid/vivid-vid-cap.c
+++ b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
@@ -560,6 +560,7 @@ int vivid_try_fmt_vid_cap(struct file *file, void *priv,
 	unsigned factor = 1;
 	unsigned w, h;
 	unsigned p;
+	bool user_set_csc = !!(mp->flags & V4L2_PIX_FMT_FLAG_SET_CSC);
 
 	fmt = vivid_get_format(dev, mp->pixelformat);
 	if (!fmt) {
@@ -633,13 +634,30 @@ int vivid_try_fmt_vid_cap(struct file *file, void *priv,
 			(fmt->bit_depth[p] / fmt->vdownsampling[p])) /
 			(fmt->bit_depth[0] / fmt->vdownsampling[0]);
 
-	mp->colorspace = vivid_colorspace_cap(dev);
-	if (fmt->color_enc == TGP_COLOR_ENC_HSV)
-		mp->hsv_enc = vivid_hsv_enc_cap(dev);
-	else
+	if (!user_set_csc || !v4l2_is_colorspace_valid(mp->colorspace))
+		mp->colorspace = vivid_colorspace_cap(dev);
+
+	if (!user_set_csc || !v4l2_is_xfer_func_valid(mp->xfer_func))
+		mp->xfer_func = vivid_xfer_func_cap(dev);
+
+	if (fmt->color_enc == TGP_COLOR_ENC_HSV) {
+		if (!user_set_csc || !v4l2_is_hsv_enc_valid(mp->hsv_enc))
+			mp->hsv_enc = vivid_hsv_enc_cap(dev);
+	} else if (fmt->color_enc == TGP_COLOR_ENC_YCBCR) {
+		if (!user_set_csc || !v4l2_is_ycbcr_enc_valid(mp->ycbcr_enc))
+			mp->ycbcr_enc = vivid_ycbcr_enc_cap(dev);
+	} else {
 		mp->ycbcr_enc = vivid_ycbcr_enc_cap(dev);
-	mp->xfer_func = vivid_xfer_func_cap(dev);
-	mp->quantization = vivid_quantization_cap(dev);
+	}
+
+	if (fmt->color_enc == TGP_COLOR_ENC_YCBCR ||
+	    fmt->color_enc == TGP_COLOR_ENC_RGB) {
+		if (!user_set_csc || !v4l2_is_quant_valid(mp->quantization))
+			mp->quantization = vivid_quantization_cap(dev);
+	} else {
+		mp->quantization = vivid_quantization_cap(dev);
+	}
+
 	memset(mp->reserved, 0, sizeof(mp->reserved));
 	return 0;
 }
@@ -769,6 +787,14 @@ int vivid_s_fmt_vid_cap(struct file *file, void *priv,
 	if (vivid_is_sdtv_cap(dev))
 		dev->tv_field_cap = mp->field;
 	tpg_update_mv_step(&dev->tpg);
+	dev->tpg.colorspace = mp->colorspace;
+	dev->tpg.xfer_func = mp->xfer_func;
+	if (dev->fmt_cap->color_enc == TGP_COLOR_ENC_YCBCR)
+		dev->tpg.ycbcr_enc = mp->ycbcr_enc;
+	else
+		dev->tpg.hsv_enc = mp->hsv_enc;
+	dev->tpg.quantization = mp->quantization;
+
 	return 0;
 }
 
diff --git a/drivers/media/test-drivers/vivid/vivid-vid-common.c b/drivers/media/test-drivers/vivid/vivid-vid-common.c
index 76b0be670ebb..19701fe72030 100644
--- a/drivers/media/test-drivers/vivid/vivid-vid-common.c
+++ b/drivers/media/test-drivers/vivid/vivid-vid-common.c
@@ -920,6 +920,31 @@ int vivid_enum_fmt_vid(struct file *file, void  *priv,
 	fmt = &vivid_formats[f->index];
 
 	f->pixelformat = fmt->fourcc;
+
+	if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE &&
+	    f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
+		return 0;
+	/*
+	 * For capture devices, we support the CSC API.
+	 * We allow userspace to:
+	 * 1. set the colorspace
+	 * 2. set the xfer_func
+	 * 3. set the ycbcr_enc on YUV formats
+	 * 4. set the hsv_enc on HSV formats
+	 * 5. set the quantization on YUV and RGB formats
+	 */
+	f->flags |= V4L2_FMT_FLAG_CSC_COLORSPACE;
+	f->flags |= V4L2_FMT_FLAG_CSC_XFER_FUNC;
+
+	if (fmt->color_enc == TGP_COLOR_ENC_YCBCR) {
+		f->flags |= V4L2_FMT_FLAG_CSC_YCBCR_ENC;
+		f->flags |= V4L2_FMT_FLAG_CSC_QUANTIZATION;
+	} else if (fmt->color_enc == TGP_COLOR_ENC_HSV) {
+		f->flags |= V4L2_FMT_FLAG_CSC_HSV_ENC;
+	} else if (fmt->color_enc == TGP_COLOR_ENC_RGB) {
+		f->flags |= V4L2_FMT_FLAG_CSC_QUANTIZATION;
+	}
+
 	return 0;
 }
 
diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
index 150ee16ebd81..f024022d1909 100644
--- a/include/media/v4l2-common.h
+++ b/include/media/v4l2-common.h
@@ -539,4 +539,43 @@ static inline void v4l2_buffer_set_timestamp(struct v4l2_buffer *buf,
 	buf->timestamp.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
 }
 
+static inline bool v4l2_is_colorspace_valid(__u32 colorspace)
+{
+	if (colorspace > V4L2_COLORSPACE_DEFAULT &&
+	    colorspace <= V4L2_COLORSPACE_DCI_P3)
+		return true;
+	return false;
+}
+
+static inline bool v4l2_is_xfer_func_valid(__u32 xfer_func)
+{
+	if (xfer_func > V4L2_XFER_FUNC_DEFAULT &&
+	    xfer_func <= V4L2_XFER_FUNC_SMPTE2084)
+		return true;
+	return false;
+}
+
+static inline bool v4l2_is_ycbcr_enc_valid(__u8 ycbcr_enc)
+{
+	if (ycbcr_enc > V4L2_YCBCR_ENC_DEFAULT &&
+	    ycbcr_enc <= V4L2_YCBCR_ENC_SMPTE240M)
+		return true;
+	return false;
+}
+
+static inline bool v4l2_is_hsv_enc_valid(__u8 hsv_enc)
+{
+	if (hsv_enc == V4L2_HSV_ENC_180 || hsv_enc == V4L2_HSV_ENC_256)
+		return true;
+	return false;
+}
+
+static inline bool v4l2_is_quant_valid(__u8 quantization)
+{
+	if (quantization == V4L2_QUANTIZATION_FULL_RANGE ||
+	    quantization == V4L2_QUANTIZATION_LIM_RANGE)
+		return true;
+	return false;
+}
+
 #endif /* V4L2_COMMON_H_ */
-- 
2.17.1

[PATCH v6 4/6] v4l2: extend the CSC API to subdevice.

[Dafna Hirschfeld]

This patch extends the CSC API in video devices to be supported
also on sub-devices. The flag V4L2_MBUS_FRAMEFMT_SET_CSC set by
the application when calling VIDIOC_SUBDEV_S_FMT ioctl.
The flags:

V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE,
V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC,
V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC/V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION

are set by the driver in the VIDIOC_SUBDEV_ENUM_MBUS_CODE ioctl.

New 'flags' fields were added to the structs
v4l2_subdev_mbus_code_enum, v4l2_mbus_framefmt which are borrowed
from the 'reserved' field

The patch also replaces the 'ycbcr_enc' field in
'struct v4l2_mbus_framefmt' with a union that includes 'hsv_enc'

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
---
 .../media/v4l/subdev-formats.rst              | 98 +++++++++++++++++--
 .../v4l/vidioc-subdev-enum-mbus-code.rst      | 51 +++++++++-
 include/uapi/linux/v4l2-mediabus.h            | 17 +++-
 include/uapi/linux/v4l2-subdev.h              |  9 +-
 4 files changed, 161 insertions(+), 14 deletions(-)

diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst
index 9a4d61b0d76f..6495bf183896 100644
--- a/Documentation/userspace-api/media/v4l/subdev-formats.rst
+++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst
@@ -41,32 +41,110 @@ Media Bus Formats
 	:ref:`field-order` for details.
     * - __u32
       - ``colorspace``
-      - Image colorspace, from enum
-	:c:type:`v4l2_colorspace`. See
-	:ref:`colorspaces` for details.
+      - Image colorspace, from enum :c:type:`v4l2_colorspace`.
+        Must be set by the driver for subdevices. If the application sets the
+	flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set this
+	field on the source pad to request a specific colorspace for the media
+	bus data. If the driver cannot handle the requested conversion, it will
+	return another supported colorspace. The driver indicates that colorspace
+	conversion is supported by setting the flag
+	V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE in the corresponding struct
+	:c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
+	See :ref:`v4l2-subdev-mbus-code-flags`.
+    * - union {
+      - (anonymous)
     * - __u16
       - ``ycbcr_enc``
       - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
         This information supplements the ``colorspace`` and must be set by
-	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	the driver for subdevices, see :ref:`colorspaces`. If the application
+	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
+	this field on a source pad to request a specific Y'CbCr encoding
+	for the media bus data. If the driver cannot handle the requested
+	conversion, it will return another supported encoding.
+	This field is ignored for HSV media bus formats. The driver indicates
+	that ycbcr_enc conversion is supported by setting the flag
+	V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC in the corresponding struct
+	:c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
+	See :ref:`v4l2-subdev-mbus-code-flags`.
+    * - __u16
+      - ``hsv_enc``
+      - HSV encoding, from enum :c:type:`v4l2_hsv_encoding`.
+        This information supplements the ``colorspace`` and must be set by
+	the driver for subdevices, see :ref:`colorspaces`. If the application
+	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
+	this field on a source pad to request a specific HSV encoding
+	for the media bus data. If the driver cannot handle the requested
+	conversion, it will return another supported encoding.
+	This field is ignored for Y'CbCr media bus formats. The driver indicates
+	that hsv_enc conversion is supported by setting the flag
+	V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC in the corresponding struct
+	:c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
+	See :ref:`v4l2-subdev-mbus-code-flags`
+    * - }
+      -
     * - __u16
       - ``quantization``
       - Quantization range, from enum :c:type:`v4l2_quantization`.
         This information supplements the ``colorspace`` and must be set by
-	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	the driver for subdevices, see :ref:`colorspaces`. If the application
+	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
+	this field on a source pad to request a specific quantization
+	for the media bus data. If the driver cannot handle the requested
+	conversion, it will return another supported quantization.
+	The driver indicates that quantization conversion is supported by
+	setting the flag V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION in the
+	corresponding struct :c:type:`v4l2_subdev_mbus_code_enum`
+	during enumeration. See :ref:`v4l2-subdev-mbus-code-flags`.
+
     * - __u16
       - ``xfer_func``
       - Transfer function, from enum :c:type:`v4l2_xfer_func`.
         This information supplements the ``colorspace`` and must be set by
-	the driver for capture streams and by the application for output
-	streams, see :ref:`colorspaces`.
+	the driver for subdevices, see :ref:`colorspaces`. If the application
+	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
+	this field on a source pad to request a specific transfer
+	function for the media bus data. If the driver cannot handle the requested
+	conversion, it will return another supported transfer function.
+	The driver indicates that the transfer function conversion is supported by
+	setting the flag V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC in the
+	corresponding struct :c:type:`v4l2_subdev_mbus_code_enum`
+	during enumeration. See :ref:`v4l2-subdev-mbus-code-flags`.
     * - __u16
-      - ``reserved``\ [11]
+      - ``reserved2``
+      - Reserved for future extensions.
+    * - __u32
+      - ``flags``
+      - flags See:  :ref:v4l2-mbus-framefmt-flags
+    * - __u16
+      - ``reserved``\ [8]
       - Reserved for future extensions. Applications and drivers must set
 	the array to zero.
 
+.. _v4l2-mbus-framefmt-flags:
+
+.. flat-table:: v4l2_mbus_framefmt Flags
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       3 1 4
+
+    * .. _`mbus-framefmt-set-csc`:
+
+      - ``V4L2_MBUS_FRAMEFMT_SET_CSC``
+      - 0x00000001
+      - Set by the application. It is only used for source pads and is
+	ignored for sink pads. If set, then request the subdevice to do
+	colorspace conversion from the received colorspace to the requested
+	colorspace values. If the colorimetry field (``colorspace``, ``xfer_func``,
+	``ycbcr_enc``, ``hsv_enc`` or ``quantization``) is set to ``*_DEFAULT``,
+	then that colorimetry setting will remain unchanged from what was received.
+	So in order to change the quantization, only the ``quantization`` field shall
+	be set to non default value (``V4L2_QUANTIZATION_FULL_RANGE`` or
+	``V4L2_QUANTIZATION_LIM_RANGE``) and all other colorimetry fields shall
+	be set to ``*_DEFAULT``.
+
+	To check which conversions are supported by the hardware for the current
+	media bus frame format, see :ref:`v4l2-subdev-mbus-code-flags`.
 
 
 .. _v4l2-mbus-pixelcode:
diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
index 35b8607203a4..d9bb12ac2145 100644
--- a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
+++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
@@ -79,11 +79,60 @@ information about the try formats.
       - Media bus format codes to be enumerated, from enum
 	:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
     * - __u32
-      - ``reserved``\ [8]
+      - ``flags``
+      - See :ref:`v4l2-subdev-mbus-code-flags`
+    * - __u32
+      - ``reserved``\ [7]
       - Reserved for future extensions. Applications and drivers must set
 	the array to zero.
 
 
+
+.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{7.7cm}|
+
+.. _v4l2-subdev-mbus-code-flags:
+
+.. flat-table:: Subdev Media Bus Code Enumerate Flags
+    :header-rows:  0
+    :stub-columns: 0
+    :widths:       1 1 2
+
+    * - V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE
+      - 0x00000001
+      - The driver allows the application to try to change the default colorspace
+	encoding. The application can ask to configure the colorspace of the
+	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
+	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
+	See :ref:`v4l2-mbus-format` on how to do this.
+    * - V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC
+      - 0x00000002
+      - The driver allows the application to try to change the default transform function.
+	The application can ask to configure the transform function of
+	the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
+	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
+	See :ref:`v4l2-mbus-format` on how to do this.
+    * - V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
+      - 0x00000004
+      - The driver allows the application to try to change the default Y'CbCr
+	encoding. The application can ask to configure the Y'CbCr encoding of the
+	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
+	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
+	See :ref:`v4l2-mbus-format` on how to do this.
+    * - V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
+      - 0x00000004
+      - The driver allows the application to try to change the default HSV
+	encoding. The application can ask to configure the HSV encoding of the
+	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
+	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
+	See :ref:`v4l2-mbus-format` on how to do this.
+    * - V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
+      - 0x00000008
+      - The driver allows the application to try to change the default
+	quantization. The application can ask to configure the quantization of
+	the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
+	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
+	See :ref:`v4l2-mbus-format` on how to do this.
+
 Return Value
 ============
 
diff --git a/include/uapi/linux/v4l2-mediabus.h b/include/uapi/linux/v4l2-mediabus.h
index 123a231001a8..d0bc8df18ad5 100644
--- a/include/uapi/linux/v4l2-mediabus.h
+++ b/include/uapi/linux/v4l2-mediabus.h
@@ -16,6 +16,8 @@
 #include <linux/types.h>
 #include <linux/videodev2.h>
 
+#define V4L2_MBUS_FRAMEFMT_SET_CSC	0x00000001
+
 /**
  * struct v4l2_mbus_framefmt - frame format on the media bus
  * @width:	image width
@@ -24,8 +26,12 @@
  * @field:	used interlacing type (from enum v4l2_field)
  * @colorspace:	colorspace of the data (from enum v4l2_colorspace)
  * @ycbcr_enc:	YCbCr encoding of the data (from enum v4l2_ycbcr_encoding)
+ * @hsv_enc:	HSV encoding of the data (from enum v4l2_hsv_encoding)
  * @quantization: quantization of the data (from enum v4l2_quantization)
  * @xfer_func:  transfer function of the data (from enum v4l2_xfer_func)
+ * @reserved2:  two reserved bytes that can be later used
+ * @flags:	flags (V4L2_MBUS_FRAMEFMT_*)
+ * @reserved:  reserved bytes that can be later used
  */
 struct v4l2_mbus_framefmt {
 	__u32			width;
@@ -33,10 +39,17 @@ struct v4l2_mbus_framefmt {
 	__u32			code;
 	__u32			field;
 	__u32			colorspace;
-	__u16			ycbcr_enc;
+	union {
+		/* enum v4l2_ycbcr_encoding */
+		__u16			ycbcr_enc;
+		/* enum v4l2_hsv_encoding */
+		__u16			hsv_enc;
+	};
 	__u16			quantization;
 	__u16			xfer_func;
-	__u16			reserved[11];
+	__u16			reserved2;
+	__u32			flags;
+	__u16			reserved[8];
 };
 
 #ifndef __KERNEL__
diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
index 5d2a1dab7911..e93970a2a38f 100644
--- a/include/uapi/linux/v4l2-subdev.h
+++ b/include/uapi/linux/v4l2-subdev.h
@@ -65,19 +65,26 @@ struct v4l2_subdev_crop {
 	__u32 reserved[8];
 };
 
+#define V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE	0x00000001
+#define V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC	0x00000002
+#define V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC	0x00000004
+#define V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC	V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
+#define V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION	0x00000008
 /**
  * struct v4l2_subdev_mbus_code_enum - Media bus format enumeration
  * @pad: pad number, as reported by the media API
  * @index: format index during enumeration
  * @code: format code (MEDIA_BUS_FMT_ definitions)
  * @which: format type (from enum v4l2_subdev_format_whence)
+ * @flags: flags set by the driver, (V4L2_SUBDEV_MBUS_CODE_*)
  */
 struct v4l2_subdev_mbus_code_enum {
 	__u32 pad;
 	__u32 index;
 	__u32 code;
 	__u32 which;
-	__u32 reserved[8];
+	__u32 flags;
+	__u32 reserved[7];
 };
 
 /**
-- 
2.17.1

[PATCH v6 5/6] media: staging: rkisp1: allow quantization setting by userspace on the isp source pad

[Dafna Hirschfeld]

The isp entity has hardware support to force full range quantization
for YUV formats. Use the subdev CSC API to allow userspace to set the
quantization for YUV formats on the isp entity.

- The flag V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION is set for
YUV formats during enumeration of the isp formats on the source pad.
- The full quantization is set on YUV formats if userspace asks it
on the isp entity using the flag V4L2_MBUS_FRAMEFMT_SET_CSC.

On the capture and the resizer, the quantization is read-only
and always set to the default quantization.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: Helen Koike <helen.koike@collabora.com>
Reviewed-by: Tomasz Figa <tfiga@chromium.org>
---
 drivers/staging/media/rkisp1/TODO             |  2 +-
 drivers/staging/media/rkisp1/rkisp1-capture.c | 10 ----------
 drivers/staging/media/rkisp1/rkisp1-isp.c     | 20 +++++++++++++++----
 3 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/drivers/staging/media/rkisp1/TODO b/drivers/staging/media/rkisp1/TODO
index bdb1b8f73556..bdd1da43cb5e 100644
--- a/drivers/staging/media/rkisp1/TODO
+++ b/drivers/staging/media/rkisp1/TODO
@@ -1,7 +1,7 @@
 * Fix pad format size for statistics and parameters entities.
 * Fix checkpatch errors.
 * Review and comment every lock
-* Handle quantization
+* Add uapi docs. Remember to add documentation of how quantization is handled.
 * Document rkisp1-common.h
 * streaming paths (mainpath and selfpath) check if the other path is streaming
 in several places of the code, review this, specially that it doesn't seem it
diff --git a/drivers/staging/media/rkisp1/rkisp1-capture.c b/drivers/staging/media/rkisp1/rkisp1-capture.c
index c05280950ea0..f355b2977009 100644
--- a/drivers/staging/media/rkisp1/rkisp1-capture.c
+++ b/drivers/staging/media/rkisp1/rkisp1-capture.c
@@ -1069,8 +1069,6 @@ static void rkisp1_try_fmt(const struct rkisp1_capture *cap,
 			   const struct v4l2_format_info **fmt_info)
 {
 	const struct rkisp1_capture_config *config = cap->config;
-	struct rkisp1_capture *other_cap =
-			&cap->rkisp1->capture_devs[cap->id ^ 1];
 	const struct rkisp1_capture_fmt_cfg *fmt;
 	const struct v4l2_format_info *info;
 	const unsigned int max_widths[] = { RKISP1_RSZ_MP_SRC_MAX_WIDTH,
@@ -1095,14 +1093,6 @@ static void rkisp1_try_fmt(const struct rkisp1_capture *cap,
 
 	info = rkisp1_fill_pixfmt(pixm, cap->id);
 
-	/* can not change quantization when stream-on */
-	if (other_cap->is_streaming)
-		pixm->quantization = other_cap->pix.fmt.quantization;
-	/* output full range by default, take effect in params */
-	else if (!pixm->quantization ||
-		 pixm->quantization > V4L2_QUANTIZATION_LIM_RANGE)
-		pixm->quantization = V4L2_QUANTIZATION_FULL_RANGE;
-
 	if (fmt_cfg)
 		*fmt_cfg = fmt;
 	if (fmt_info)
diff --git a/drivers/staging/media/rkisp1/rkisp1-isp.c b/drivers/staging/media/rkisp1/rkisp1-isp.c
index 6ec1e9816e9f..1063f4505aaf 100644
--- a/drivers/staging/media/rkisp1/rkisp1-isp.c
+++ b/drivers/staging/media/rkisp1/rkisp1-isp.c
@@ -589,6 +589,10 @@ static int rkisp1_isp_enum_mbus_code(struct v4l2_subdev *sd,
 
 		if (code->index == pos - 1) {
 			code->code = fmt->mbus_code;
+			if (fmt->pixel_enc == V4L2_PIXEL_ENC_YUV &&
+			    dir == RKISP1_ISP_SD_SRC)
+				code->flags =
+					V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION;
 			return 0;
 		}
 	}
@@ -620,7 +624,6 @@ static int rkisp1_isp_init_config(struct v4l2_subdev *sd,
 					     RKISP1_ISP_PAD_SOURCE_VIDEO);
 	*src_fmt = *sink_fmt;
 	src_fmt->code = RKISP1_DEF_SRC_PAD_FMT;
-	src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
 
 	src_crop = v4l2_subdev_get_try_crop(sd, cfg,
 					    RKISP1_ISP_PAD_SOURCE_VIDEO);
@@ -663,9 +666,18 @@ static void rkisp1_isp_set_src_fmt(struct rkisp1_isp *isp,
 		isp->src_fmt = mbus_info;
 	src_fmt->width  = src_crop->width;
 	src_fmt->height = src_crop->height;
-	src_fmt->quantization = format->quantization;
-	/* full range by default */
-	if (!src_fmt->quantization)
+
+	/*
+	 * The CSC API is used to allow userspace to force full
+	 * quantization on YUV formats.
+	 */
+	if (format->flags & V4L2_MBUS_FRAMEFMT_SET_CSC &&
+	    format->quantization == V4L2_QUANTIZATION_FULL_RANGE &&
+	    mbus_info->pixel_enc == V4L2_PIXEL_ENC_YUV)
+		src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
+	else if (mbus_info->pixel_enc == V4L2_PIXEL_ENC_YUV)
+		src_fmt->quantization = V4L2_QUANTIZATION_LIM_RANGE;
+	else
 		src_fmt->quantization = V4L2_QUANTIZATION_FULL_RANGE;
 
 	*format = *src_fmt;
-- 
2.17.1

[PATCH v6 6/6] media: staging: rkisp1: rsz: set flags to 0 in enum_mbus_code cb

[Dafna Hirschfeld]

The resizer calls the enum_mbus_code cb on the source pad of
the isp entity since they support the same formats.
The only difference is that the isp entity allows setting the
quantization and sets the flag V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION.
The resizer should therefore set the flags to 0.

Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
---
 drivers/staging/media/rkisp1/rkisp1-resizer.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/staging/media/rkisp1/rkisp1-resizer.c b/drivers/staging/media/rkisp1/rkisp1-resizer.c
index c66d2a52fd71..155e0817f3a6 100644
--- a/drivers/staging/media/rkisp1/rkisp1-resizer.c
+++ b/drivers/staging/media/rkisp1/rkisp1-resizer.c
@@ -444,6 +444,7 @@ static int rkisp1_rsz_enum_mbus_code(struct v4l2_subdev *sd,
 
 	/* restore pad */
 	code->pad = pad;
+	code->flags = 0;
 	return ret;
 }
 
-- 
2.17.1

Re: [PATCH v6 3/6] media: vivid: Add support to the CSC API

[Hans Verkuil]

On 18/08/2020 10:18, Dafna Hirschfeld wrote:
> The CSC API (Colorspace conversion) allows userspace to try
> to configure the colorspace, transfer function, Y'CbCr/HSV encoding
> and the quantization for capture devices. This patch adds support
> to the CSC API in vivid.
> Using the CSC API, userspace is allowed to do the following:
> 
> - Set the colorspace.
> - Set the xfer_func.
> - Set the ycbcr_enc function for YUV formats.
> - Set the hsv_enc function for HSV formats
> - Set the quantization for YUV and RGB formats.
> 
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> ---
>  .../media/test-drivers/vivid/vivid-vid-cap.c  | 38 +++++++++++++++---
>  .../test-drivers/vivid/vivid-vid-common.c     | 25 ++++++++++++
>  include/media/v4l2-common.h                   | 39 +++++++++++++++++++
>  3 files changed, 96 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/test-drivers/vivid/vivid-vid-cap.c b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
> index e94beef008c8..eadf28ab1e39 100644
> --- a/drivers/media/test-drivers/vivid/vivid-vid-cap.c
> +++ b/drivers/media/test-drivers/vivid/vivid-vid-cap.c
> @@ -560,6 +560,7 @@ int vivid_try_fmt_vid_cap(struct file *file, void *priv,
>  	unsigned factor = 1;
>  	unsigned w, h;
>  	unsigned p;
> +	bool user_set_csc = !!(mp->flags & V4L2_PIX_FMT_FLAG_SET_CSC);
>  
>  	fmt = vivid_get_format(dev, mp->pixelformat);
>  	if (!fmt) {
> @@ -633,13 +634,30 @@ int vivid_try_fmt_vid_cap(struct file *file, void *priv,
>  			(fmt->bit_depth[p] / fmt->vdownsampling[p])) /
>  			(fmt->bit_depth[0] / fmt->vdownsampling[0]);
>  
> -	mp->colorspace = vivid_colorspace_cap(dev);
> -	if (fmt->color_enc == TGP_COLOR_ENC_HSV)
> -		mp->hsv_enc = vivid_hsv_enc_cap(dev);
> -	else
> +	if (!user_set_csc || !v4l2_is_colorspace_valid(mp->colorspace))
> +		mp->colorspace = vivid_colorspace_cap(dev);
> +
> +	if (!user_set_csc || !v4l2_is_xfer_func_valid(mp->xfer_func))
> +		mp->xfer_func = vivid_xfer_func_cap(dev);
> +
> +	if (fmt->color_enc == TGP_COLOR_ENC_HSV) {
> +		if (!user_set_csc || !v4l2_is_hsv_enc_valid(mp->hsv_enc))
> +			mp->hsv_enc = vivid_hsv_enc_cap(dev);
> +	} else if (fmt->color_enc == TGP_COLOR_ENC_YCBCR) {
> +		if (!user_set_csc || !v4l2_is_ycbcr_enc_valid(mp->ycbcr_enc))
> +			mp->ycbcr_enc = vivid_ycbcr_enc_cap(dev);
> +	} else {
>  		mp->ycbcr_enc = vivid_ycbcr_enc_cap(dev);
> -	mp->xfer_func = vivid_xfer_func_cap(dev);
> -	mp->quantization = vivid_quantization_cap(dev);
> +	}
> +
> +	if (fmt->color_enc == TGP_COLOR_ENC_YCBCR ||
> +	    fmt->color_enc == TGP_COLOR_ENC_RGB) {
> +		if (!user_set_csc || !v4l2_is_quant_valid(mp->quantization))
> +			mp->quantization = vivid_quantization_cap(dev);
> +	} else {
> +		mp->quantization = vivid_quantization_cap(dev);
> +	}
> +
>  	memset(mp->reserved, 0, sizeof(mp->reserved));
>  	return 0;
>  }
> @@ -769,6 +787,14 @@ int vivid_s_fmt_vid_cap(struct file *file, void *priv,
>  	if (vivid_is_sdtv_cap(dev))
>  		dev->tv_field_cap = mp->field;
>  	tpg_update_mv_step(&dev->tpg);
> +	dev->tpg.colorspace = mp->colorspace;
> +	dev->tpg.xfer_func = mp->xfer_func;
> +	if (dev->fmt_cap->color_enc == TGP_COLOR_ENC_YCBCR)
> +		dev->tpg.ycbcr_enc = mp->ycbcr_enc;
> +	else
> +		dev->tpg.hsv_enc = mp->hsv_enc;
> +	dev->tpg.quantization = mp->quantization;
> +
>  	return 0;
>  }
>  
> diff --git a/drivers/media/test-drivers/vivid/vivid-vid-common.c b/drivers/media/test-drivers/vivid/vivid-vid-common.c
> index 76b0be670ebb..19701fe72030 100644
> --- a/drivers/media/test-drivers/vivid/vivid-vid-common.c
> +++ b/drivers/media/test-drivers/vivid/vivid-vid-common.c
> @@ -920,6 +920,31 @@ int vivid_enum_fmt_vid(struct file *file, void  *priv,
>  	fmt = &vivid_formats[f->index];
>  
>  	f->pixelformat = fmt->fourcc;
> +
> +	if (f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE &&
> +	    f->type != V4L2_BUF_TYPE_VIDEO_CAPTURE_MPLANE)
> +		return 0;
> +	/*
> +	 * For capture devices, we support the CSC API.
> +	 * We allow userspace to:
> +	 * 1. set the colorspace
> +	 * 2. set the xfer_func
> +	 * 3. set the ycbcr_enc on YUV formats
> +	 * 4. set the hsv_enc on HSV formats
> +	 * 5. set the quantization on YUV and RGB formats
> +	 */
> +	f->flags |= V4L2_FMT_FLAG_CSC_COLORSPACE;
> +	f->flags |= V4L2_FMT_FLAG_CSC_XFER_FUNC;
> +
> +	if (fmt->color_enc == TGP_COLOR_ENC_YCBCR) {
> +		f->flags |= V4L2_FMT_FLAG_CSC_YCBCR_ENC;
> +		f->flags |= V4L2_FMT_FLAG_CSC_QUANTIZATION;
> +	} else if (fmt->color_enc == TGP_COLOR_ENC_HSV) {
> +		f->flags |= V4L2_FMT_FLAG_CSC_HSV_ENC;
> +	} else if (fmt->color_enc == TGP_COLOR_ENC_RGB) {
> +		f->flags |= V4L2_FMT_FLAG_CSC_QUANTIZATION;
> +	}
> +
>  	return 0;
>  }
>  
> diff --git a/include/media/v4l2-common.h b/include/media/v4l2-common.h
> index 150ee16ebd81..f024022d1909 100644
> --- a/include/media/v4l2-common.h
> +++ b/include/media/v4l2-common.h
> @@ -539,4 +539,43 @@ static inline void v4l2_buffer_set_timestamp(struct v4l2_buffer *buf,
>  	buf->timestamp.tv_usec = ts.tv_nsec / NSEC_PER_USEC;
>  }
>  
> +static inline bool v4l2_is_colorspace_valid(__u32 colorspace)
> +{
> +	if (colorspace > V4L2_COLORSPACE_DEFAULT &&
> +	    colorspace <= V4L2_COLORSPACE_DCI_P3)
> +		return true;
> +	return false;

Just simplify this and the others below to:

	return colorspace > V4L2_COLORSPACE_DEFAULT &&
	       colorspace <= V4L2_COLORSPACE_DCI_P3;

Regards,

	Hans

> +}
> +
> +static inline bool v4l2_is_xfer_func_valid(__u32 xfer_func)
> +{
> +	if (xfer_func > V4L2_XFER_FUNC_DEFAULT &&
> +	    xfer_func <= V4L2_XFER_FUNC_SMPTE2084)
> +		return true;
> +	return false;
> +}
> +
> +static inline bool v4l2_is_ycbcr_enc_valid(__u8 ycbcr_enc)
> +{
> +	if (ycbcr_enc > V4L2_YCBCR_ENC_DEFAULT &&
> +	    ycbcr_enc <= V4L2_YCBCR_ENC_SMPTE240M)
> +		return true;
> +	return false;
> +}
> +
> +static inline bool v4l2_is_hsv_enc_valid(__u8 hsv_enc)
> +{
> +	if (hsv_enc == V4L2_HSV_ENC_180 || hsv_enc == V4L2_HSV_ENC_256)
> +		return true;
> +	return false;
> +}
> +
> +static inline bool v4l2_is_quant_valid(__u8 quantization)
> +{
> +	if (quantization == V4L2_QUANTIZATION_FULL_RANGE ||
> +	    quantization == V4L2_QUANTIZATION_LIM_RANGE)
> +		return true;
> +	return false;
> +}
> +
>  #endif /* V4L2_COMMON_H_ */
> 

Re: [PATCH v6 4/6] v4l2: extend the CSC API to subdevice.

[Hans Verkuil]

On 18/08/2020 10:18, Dafna Hirschfeld wrote:
> This patch extends the CSC API in video devices to be supported
> also on sub-devices. The flag V4L2_MBUS_FRAMEFMT_SET_CSC set by
> the application when calling VIDIOC_SUBDEV_S_FMT ioctl.
> The flags:
> 
> V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE,
> V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC,
> V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC/V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
> V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
> 
> are set by the driver in the VIDIOC_SUBDEV_ENUM_MBUS_CODE ioctl.
> 
> New 'flags' fields were added to the structs
> v4l2_subdev_mbus_code_enum, v4l2_mbus_framefmt which are borrowed
> from the 'reserved' field
> 
> The patch also replaces the 'ycbcr_enc' field in
> 'struct v4l2_mbus_framefmt' with a union that includes 'hsv_enc'
> 
> Signed-off-by: Dafna Hirschfeld <dafna.hirschfeld@collabora.com>
> ---
>  .../media/v4l/subdev-formats.rst              | 98 +++++++++++++++++--
>  .../v4l/vidioc-subdev-enum-mbus-code.rst      | 51 +++++++++-
>  include/uapi/linux/v4l2-mediabus.h            | 17 +++-
>  include/uapi/linux/v4l2-subdev.h              |  9 +-
>  4 files changed, 161 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/userspace-api/media/v4l/subdev-formats.rst b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> index 9a4d61b0d76f..6495bf183896 100644
> --- a/Documentation/userspace-api/media/v4l/subdev-formats.rst
> +++ b/Documentation/userspace-api/media/v4l/subdev-formats.rst
> @@ -41,32 +41,110 @@ Media Bus Formats
>  	:ref:`field-order` for details.
>      * - __u32
>        - ``colorspace``
> -      - Image colorspace, from enum
> -	:c:type:`v4l2_colorspace`. See
> -	:ref:`colorspaces` for details.
> +      - Image colorspace, from enum :c:type:`v4l2_colorspace`.
> +        Must be set by the driver for subdevices. If the application sets the
> +	flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set this
> +	field on the source pad to request a specific colorspace for the media
> +	bus data. If the driver cannot handle the requested conversion, it will
> +	return another supported colorspace. The driver indicates that colorspace
> +	conversion is supported by setting the flag
> +	V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE in the corresponding struct
> +	:c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
> +	See :ref:`v4l2-subdev-mbus-code-flags`.
> +    * - union {
> +      - (anonymous)
>      * - __u16
>        - ``ycbcr_enc``
>        - Y'CbCr encoding, from enum :c:type:`v4l2_ycbcr_encoding`.
>          This information supplements the ``colorspace`` and must be set by
> -	the driver for capture streams and by the application for output
> -	streams, see :ref:`colorspaces`.
> +	the driver for subdevices, see :ref:`colorspaces`. If the application
> +	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
> +	this field on a source pad to request a specific Y'CbCr encoding
> +	for the media bus data. If the driver cannot handle the requested
> +	conversion, it will return another supported encoding.
> +	This field is ignored for HSV media bus formats. The driver indicates
> +	that ycbcr_enc conversion is supported by setting the flag
> +	V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC in the corresponding struct
> +	:c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
> +	See :ref:`v4l2-subdev-mbus-code-flags`.
> +    * - __u16
> +      - ``hsv_enc``
> +      - HSV encoding, from enum :c:type:`v4l2_hsv_encoding`.
> +        This information supplements the ``colorspace`` and must be set by
> +	the driver for subdevices, see :ref:`colorspaces`. If the application
> +	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
> +	this field on a source pad to request a specific HSV encoding
> +	for the media bus data. If the driver cannot handle the requested
> +	conversion, it will return another supported encoding.
> +	This field is ignored for Y'CbCr media bus formats. The driver indicates
> +	that hsv_enc conversion is supported by setting the flag
> +	V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC in the corresponding struct
> +	:c:type:`v4l2_subdev_mbus_code_enum` during enumeration.
> +	See :ref:`v4l2-subdev-mbus-code-flags`
> +    * - }
> +      -
>      * - __u16
>        - ``quantization``
>        - Quantization range, from enum :c:type:`v4l2_quantization`.
>          This information supplements the ``colorspace`` and must be set by
> -	the driver for capture streams and by the application for output
> -	streams, see :ref:`colorspaces`.
> +	the driver for subdevices, see :ref:`colorspaces`. If the application
> +	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
> +	this field on a source pad to request a specific quantization
> +	for the media bus data. If the driver cannot handle the requested
> +	conversion, it will return another supported quantization.
> +	The driver indicates that quantization conversion is supported by
> +	setting the flag V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION in the
> +	corresponding struct :c:type:`v4l2_subdev_mbus_code_enum`
> +	during enumeration. See :ref:`v4l2-subdev-mbus-code-flags`.
> +
>      * - __u16
>        - ``xfer_func``
>        - Transfer function, from enum :c:type:`v4l2_xfer_func`.
>          This information supplements the ``colorspace`` and must be set by
> -	the driver for capture streams and by the application for output
> -	streams, see :ref:`colorspaces`.
> +	the driver for subdevices, see :ref:`colorspaces`. If the application
> +	sets the flag ``V4L2_MBUS_FRAMEFMT_SET_CSC`` then the application can set
> +	this field on a source pad to request a specific transfer
> +	function for the media bus data. If the driver cannot handle the requested
> +	conversion, it will return another supported transfer function.
> +	The driver indicates that the transfer function conversion is supported by
> +	setting the flag V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC in the
> +	corresponding struct :c:type:`v4l2_subdev_mbus_code_enum`
> +	during enumeration. See :ref:`v4l2-subdev-mbus-code-flags`.
>      * - __u16
> -      - ``reserved``\ [11]
> +      - ``reserved2``
> +      - Reserved for future extensions.
> +    * - __u32
> +      - ``flags``
> +      - flags See:  :ref:v4l2-mbus-framefmt-flags
> +    * - __u16
> +      - ``reserved``\ [8]
>        - Reserved for future extensions. Applications and drivers must set
>  	the array to zero.
>  
> +.. _v4l2-mbus-framefmt-flags:
> +
> +.. flat-table:: v4l2_mbus_framefmt Flags
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       3 1 4
> +
> +    * .. _`mbus-framefmt-set-csc`:
> +
> +      - ``V4L2_MBUS_FRAMEFMT_SET_CSC``
> +      - 0x00000001
> +      - Set by the application. It is only used for source pads and is
> +	ignored for sink pads. If set, then request the subdevice to do
> +	colorspace conversion from the received colorspace to the requested
> +	colorspace values. If the colorimetry field (``colorspace``, ``xfer_func``,
> +	``ycbcr_enc``, ``hsv_enc`` or ``quantization``) is set to ``*_DEFAULT``,
> +	then that colorimetry setting will remain unchanged from what was received.
> +	So in order to change the quantization, only the ``quantization`` field shall
> +	be set to non default value (``V4L2_QUANTIZATION_FULL_RANGE`` or
> +	``V4L2_QUANTIZATION_LIM_RANGE``) and all other colorimetry fields shall
> +	be set to ``*_DEFAULT``.
> +
> +	To check which conversions are supported by the hardware for the current
> +	media bus frame format, see :ref:`v4l2-subdev-mbus-code-flags`.
>  
>  
>  .. _v4l2-mbus-pixelcode:
> diff --git a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
> index 35b8607203a4..d9bb12ac2145 100644
> --- a/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
> +++ b/Documentation/userspace-api/media/v4l/vidioc-subdev-enum-mbus-code.rst
> @@ -79,11 +79,60 @@ information about the try formats.
>        - Media bus format codes to be enumerated, from enum
>  	:ref:`v4l2_subdev_format_whence <v4l2-subdev-format-whence>`.
>      * - __u32
> -      - ``reserved``\ [8]
> +      - ``flags``
> +      - See :ref:`v4l2-subdev-mbus-code-flags`
> +    * - __u32
> +      - ``reserved``\ [7]
>        - Reserved for future extensions. Applications and drivers must set
>  	the array to zero.
>  
>  
> +
> +.. tabularcolumns:: |p{4.4cm}|p{4.4cm}|p{7.7cm}|
> +
> +.. _v4l2-subdev-mbus-code-flags:
> +
> +.. flat-table:: Subdev Media Bus Code Enumerate Flags
> +    :header-rows:  0
> +    :stub-columns: 0
> +    :widths:       1 1 2
> +
> +    * - V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE
> +      - 0x00000001
> +      - The driver allows the application to try to change the default colorspace
> +	encoding. The application can ask to configure the colorspace of the
> +	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
> +	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
> +	See :ref:`v4l2-mbus-format` on how to do this.
> +    * - V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC
> +      - 0x00000002
> +      - The driver allows the application to try to change the default transform function.
> +	The application can ask to configure the transform function of
> +	the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
> +	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
> +	See :ref:`v4l2-mbus-format` on how to do this.
> +    * - V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
> +      - 0x00000004
> +      - The driver allows the application to try to change the default Y'CbCr
> +	encoding. The application can ask to configure the Y'CbCr encoding of the
> +	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
> +	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
> +	See :ref:`v4l2-mbus-format` on how to do this.
> +    * - V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC
> +      - 0x00000004
> +      - The driver allows the application to try to change the default HSV
> +	encoding. The application can ask to configure the HSV encoding of the
> +	subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
> +	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
> +	See :ref:`v4l2-mbus-format` on how to do this.
> +    * - V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION
> +      - 0x00000008
> +      - The driver allows the application to try to change the default
> +	quantization. The application can ask to configure the quantization of
> +	the subdevice when calling the :ref:`VIDIOC_SUBDEV_S_FMT <VIDIOC_SUBDEV_G_FMT>`
> +	ioctl with :ref:`V4L2_MBUS_FRAMEFMT_SET_CSC <mbus-framefmt-set-csc>` set.
> +	See :ref:`v4l2-mbus-format` on how to do this.
> +
>  Return Value
>  ============
>  
> diff --git a/include/uapi/linux/v4l2-mediabus.h b/include/uapi/linux/v4l2-mediabus.h
> index 123a231001a8..d0bc8df18ad5 100644
> --- a/include/uapi/linux/v4l2-mediabus.h
> +++ b/include/uapi/linux/v4l2-mediabus.h
> @@ -16,6 +16,8 @@
>  #include <linux/types.h>
>  #include <linux/videodev2.h>
>  
> +#define V4L2_MBUS_FRAMEFMT_SET_CSC	0x00000001
> +
>  /**
>   * struct v4l2_mbus_framefmt - frame format on the media bus
>   * @width:	image width
> @@ -24,8 +26,12 @@
>   * @field:	used interlacing type (from enum v4l2_field)
>   * @colorspace:	colorspace of the data (from enum v4l2_colorspace)
>   * @ycbcr_enc:	YCbCr encoding of the data (from enum v4l2_ycbcr_encoding)
> + * @hsv_enc:	HSV encoding of the data (from enum v4l2_hsv_encoding)
>   * @quantization: quantization of the data (from enum v4l2_quantization)
>   * @xfer_func:  transfer function of the data (from enum v4l2_xfer_func)
> + * @reserved2:  two reserved bytes that can be later used
> + * @flags:	flags (V4L2_MBUS_FRAMEFMT_*)
> + * @reserved:  reserved bytes that can be later used
>   */
>  struct v4l2_mbus_framefmt {
>  	__u32			width;
> @@ -33,10 +39,17 @@ struct v4l2_mbus_framefmt {
>  	__u32			code;
>  	__u32			field;
>  	__u32			colorspace;
> -	__u16			ycbcr_enc;
> +	union {
> +		/* enum v4l2_ycbcr_encoding */
> +		__u16			ycbcr_enc;
> +		/* enum v4l2_hsv_encoding */
> +		__u16			hsv_enc;
> +	};
>  	__u16			quantization;
>  	__u16			xfer_func;
> -	__u16			reserved[11];
> +	__u16			reserved2;
> +	__u32			flags;
> +	__u16			reserved[8];

Having to introduce a reserved2 field is pretty bad.

I would just make flags a __u16. If we ever need more than 16 bits, then it is easy
to add a flags2 field, but for now just stick to a __u16 flags field to avoid a
reserved2.

>  };
>  
>  #ifndef __KERNEL__
> diff --git a/include/uapi/linux/v4l2-subdev.h b/include/uapi/linux/v4l2-subdev.h
> index 5d2a1dab7911..e93970a2a38f 100644
> --- a/include/uapi/linux/v4l2-subdev.h
> +++ b/include/uapi/linux/v4l2-subdev.h
> @@ -65,19 +65,26 @@ struct v4l2_subdev_crop {
>  	__u32 reserved[8];
>  };
>  
> +#define V4L2_SUBDEV_MBUS_CODE_CSC_COLORSPACE	0x00000001
> +#define V4L2_SUBDEV_MBUS_CODE_CSC_XFER_FUNC	0x00000002
> +#define V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC	0x00000004
> +#define V4L2_SUBDEV_MBUS_CODE_CSC_HSV_ENC	V4L2_SUBDEV_MBUS_CODE_CSC_YCBCR_ENC
> +#define V4L2_SUBDEV_MBUS_CODE_CSC_QUANTIZATION	0x00000008
>  /**
>   * struct v4l2_subdev_mbus_code_enum - Media bus format enumeration
>   * @pad: pad number, as reported by the media API
>   * @index: format index during enumeration
>   * @code: format code (MEDIA_BUS_FMT_ definitions)
>   * @which: format type (from enum v4l2_subdev_format_whence)
> + * @flags: flags set by the driver, (V4L2_SUBDEV_MBUS_CODE_*)
>   */
>  struct v4l2_subdev_mbus_code_enum {
>  	__u32 pad;
>  	__u32 index;
>  	__u32 code;
>  	__u32 which;
> -	__u32 reserved[8];
> +	__u32 flags;
> +	__u32 reserved[7];
>  };
>  
>  /**
>