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    SubjectRe: [PATCH 13/14] docs: admin-guide: media: bcm2835-isp: Add documentation for bcm2835-isp
    Hi Umang and Naush,

    Thank you for the patch.

    On Tue, Nov 22, 2022 at 03:17:21AM +0530, Umang Jain wrote:
    > From: Naushir Patuck <naush@raspberrypi.com>
    >
    > Document device nodes, frame buffer formats and initial set of
    > configuraiton that can be set from userspace to configure the pipeline.

    s/configuraiton/configuration/

    > Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
    > Signed-off-by: Umang Jain <umang.jain@ideasonboard.com>
    > ---
    > .../admin-guide/media/bcm2835-isp.rst | 127 ++++++++++++++++++
    > .../userspace-api/media/drivers/index.rst | 1 +
    > 2 files changed, 128 insertions(+)
    > create mode 100644 Documentation/admin-guide/media/bcm2835-isp.rst
    >
    > diff --git a/Documentation/admin-guide/media/bcm2835-isp.rst b/Documentation/admin-guide/media/bcm2835-isp.rst
    > new file mode 100644
    > index 000000000000..e1c19f78435e
    > --- /dev/null
    > +++ b/Documentation/admin-guide/media/bcm2835-isp.rst
    > @@ -0,0 +1,127 @@
    > +.. SPDX-License-Identifier: GPL-2.0
    > +
    > +BCM2835 ISP Driver
    > +==================
    > +
    > +Introduction
    > +------------
    > +
    > +The BCM2835 Image Sensor Pipeline (ISP) is a fixed function hardware pipeline
    > +for performing image processing operations. Images are fed to the input
    > +of the ISP through memory frame buffers. These images may be in various YUV,
    > +RGB, or Bayer formats.

    Does the ISP really support RGB or YUV input images ? Is this supported
    by the driver ?

    > A typical use case would have Bayer images obtained from
    > +an image sensor by the BCM2835 Unicam peripheral, written to a memory
    > +frame buffer, and finally fed into the input of the ISP. Two concurrent output
    > +images may be generated in YUV or RGB format at different resolutions.
    > +Statistics output is also generated for Bayer input images.
    > +
    > +The bcm2835-isp driver exposes the following media pads as V4L2 device nodes:

    This sounds weird. Pads are not video nodes, are they ? Or are those
    MMAL pads ?

    > +
    > +.. tabularcolumns:: |l|l|l|l|
    > +
    > +.. cssclass: longtable
    > +
    > +.. flat-table::
    > +
    > + * - *Pad*
    > + - *Direction*
    > + - *Purpose*
    > + - *Formats*
    > +
    > + * - "bcm2835-isp0-output0"
    > + - sink
    > + - Accepts Bayer, RGB or YUV format frame buffers as input to the ISP HW
    > + pipeline.
    > + - :ref:`RAW8 <V4L2-PIX-FMT-SRGGB8>`,
    > + :ref:`RAW10P <V4L2-PIX-FMT-SRGGB10P>`,
    > + :ref:`RAW12P <V4L2-PIX-FMT-SRGGB12P>`,
    > + :ref:`RAW14P <V4L2-PIX-FMT-SRGGB14P>`,
    > + :ref:`RAW16 <V4L2-PIX-FMT-SRGGB16>`,
    > + :ref:`RGB24/BGR24 <V4L2-PIX-FMT-RGB24>`,
    > + :ref:`YUYV <V4L2-PIX-FMT-YUYV>`,
    > + :ref:`YVYU <V4L2-PIX-FMT-YVYU>`,
    > + :ref:`UYVY <V4L2-PIX-FMT-UYVY>`,
    > + :ref:`VYUY <V4L2-PIX-FMT-VYUY>`,
    > + :ref:`YUV420/YVU420 <V4L2-PIX-FMT-YUV420>`
    > +
    > + * - "bcm2835-isp0-capture1"
    > + - source
    > + - High resolution YUV or RGB processed output from the ISP.
    > + - :ref:`RGB565 <V4L2-PIX-FMT-RGB565>`,
    > + :ref:`RGB24/BGR24 <V4L2-PIX-FMT-RGB24>`,
    > + :ref:`ABGR32 <V4L2-PIX-FMT-ABGR32>`,
    > + :ref:`YUYV <V4L2-PIX-FMT-YUYV>`,
    > + :ref:`YVYU <V4L2-PIX-FMT-YVYU>`,
    > + :ref:`UYVY <V4L2-PIX-FMT-UYVY>`,
    > + :ref:`VYUY <V4L2-PIX-FMT-VYUY>`.
    > + :ref:`YUV420/YVU420 <V4L2-PIX-FMT-YUV420>`,
    > + :ref:`NV12/NV21 <V4L2-PIX-FMT-NV12>`,
    > +
    > + * - "bcm2835-isp0-capture2"
    > + - source
    > + - Low resolution YUV processed output from the ISP. The output of
    > + this pad cannot have a resolution larger than the "bcm2835-isp0-capture1" pad in any dimension.
    > + - :ref:`YUYV <V4L2-PIX-FMT-YUYV>`,
    > + :ref:`YVYU <V4L2-PIX-FMT-YVYU>`,
    > + :ref:`UYVY <V4L2-PIX-FMT-UYVY>`,
    > + :ref:`VYUY <V4L2-PIX-FMT-VYUY>`.
    > + :ref:`YUV420/YVU420 <V4L2-PIX-FMT-YUV420>`,
    > + :ref:`NV12/NV21 <V4L2-PIX-FMT-NV12>`,
    > +
    > + * - "bcm2835-isp0-capture1"

    Is that capture3 ?

    Maybe the video nodes should be renamed to make their purpose clearer ?

    > + - source
    > + - Image statistics calculated from the input image provided on the
    > + "bcm2835-isp0-output0" pad. Statistics are only available for Bayer
    > + format input images.
    > + - :ref:`v4l2-meta-fmt-bcm2835-isp-stats`.
    > +
    > +Pipeline Configuration
    > +----------------------
    > +
    > +The ISP pipeline can be configure through user-space by calling
    > +:ref:`VIDIOC_S_EXT_CTRLS <VIDIOC_G_EXT_CTRLS>` on the “bcm2835-isp0-output0”
    > +node with the appropriate parameters as shown in the table below.
    > +
    > +.. tabularcolumns:: |p{2cm}|p{5.0cm}|
    > +
    > +.. cssclass: longtable
    > +
    > +.. flat-table::
    > +
    > + * - *id*
    > + - *Parameter*
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_CC_MATRIX``
    > + - struct :c:type:`bcm2835_isp_custom_ccm`
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_LENS_SHADING``
    > + - struct :c:type:`bcm2835_isp_lens_shading`
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_BLACK_LEVEL``
    > + - struct :c:type:`bcm2835_isp_black_level`
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_GEQ``
    > + - struct :c:type:`bcm2835_isp_geq`
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_GAMMA``
    > + - struct :c:type:`bcm2835_isp_gamma`
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_DENOISE``
    > + - struct :c:type:`bcm2835_isp_denoise`
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_SHARPEN``
    > + - struct :c:type:`bcm2835_isp_sharpen`
    > +
    > + * - ``V4L2_CID_USER_BCM2835_ISP_DPC``
    > + - struct :c:type:`bcm2835_isp_dpc`
    > +
    > +++++++++++++++++++++++++
    > +Configuration Parameters
    > +++++++++++++++++++++++++
    > +
    > +.. kernel-doc:: include/uapi/linux/bcm2835-isp.h
    > + :functions: bcm2835_isp_rational bcm2835_isp_ccm bcm2835_isp_custom_ccm
    > + bcm2835_isp_gain_format bcm2835_isp_lens_shading
    > + bcm2835_isp_black_level bcm2835_isp_geq bcm2835_isp_gamma
    > + bcm2835_isp_denoise bcm2835_isp_sharpen
    > + bcm2835_isp_dpc_mode bcm2835_isp_dpc
    > diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst
    > index 32f82aed47d9..34e0d7102ef0 100644
    > --- a/Documentation/userspace-api/media/drivers/index.rst
    > +++ b/Documentation/userspace-api/media/drivers/index.rst
    > @@ -31,6 +31,7 @@ For more details see the file COPYING in the source distribution of Linux.
    > :maxdepth: 5
    > :numbered:
    >
    > + bcm2835-isp
    > ccs
    > cx2341x-uapi
    > dw100

    --
    Regards,

    Laurent Pinchart

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