Re: [PATCH 13/14] docs: admin-guide: media: bcm2835-isp: Add documentation for bcm2835-isp
From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Date: 2022-11-21 23:43:43
Also in:
linux-media, linux-staging, lkml
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 <redacted> Document device nodes, frame buffer formats and initial set of configuraiton that can be set from userspace to configure the pipeline.
s/configuraiton/configuration/
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Signed-off-by: Naushir Patuck <redacted> Signed-off-by: Umang Jain <redacted> --- .../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.rstdiff --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 ?
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+ - 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_dpcdiff --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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel