Table of Contents
The purpose of this page is to describe the Linux V4L2 driver for Xilinx VPSS Color Space Converter (CSC) soft IP. VPSS refers to the Video Processing Sub System.
This driver is for the CSC only mode of operation in the VPSS, please see the Product Guide for more details on its functionality and features.
The VPSS CSC driver supports only the following features are supported including:
|IP features||2018.1 to 2018.3||2019.1|
|One, two or four pixel-wide AXI4-Stream video interface||Yes|
|Video resolution support up to UHD at 60 fps||Yes|
|Run-time color space support for RGB, YUV 4:4:4, YUV 4:2:2, YUV 4:2:0||Yes|
|8, 10, 12, and 16 bits per component support|
Driver supports only 8 and 10 bpc formats
using only 8 bpc MEDIA BUS formats.
Yes* Driver supports only 8 and 10 bpc formats
using 8 and 10 bpc media bus formats
Missing Features / Known Issues / Limitations in Driver
- Works with fixed Vivado IP configuration as highlighted.
- Demo Window is not supported
- *Maximum color depth supported by the VPSS CSC soft IP driver is limited to 8 and 10 bpc.
- *12 and 16 bpc color depth width is not supported.
- Saturation Control is not supported
- Pre-computed color conversion coefficient matrix used.
- In future user supplied custom coefficients support may be added.
Video Processing Subsystem Release Notes and Known Issues
CONFIG_VIDEO_XILINX_VPSS_CSC and CONFIG_VIDEO_XILINX should be enabled.
Device tree binding
The dts node should be defined with correct hardware configuration. How to define the node is documented here:https://github.com/Xilinx/linux-xlnx/blob/master/Documentation/devicetree/bindings/media/xilinx/xlnx%2Cv-vpss-csc.txt
This driver is a V4L2 sub-device driver, which means it is designed to operate with a video device in it's graph. The driver has been tested with a Xilinx video device (a V4L2 capture device) that is backed by a DMA element (like Framebuffer Write IP). The V4L2 device driver for this IP cannot be tested in isolation by itself. The successful operation of the driver can be tested in two phases :
- Successful Creation of a Media Device
- Successful Frame Captures (or writing of buffers by the Frame-buffer Write IP)
media-ctl is a Linux user space utility that can control media entities, it is a part of a larger set of V4L2 tools called v4l-utils
media-ctl allows you to print the topology of your media pipeline and specify input and output pad properties.
Successful Frame Captures
Please see the Test Approach
section of the Frame Buffer Write Wiki for more details on how to capture frames.
The Red / Green / Blue gain values can be changed as shown in the Overview section and the captured images can be compared.
We need a ZCU102 Rev 1.0 board. Enable TPG, VPSS CSC and Framebuffer Write in kernel defconfig.
The color format set in the TPG is what will propagate to CSC sink pad.
The color format set in the CSC source pad and the one set on video node (Framebuffer Write) in yavta should match.
The device tree also needs to be update. If we are using a 8 bit design then TPG output video-width, VPSS CSC input and output ports video-width should all be 8.
For 10bpc design, the video-width is 10. The video-format for the TPG output port and VPSS CSC input port should match.
View the captured files in some viewer like yuvplayer.exe.
Driver has been tested on following boards:
- AR65449 - LogiCORE IP Video Processing Subsystem(VPSS) - Release Notes and Known Issues for the Vivado 2015.3 tool and later versions
- Add support for missing RGB 10bpc media bus format
- 2764687 v4l: xilinx: vpss-csc: Fix xcsc_set_format() for RBG 10 bpc
- Use 10 bit media codes
- Make max-width and max-height as mandatory dt properties
- Add check for max width and height from dt
- dddf225 v4l: xilinx-vpss-csc: Add check for max width and height
- Support for any to any color space conversion
- 3592a90 v4l: xilinx-vpss-csc: Support for any-to-any color space converison
- Initial driver version added
- 1437167 v4l: xilinx-vpss-csc: Any-to-any color space conversion
- 2c171c6 v4l: xilinx-vpss-csc: driver support for xilinx vpss csc