NXP IMX95LPD5EVK-19CM board TEVS Camera Usage Guide

Introduction

This article guides you how to get started using TEVS Series camera on NXP IMX95LPD5EVK-19CM board.

Supported Camera Modules

Overview

• Prepare adapter board and cable for TechNexion camera

• Prepare Yocto demo image for testing TechNexion camera

• Build Yocto

• Develop Linux kernel

• Instructions for testing camera

• Trouble shooting

Prepare adapter board and cable for TechNexion camera

Prepare adapter board and cable connect to EVK board:

Prepare Yocto demo image for testing TechNexion camera

The demo image contains the required device tree blobs and camera drivers to enable TechNexion TEVS Series cameras.
Choose the correct demo image that is compatible with the EVK board you have.

Prebuilt demo images can be available for download via TechNexion's server.
Image Download Link

Flash image to SD card

Under Windows:
balena etcher

Under Linux:
bmap-tools

$ sudo apt-get update
$ sudo apt-get install bmap-tools

Ensure the boot mode is configured as boot from SD card.
i.MX 95 LPD5 EVK Quick Start Guide

Please refer to Instructions for testing camera section for camera testing steps.

Build Yocto

Fetch Yocto source
Build Yocto

Develop Linux kernel

Fetch and compile Linux kernel

The Build Environment

Tested under ubuntu 20.04.
Using aarch64-linux-gnu-gcc 9.4.0 cross compiler.

Supported TechNexion Linux kernel branch for TEVS Series cameras

Install cross-compile & dependency tools.

$ sudo apt update
$ sudo apt install -y gcc-aarch64-linux-gnu libncurses-dev libssl-dev bison flex git make

Download the source code.

$ git clone https://github.com/TechNexion/linux-tn-imx.git -b tn-imx_6.6.52_2.2.0-next

Set cross-compile environment & the kernel config.

$ export ARCH=arm64
$ export CROSS_COMPILE=/usr/bin/aarch64-linux-gnu-
$ cd linux-tn-imx
~/linux-tn-imx$ make imx_v8_defconfig

Compile the kernel & module driver.

# compile kernel
~/linux-tn-imx$ make -j$(nproc)
# create kernel module folder
~/linux-tn-imx$ mkdir -p ./modules
# compile module driver
~/linux-tn-imx$ rm -rf ./modules/*
~/linux-tn-imx$ make INSTALL_MOD_PATH=./modules modules_install

Change kernel Image, DTB & modules.

~/linux-tn-imx/$ cp arch/arm64/boot/Image  <mount_folder>/boot/Image
~/linux-tn-imx/$ cp arch/arm64/boot/dts/freescale/imx95-19x19-evk-tevs-tev-nxp.dts  <mount_folder>/boot/
~/linux-tn-imx/$ sudo cp -r ./modules/lib/modules/*  <mount_folder>/root/lib/modules/

Instructions for testing camera

Specify camera DTB in u-boot

1. Connect debug console cable to NXP IMX95LPD5EVK-19CM.

2. Power on board, and enter u-boot prompt.

3. Specify camera dtb via fdtfile u-boot environment variable.

u-boot=> setenv fdtfile imx95-19x19-evk-tevs-tev-nxp.dtb

4. Continue boot process.

u-boot=> saveenv
u-boot=> boot

Setup the media controller before camera streaming

We can check whether camera have been link via media control command.

$ media-ctl -p

Get the media controller information as follows.

Media controller API version 6.6.23

Media device information

------------------------

driver mxc-isi

model FSL Capture Media Device

serial

bus info platform:4ad50000.isi

hw revision 0x0

driver version 6.6.23

Device topology

- entity 1: crossbar (13 pads, 9 links, 8 routes)

type V4L2 subdev subtype Unknown flags 0

device node name /dev/v4l-subdev0

routes:

2/0 -> 5/0 [ACTIVE]

2/0 -> 6/0 [ACTIVE]

2/0 -> 7/0 [ACTIVE]

2/0 -> 8/0 [ACTIVE]

2/0 -> 9/0 [ACTIVE]

2/0 -> 10/0 [ACTIVE]

2/0 -> 11/0 [ACTIVE]

2/0 -> 12/0 [ACTIVE]

pad0: Sink

pad1: Sink

pad2: Sink

[stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]

<- "4ac10000.syscon:formatter@20":1 [ENABLED,IMMUTABLE]

pad3: Sink

pad4: Sink

pad5: Source

[stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:srgb xfer:srgb ycbcr:601 quantization:lim-range]

-> "mxc_isi.0":0 [ENABLED,IMMUTABLE]

…

- entity 15: mxc_isi.0 (2 pads, 2 links, 0 routes)

type V4L2 subdev subtype Unknown flags 0

device node name /dev/v4l-subdev1

pad0: Sink

[stream:0 fmt:UYVY8_1X16/1920x1080 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range

compose.bounds:(0,0)/1920x1080

compose:(0,0)/1920x1080]

<- "crossbar":5 [ENABLED,IMMUTABLE]

pad1: Source

[stream:0 fmt:YUV8_1X24/1920x1080 field:none colorspace:jpeg xfer:srgb ycbcr:601 quantization:full-range

crop.bounds:(0,0)/1920x1080

crop:(0,0)/1920x1080]

-> "mxc_isi.0.capture":0 [ENABLED,IMMUTABLE]

- entity 18: mxc_isi.0.capture (1 pad, 1 link)

type Node subtype V4L flags 0

device node name /dev/video0

pad0: Sink

<- "mxc_isi.0":1 [ENABLED,IMMUTABLE]

…

Or it will be easier to understand if you output it as an image.

$ media-ctl --print-dot > graph.dot
$ dot -Tpng graph.dot > graph.png
# if you don't have tool, you need to install it as follows.
# sudo apt-get install -y graphviz

Modify the route through the “crossbar” and only keep the channel of video0.

$ media-ctl -R "'crossbar' [2/0 -> 5/0 [1], 2/0 -> 6/0 [0], 2/0 -> 7/0 [0], 2/0 -> 8/0 [0], 2/0 -> 9/0 [0], 2/0 -> 10/0 [0], 2/0 -> 11/0 [0], 2/0 -> 12/0 [0]]"

Enable the link between TEVS and CSI device.

$ media-ctl -l "'tevs 2-0048':0 -> 'csidev-4ad30000.csi':0 [1]"

You can list camera formats, resolutions and frame interval via v4l2 control command.

# formats
$ v4l2-ctl -d /dev/v4l-subdev11 --list-subdev-mbus-codes
ioctl: VIDIOC_SUBDEV_ENUM_MBUS_CODE (pad=0)
        0x200f: MEDIA_BUS_FMT_UYVY8_1X16

# resolutions
$ v4l2-ctl -d /dev/v4l-subdev11 --list-subdev-framesize code=0x200f
ioctl: VIDIOC_SUBDEV_ENUM_FRAME_SIZE (pad=0)
        Size Range: 640x480 - 640x480
        Size Range: 1280x720 - 1280x720
        Size Range: 1280x800 - 1280x800

# frame interval of resolution
$ v4l2-ctl -d /dev/v4l-subdev11 --list-subdev-frameintervals width=640,height=480,code=0x200f
ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0)
        Interval: 0.017s (60.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev11 --list-subdev-frameintervals width=1280,height=720,code=0x200f
ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0)
        Interval: 0.017s (60.000 fps)

$ v4l2-ctl -d /dev/v4l-subdev11 --list-subdev-frameintervals width=1280,height=800,code=0x200f
ioctl: VIDIOC_SUBDEV_ENUM_FRAME_INTERVAL (pad=0)
        Interval: 0.017s (60.000 fps)

Set the media controller resolution to 1280×720.

$ media-ctl -V "'crossbar':2 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'mxc_isi.0':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'4ac10000.syscon:formatter@20':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'csidev-4ad30000.csi':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"
$ media-ctl -V "'tevs 2-0048':0 [fmt:UYVY8_1X16/1280x720 field:none colorspace:srgb xfer:srgb ycbcr:601]"

Start camera video stream via gstreamer

Specify the capture device you just get and start gstreamer to get video stream on screen.

$ gst-launch-1.0 v4l2src device=/dev/video0 ! "video/x-raw, format=YUY2, width=1280, height=720" ! waylandsink sync=false

Trouble shooting

Boot up NXP IMX95LPD5EVK-19CM and check initialization of TEVS driver.
If it shows below messages, the driver is initialized correctly.

$ dmesg -t | grep tevs

tevs 1-0048: tevs_probe() device node: tevs@48
tevs 1-0048: Version:24.9.0.1
tevs 1-0048: Product:TEVS-AR0234, HeaderVer:3, MIPI_Rate:800
tevs 1-0048: probe success