Introduction

This is BPS layer for LicheePi Zero Dock which enables most of it's media capabilities. Including:

1. video engine (h.264 decoder)
2. display engine (with 800x480p LCD)
3. mipi-csi2 (with ov5640 camera)
4. audio codec

Also following items are active too

1. Ethernet (onboard 10/100Mbps LAN) with dhcp
2. WiFi (rtl8723bs SDIO module). Check /etc/wap_supplicant/wpa_supplicant-nl80211-wlan0.conf
3. USB otg (host mode)

Before using LicheePi-Zero-Dock mipi-csi2 interface, please check v3s-mipi-csi2 repository. You need to do some hardware things!

Getting started

1. Clone required layers:

git clone git://git.yoctoproject.org/poky -b kirkstone
cd poky/
git clone https://github.com/linux-sunxi/meta-sunxi.git -b kirkstone
git clone https://github.com/openembedded/meta-openembedded.git -b kirkstone
git clone git@github.com:ArashEM/meta-licheepi-media.git -b kirkstone
cd ../

2. Export template configuration path and initialize build environment

export TEMPLATECONF=${TEMPLATECONF:-meta-licheepi-media/conf}
source poky/oe-init-build-env licheepi-zero-dock

3. Start build process

bitbake media-image

4. Flash wic image into your SD card (it must be gunziped first)

sudo dd if=tmp/deploy/images/licheepi-zero-dock/media-image-licheepi-zero-dock.wic of=/dev/sdX

5. Enjoy :-)

GStreamer example

1. Turn backlight on

echo 36 > /sys/class/gpio/export 
echo out > /sys/class/gpio/gpio36/direction 
echo 1 > /sys/class/gpio/gpio36/value

2. Configure media pipeline

media-ctl -d /dev/sun6i-isp-media --set-v4l2 "'ov5647 0-0036':0[fmt:SBGGR10_1X10/1296x972 field:none]"
media-ctl -d /dev/sun6i-isp-media --set-v4l2 "'sun6i-mipi-csi2':1[fmt:SBGGR10_1X10/1296x972]"
media-ctl -d /dev/sun6i-isp-media --set-v4l2 "'sun6i-csi-bridge':1[fmt:SBGGR10_1X10/1296x972]"
media-ctl -d /dev/sun6i-isp-media --set-v4l2 "'sun6i-isp-proc':1[fmt:SBGGR10_1X10/1296x972]"

3. Configure camera for automatic gain, exposure and white balancing

v4l2-ctl -d /dev/v4l-subdev3 --set-ctrl gain_automatic=1
v4l2-ctl -d /dev/v4l-subdev3 --set-ctrl auto_exposure=0
v4l2-ctl -d /dev/v4l-subdev3 --set-ctrl white_balance_automatic=1

4. Start a pipeline from camera to LCD (gray scale mode)

gst-launch-1.0  v4l2src device=/dev/sun6i-isp-capture num-buffers=150 \
! video/x-raw,format=NV12,width=1296,height=972,framerate=30/1 \
! videoscale \
! video/x-raw,width=648,height=486 \
! videoconvert  \
! fpsdisplaysink video-sink=fbdevsink sync=false

Note: I'm using 648x486 for scaling because it's easier for videoscale to 1/4 image rather than 800x480 which is actual LCD size.

Notes

1. You can configure your image before burning into SD card. for example setting wpa-psk.
   first check start sector of interested partition

file media-image-licheepi-zero-dock.wic
media-image-licheepi-zero-dock.wic: DOS/MBR boot sector; partition 1 : ID=0xc, active, start-CHS (0x20,0,1), end-CHS (0x29f,3,32), startsector 4096, 81920 sectors; partition 2 : ID=0x83, start-CHS (0x2a0,0,1), end-CHS (0x3ff,3,32), startsector 86016, 1783808 sectors; partition 3 : ID=0x82, start-CHS (0x3ff,3,32), end-CHS (0x3ff,3,32), startsector 1871872, 204800 sectors

Then mount it via offset argument:

sudo mount -o rw,offset=$((512*86016)) file media-image-licheepi-zero-dock.wic /mnt/

2. swap partition is necessary! So consider using high speed SD card. Otherwise you may encounter issue using GStreamer.

3. In order to compile libcamera with poky sdk you need jinja2, ply and pyyaml. Which are not shipped with sdk. Easy way to install them is using pip. This way packages are install into /opt/sdk/sysroots/x86_64-pokysdk-linux/usr/lib/python3.10/site-packages. It's local repository of packages inside sdk sysroot.

source /opt/sdk/environment-setup-cortexa7t2hf-neon-poky-linux-gnueabi
python3.10 -m ensurepip --upgrade
python3.10 -m pip install ply jinja2 pyyaml