LVGL on Linux

Raspberry Pi : Model 3B running Rasberry PI OS (64)
Display : Waveshare 2.8" 480x640 with Capacitive Touch

DISPLAY SETUP

• Comment out dtoverlay=vc4-fkms-V3D in /boot/config.txt
• Add the following TFT/Touch configuration at the end of /boot/config.txt

gpio=0-9=a2
gpio=12-17=a2
gpio=20-25=a2
dtoverlay=dpi24
enable_dpi_lcd=1
display_default_lcd=1
extra_transpose_buffer=2
dpi_group=2
dpi_mode=87
dpi_output_format=0x7F216
hdmi_timings=480 0 26 16 10 640 0 25 10 15 0 0 0 60 0 32000000 1
dtoverlay=waveshare-28dpi-3b-4b
dtoverlay=waveshare-28dpi-3b
dtoverlay=waveshare-28dpi-4b

• Add the following for Display rotation in /boot/config.txt
display_rotate=1 #1：90；2: 180； 3: 270
• Follow these steps to align touch panel to the display rotation

sudo apt-get install xserver-xorg-input-libinput
sudo mkdir /etc/X11/xorg.conf.d
sudo cp /usr/share/X11/xorg.conf.d/40-libinput.conf /etc/X11/xorg.conf.d/
sudo nano /etc/X11/xorg.conf.d/40-libinput.conf

// Add the following line where Identifier has 'touchscreen'
Option "CalibrationMatrix" "0 1 0 -1 0 1 0 0 1"

// 90 degree: Option "CalibrationMatrix" "0 1 0 -1 0 1 0 0 1"
// 180 degree: Option "CalibrationMatrix" "-1 0 1 0 -1 1 0 0 1"
// 270 degree: Option "CalibrationMatrix" "0 -1 1 1 0 0 0 0 1"

• Download and Copy 3 overlay files inside /boot/overlays folder https://www.waveshare.com/wiki/File:28DPIB_DTBO.zip

USING SDL

This works if you have Raspberry PI OS with desktop running

• Install SDL
  sudo apt-get update && sudo apt-get install -y build-essential libsdl2-dev
• Clone LVGL Simulator repo
  git clone --recursive https://github.com/littlevgl/pc_simulator.git
• Install cmake
  sudo apt install cmake
• Compile and build
  cd pc_simulator/ && mkdir build && cd build && cmake .. && make -j4
• Run the Application built using
  DISPLAY=:0 ./../bin/main
• To make your app FULL SCREEN, add below line inside lv_drv_conf.h
#define SDL_FULLSCREEN 1

USING LINUX FRAME BUFFER /dev/fb0

(WORK IN PROGRESS)

TASKS

• LVGL 8.x display
• Touch,Mouse and Keyboard input
• Document the sample including base setup and display setup

NOTE

When cloning this repository, make sure to download submodules otherwise you will be missing required components.
git submodule update --init --recursive

References

Display setup instructions here
Frame Buffer method based on this blog post.