GamePi20 Drivers for Linux Kernel 5.4 and Above

Note: Tested For RetroPie 4.7 and Raspbian Buster and above, may not work with old distro

First, enable the SPI interface by using sudo raspi-config and go to Interface Options > SPI

or by editing /boot/config.txt and add the following line dtparam=spi=on

To verify spi is enabled, lsmod | grep spi_ will show something, otherwise it won't show up anything

TFT Drivers / Device Tree Overlay Source (DTS) for GamePi20

NOTE:The old modules method doesnt work on linux kernel 5.4. So device tree overlay is required to enable gamepi20 tft The device tree overlay for gamepi20 tft is updated for linux kernel 5.4,

Compile ST7789V GamePi TFT device tree overlay source with this command:

 sudo dtc -@ -I dts -O dtb -o /boot/overlays/gamepi20.dtbo gamepi20.dts

After compiling, add the gamepi20 dtoverlay to /boot/config.txt

First sudo nano /boot/config.txt to open text editor in superuser, then add the following code end of the line

dtoverlay=gamepi20

Lastly reboot to take effect by typing sudo reboot

How to check Drivers is successsfully loaded

The command ls /dev/ should show /dev/fb1

The command lsmod | grep st7789 should showup

The command dmesg | grep st7789 should show no errors

Framebuffer Copy |fbcp

You need to install fbcp to allow /dev/fb0 to copy the framebuffer to /dev/fb1 which is the ST7789V TFT LCD Panel

First make sure you have cmake and git install

sudo apt-get install cmake git

Then cd to home-directory for cloning the fbcp, compiling the source code and also to install the fbcp to /usr/local/bin/

cd ~
git clone https://github.com/tasanakorn/rpi-fbcp
cd rpi-fbcp/
mkdir build
cd build/
cmake ..
make
sudo install fbcp /usr/local/bin/fbcp

How to check fbcp is working

run fbcp in command and it should show up the same image as the HDMI output

if not, go back and check whether device tree overlay is successfully installed.

CTRL+C to exit fbcp after verifying is working

Install fbcp as services

First we will save fbcp& to /etc/rc.local

sudo nano /etc/rc.local

Edit the file so that fbcp& is before exit 0.

REMEMBER IT SHOULD BE fbcp& , THE & IS VERY IMPORTANT. THIS WILL MAKE SURE OTHER SYSTEM PROCESSES CAN CONTINUE LOADING WITHOUT WAITING FBCP TO CLOSE

Edit /boot/config.txt so that the words would not be too small, and will fit into the TFT Panel

Copy and paste this into /boot/config.txt

hdmi_force_hotplug=1
hdmi_cvt=640 480 60 1 0 0 0
hdmi_group=2
hdmi_mode=1
hdmi_mode=87
audio_pwm_mode=2
dtoverlay=audremap,pins_18_19

• dtoverlay=audremap,pins_18_19 sets the Audio output via the PWM GPIO pin 12 GPIO=18 (PWM CLK)
• audio_pwm_mode=2 enable better PWM output

Then sudo reboot and the TFT should show up the same image as HDMI output

Setup the GPIO pins for GAMEPI20 Joystick/Controller

run this command in subsequent to setup the kernel joystick driver

git clone https://github.com/waveshare/mk_arcade_joystick_rpi.git
cd mk_arcade_joystick_rpi
sudo ./install.sh 3
sudo reboot

Finally after the reboot setup the controller via the initial input configuration.

Short press the button to save input, Long press a button to skip

Troubleshoot if there is no sound

Be sure to change the audio device to PCM in Main Menu > Sound Settings in RetroPie as alsamixer is slowly depreciated