Belabox install script to add service for setting physical GPIO pins 15 and 40 to OUT and LOW for specific 4G/5G hats

gpio_installer.sh

#!/bin/bash

####################################
#
# This script is designed for use with the official Belabox images on the supported Rockchip RK3588 boards
# in combination with the SpotPear 4G/5G M.2 modem hats:
# https://spotpear.com/index.php/shop/Raspberry-Pi-M.2-4G-5G-GSM-GPRS-EDGE.html
#
# The Belabox image, at least on the Orange Pi 5 Plus, defaults available GPIO pins to IN with a pullup.
# Physical pins 15 and 40 tie to modem POWER and RESET pins with these hats and the defaults will keep
# the modems in a reset state.
#
# This installer provides a script configured as a system service to set these pins to OUT and LOW, ensuring
# the modems are in a running state on boot.
#
# Please reach out to Vchat20 on the Belabox Discord server for any questions.
#
####################################

# Check if the script is run as root
if [[ $EUID -ne 0 ]]; then
    echo "This script must be run as root. Attempting to elevate privileges..."
    exec sudo "$0" "$@"
fi

# Path for the GPIO script
GPIO_SCRIPT_PATH="/usr/local/bin/gpio-script.sh"

# Create the GPIO script
cat << 'EOF' > $GPIO_SCRIPT_PATH
#!/bin/bash

# Determine the board model
MODEL=$(cat /sys/firmware/devicetree/base/model)

# Initialize GPIO pins based on board model
if [[ "$MODEL" == *"Orange Pi 5 Plus"* ]]; then
    GPIO_PIN1=99
    GPIO_PIN2=40
elif [[ "$MODEL" == *"Radxa ROCK 5B"* || "$MODEL" == *"Banana Pi BPI-W3"* ]]; then # Matches Rock 5B/5B+ amd BPI-W3. All share same GPIO pin numbers
    GPIO_PIN1=107
    GPIO_PIN2=112
elif [[ "$MODEL" == *"Radxa ROCK 5A"* ]]; then
    GPIO_PIN1=137
    GPIO_PIN2=140
else
    echo "Unknown board model: $MODEL"
    exit 1
fi

echo "Running on board: $MODEL"
echo "Using GPIO pins $GPIO_PIN1 and $GPIO_PIN2"

# Export the GPIO pins
echo "$GPIO_PIN1" > /sys/class/gpio/export
echo "$GPIO_PIN2" > /sys/class/gpio/export

# Set the GPIO pins to "out" direction
echo "out" > /sys/class/gpio/gpio"$GPIO_PIN1"/direction
echo "out" > /sys/class/gpio/gpio"$GPIO_PIN2"/direction

# Set the GPIO pins to "low"
echo "0" > /sys/class/gpio/gpio"$GPIO_PIN1"/value
echo "0" > /sys/class/gpio/gpio"$GPIO_PIN2"/value

echo "GPIO pins $GPIO_PIN1 and $GPIO_PIN2 set to out and low."
exit 0
EOF

# Make the GPIO script executable
chmod +x $GPIO_SCRIPT_PATH

# Path for the service file
SERVICE_FILE_PATH="/etc/systemd/system/gpio-service.service"

# Create the service file
cat << EOF > $SERVICE_FILE_PATH
[Unit]
Description=GPIO Control Service        
After=multi-user.target

[Service]
ExecStart=$GPIO_SCRIPT_PATH
Restart=no

[Install]
WantedBy=multi-user.target
EOF

# Reload systemd manager configuration
systemctl daemon-reload

# Enable the service to start at boot
systemctl enable gpio-service.service

# Start the service immediately
systemctl start gpio-service.service

echo "Installation complete. The GPIO service is now running and will start at boot."