CPU fan control script for banana-pi-BPI-R4 under immortalwrt firmware

banana-pi-BPI-R4 CPU fan control script under the immortalwrt firmware

The firmware for banana-pi-BPI-R4 provided officially can really be said to be very bad.

Even the basic wget-ssl is not provided. Flash the official openwrt system of banana-pi-BPI-R4.

Even the most basic opkg update cannot be executed.

The reason is that wget-ssl is not installed. The source address needs to be changed to http, and then install wget-ssl.

The official openwrt firmware of banana-pi-BPI-R4 is based on kernel 5.1, and the wifi driver is also closed source.

In addition to a very strong WiFi signal and support for MLO, the official firmware doesn’t have much appeal.

The following is a CPU fan control script for banana-pi-BPI-R4 based on immortalwrt24.10.0.

vi /sbin/fan-speed

#!/bin/sh /etc/rc.common

if [ ! -f /sys/class/pwm/pwmchip0/export ]; then
    exit 0
fi

### 导出 PWM 通道 ###
echo 1 > /sys/class/pwm/pwmchip0/export 2>/dev/null

### 检查 PWM 通道是否已导出 ###
if [ -d /sys/class/pwm/pwmchip0/pwm1 ]; then
    echo 10000 > /sys/class/pwm/pwmchip0/pwm1/period
    echo 7000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
    echo normal > /sys/class/pwm/pwmchip0/pwm1/polarity
    echo 1 > /sys/class/pwm/pwmchip0/pwm1/enable
else
    echo "Failed to export PWM channel 1!"
    exit 1
fi

### 温度控制循环 ###
while :
do
    sleep 20
    result=$(cat /sys/class/thermal/thermal_zone0/temp)
    temperature=$((result))

    if [ ${temperature} -ge 50000 ]; then
        echo 5000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
    fi

    if [ ${temperature} -ge 60000 ]; then
        echo 1000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
    fi

    if [ ${temperature} -le 48000 ]; then
        echo 7000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
    fi

    if [ ${temperature} -le 40000 ]; then
        echo 10000 > /sys/class/pwm/pwmchip0/pwm1/duty_cycle
    fi
done
startup on boot

vi /etc/rc.local
# Put your custom commands here that should be executed once
# the system init finished. By default this file does nothing.
fan-speed
exit 0