pwmCtrl/pwm.go

package main

import (
	"log"
	"os"
	"strconv"

	"github.com/stianeikeland/go-rpio/v4"
)

type pwmControl struct {
	freq        int
	cycleLength uint32
	pin         rpio.Pin
}

func NewPwmControl(pin rpio.Pin) *pwmControl {
	pwm := pwmControl{pin: pin, freq: 64000, cycleLength: 32}
	pwm.Init()
	return &pwm
}

func (pwm *pwmControl) Init() {
	pwm.pin.Mode(rpio.Pwm)
	pwm.pin.Freq(pwm.freq)
	pwm.pin.DutyCycle(0, pwm.cycleLength)
}

//SetPerc sets the dutylength proportional to cycleLength in percent
func (pwm *pwmControl) SetPerc(perc uint32) {
	dutylen := (perc * pwm.cycleLength) / 100
	pwm.pin.DutyCycle(uint32(dutylen), pwm.cycleLength)
}

func StartPwm(changechan chan change) {
	err := rpio.Open()
	if err != nil {
		os.Exit(1)
	}
	defer rpio.Close()

	pwmMonitorBrightness := NewPwmControl(rpio.Pin(19))
	pwmFanSpeed := NewPwmControl(rpio.Pin(20))

	for {
		change := <-changechan
		value, err := strconv.Atoi(change.value)
		if err != nil {
			log.Printf("error updating %s: %s\n", "monitorBrightness", err)
			continue
		}
		if value < 0 || value > 100 {
			log.Printf("error updating %s: value out of range %v\n", "monitorBrightness", value)
			continue
		}

		switch change.kind {
		case "monitorBrightness":
			pwmMonitorBrightness.SetPerc(uint32(value))
		case "fanSpeed":
			pwmFanSpeed.SetPerc(uint32(value))
		}
	}
}