OrangePi5 PWM Fan Control

fan.c

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>

#include <wiringPi.h>
#include <softPwm.h>

#define PIN 10	
#define	RANGE 100

int getVal (char *file) {
  long int l;
  FILE *ptr;
  ptr = fopen(file, "r");
  if (ptr == NULL) {
    return 0;
  }
  fscanf(ptr, "%ld", &l);
  fclose(ptr);
  return l / 1000;
}

int main (int argc, char *argv[])
{
  if (argc < 2) {
    printf("Your files containing thermals eg: /sys/class/thermal/*/temp");
    return -1;
  }

  wiringPiSetup ();
  softPwmCreate (PIN, 0, RANGE);

  int max = 0;
  int pmax = 60;
  int val = 0;
  int i;

  while (1==1) {
    // Get Max thermal
    max = 0;
    for (i = 1; i < argc; i++) {
      val = getVal(argv[i]);
      max = max > val ? max : val;
    }

    // Adjust current thermal (slow backoff)
    pmax = max >= pmax ? max : pmax - 1;

    // Calc Fan speed
    val = (pmax - 40) * 4; // 40-65
    val = val > 100 ? 100 : val;
    val = val < 0 ? 0 : val;

    // Set Fan
    printf("%3dC - %3dC - %3d%%\n", max, pmax, val);
    softPwmWrite (PIN, val);
    delay(1000);
  }
}