Examples of setting the drive strength of a Raspberry Pi GPIO PAD using either pigpio or WiringPi

pigpio.c

// gcc -Wall -O3 -pthread -o set_drive_strength pigpio.c -lpigpio

#include <stdlib.h>
#include <pigpio.h>

int main(int argc, char *argv[]) {
   if (gpioInitialise() < 0) return 1;

   int strength_ma = argc > 1 ? atoi(argv[1]) : 8;

   // Set the PAD drive strength
   if (gpioSetPad(0, strength_ma) < 0) return 1; // GPIO 0-27
   if (gpioSetPad(1, strength_ma) < 0) return 1; // GPIO 28-45
   if (gpioSetPad(2, strength_ma) < 0) return 1; // GPIO 46-53

   gpioTerminate();

   return 0;
}

wiringpi.c

// gcc -Wall -O3 -pthread -o set_drive_strength wiringpi.c -lwiringPi

#include <stdlib.h>
#include <wiringPi.h>

int main(int argc, char *argv[]) {
   if (wiringPiSetup() < 0) return 1;

   int strength_ma = argc > 1 ? atoi(argv[1]) : 8;

   // 1-16 -> 0-7
   int pad_strength = strength_ma;
   pad_strength += 1;
   pad_strength /= 2;
   pad_strength -= 1;

   // Set the PAD drive strength
   setPadDrive(0, pad_strength & 7); // GPIO 0-27
   setPadDrive(1, pad_strength & 7); // GPIO 28-45
   setPadDrive(2, pad_strength & 7); // GPIO 46-53

   return 0;
}