Odroid XU4 GPA0.2(#173) toggle/ does not working. todo: fix error

main.c

#include <stdio.h>
#include <fcntl.h>
#include <sys/mman.h>
#include <stdint.h>

// Toggle GPA0.2
// Pinmap http://odroid.com/dokuwiki/doku.php?id=en:xu4_shift_shield
#define ODROIDXU_GPA_BASE   0x14010000

static volatile uint32_t *gpio;

int main(int argc, char **argv)
{
        int fd ;

        if ((fd = open ("/dev/mem", O_RDWR | O_SYNC) ) < 0) {
                printf("Unable to open /dev/mem\n");
                return -1;
        }

        gpio = mmap(0, getpagesize(), PROT_READ|PROT_WRITE, MAP_SHARED, fd,     ODROIDXU_GPA_BASE);

        if (gpio < 0){
                printf("Mmap failed.\n");
                return -1;
        }

        // Print GPA0BASE
        //printf("GPA0BASE: 0x%08x\n", (unsigned int)(gpio));

        // Set direction of GPA0.2 configuration register as out.
        *(gpio + 0)  |= (0x1 << 8);
        //printf("GPA0CON register : 0x%08x\n", *(unsigned int *)(gpio));

        while(1) {
                //// GPA0.2 High
                *(gpio + 1) |= (0x1 << 2);
                //printf("GPA0DAT register : 0x%08x\n", *(unsigned int *)(gpio + 1));

                // GPA0.2 Low
                *(gpio + 1) &= ~(0x1 << 2);
                //printf("GPA0DAT register : 0x%08x\n", *(unsigned int *)(gpio + 1));
        }


        return 0;
}