Miscellany

/*
 * gpio.c: Simple program to configure/read/write GPIO's.
 *
 *  Copyright (C) 2003, Jamey Hicks <jamey.hicks@hp.com>
 *  Copyright (C) 2000, Jan-Derk Bakker (J.D.Bakker@its.tudelft.nl)
 *
 *
 * This software has been developed for the LART computing board
 * (http://www.lart.tudelft.nl/). The development has been sponsored by
 * the Mobile MultiMedia Communications (http://www.mmc.tudelft.nl/)
 * and Ubiquitous Communications (http://www.ubicom.tudelft.nl/)
 * projects.
 *
 * The author can be reached at:
 *
 *  Jan-Derk Bakker
 *  Information and Communication Theory Group
 *  Faculty of Information Technology and Systems
 *  Delft University of Technology
 *  P.O. Box 5031
 *  2600 GA Delft
 *  The Netherlands
 *
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 */

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <string.h>
#include <errno.h>
#include <signal.h>
#include <fcntl.h>
#include <ctype.h>
#include <termios.h>
#include <sys/types.h>
#include <sys/mman.h>

#define FATAL do { fprintf(stderr, "Error at line %d, file %s (%d) [%s]\n", \
  __LINE__, __FILE__, errno, strerror(errno)); exit(1); } while(0)

#define MAP_SIZE 4096UL
#define MAP_MASK (MAP_SIZE - 1)

int main(int argc, char **argv)
{
     int fd;
     volatile unsigned long *gpio_base;
     off_t gpio_nr;

     int dir = 0, set_dir = 0;
     int clear = 0, set = 0;

     if (argc < 2) {
          fprintf(stderr, "\nUsage:\t%s gpio\n",
                  argv[0]);
          exit(1);
     }
     int c = getopt_long(argc, argv, "cios", NULL, NULL);
     switch (c) {
     case 'c':
       clear = 1;
       break;
     case 'i':
       dir = 1;
       set_dir = 1;
       break;
     case 'o':
       dir = 0;
       set_dir = 1;
       break;
     case 's':
       set = 1;
       break;
     default:
       break;
     }
     gpio_nr = strtoul(argv[optind], 0, 0);

     if ((fd = open("/dev/mem", O_RDWR | O_SYNC)) == -1) FATAL;
     /* printf("/dev/mem opened.\n"); */
     fflush(stdout);

     /* Map one page */
     gpio_base = mmap(0, MAP_SIZE, PROT_READ | PROT_WRITE, MAP_SHARED,
                      fd, 0xc0804000 & ~MAP_MASK);
     if (gpio_base == (void *) -1) FATAL;

     if (clear) {
       printf("Clearing GPIO%d\n", gpio_nr);
       *(gpio_base + 0x0000) &= ~(1 << (gpio_nr&0x1f));
     }
     if (set) {
       printf("Setting GPIO%d\n", gpio_nr);
       *(gpio_base + 0x0000) |= (1 << (gpio_nr&0x1f));
     }
     if (set_dir) {
       if (dir) {
         *(gpio_base + 0x0004) |= (1 << (gpio_nr&0x1f));
         printf("GPIO%d is now an input\n", gpio_nr);
       }
       else {
         *(gpio_base + 0x0004) &= ~(1 << (gpio_nr&0x1f));
         printf("GPIO%d is now an output\n", gpio_nr);
       }
     }

     if (*(gpio_base + 0x0004) & (1 << (gpio_nr&0x1f))) {
       printf("GPIO%d is an input", gpio_nr);
       if (*(gpio_base + 0x0008) & (1 << (gpio_nr&0x1f))) {
         printf(" and is set\n");
       }
       else {
         printf(" and is cleared\n");
       }
     }
     else {
       printf("GPIO%d is an output", gpio_nr);
       if (*(gpio_base + 0x0000) & (1 << (gpio_nr&0x1f))) {
         printf(" and is set\n");
       }
       else {
         printf(" and is cleared\n");
       }
     }

     printf("GPOUTR = 0x%08x\n", *(gpio_base + 0x0000));
     printf("GPOER  = 0x%08x\n", *(gpio_base + 0x0004));
     printf("GPINR  = 0x%08x\n", *(gpio_base + 0x0008));
     printf("GPISR  = 0x%08x\n", *(gpio_base + 0x000c));
     printf("GPIT1R = 0x%08x\n", *(gpio_base + 0x0010));
     printf("GPIT2R = 0x%08x\n", *(gpio_base + 0x0014));
     printf("GPCLKR = 0x%08x\n", *(gpio_base + 0x0018));

     if (munmap((void *)gpio_base, MAP_SIZE) == -1) FATAL;
     close(fd);
     return 0;
}