雑誌インターフェース 2012年12月号のGPIO制御のコードがRev1用みたいだったのでRev2用に修正。 また、GPIO4がなぜか無効になっていた(何故かはよくわからない)ので使えるようにした。

gpio_c.c

//
//  How to access GPIO registers from C-code on the Raspberry-Pi
//  Example program
//  15-January-2012
//  Dom and Gert
//


// Access from ARM Running Linux

#define BCM2708_PERI_BASE        0x20000000
#define GPIO_BASE                (BCM2708_PERI_BASE + 0x200000) /* GPIO controller */


#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <dirent.h>
#include <fcntl.h>
#include <assert.h>
#include <sys/mman.h>
#include <sys/types.h>
#include <sys/stat.h>

#include <unistd.h>

#define PAGE_SIZE (4*1024)
#define BLOCK_SIZE (4*1024)

int  mem_fd;
char *gpio_mem, *gpio_map;
char *spi0_mem, *spi0_map;


// I/O access
volatile unsigned *gpio;


// GPIO setup macros. Always use INP_GPIO(x) before using OUT_GPIO(x) or SET_GPIO_ALT(x,y)
#define INP_GPIO(g) *(gpio+((g)/10)) &= ~(7<<(((g)%10)*3))
#define OUT_GPIO(g) *(gpio+((g)/10)) |=  (1<<(((g)%10)*3))
#define SET_GPIO_ALT(g,a) *(gpio+(((g)/10))) |= (((a)<=3?(a)+4:(a)==4?3:2)<<(((g)%10)*3))

#define GPIO_SET *(gpio+7)  // sets   bits which are 1 ignores bits which are 0
#define GPIO_CLR *(gpio+10) // clears bits which are 1 ignores bits which are 0
#define GPIO_GET *(gpio+13) // read   bits

#define REV2 // for rev2 board
#ifdef REV2
#define  MAX_PORTNUM	27
char valid_port[] = {
 0,0,1,1, // 0..3
 1,0,0,1, // 4..7
 1,1,1,1, // 8..11
 0,0,1,1, // 12..15
 0,1,1,0, // 16..19
 0,0,1,1, // 20..23
 1,1,0,1, // 24..27
};
#else
#define	MAX_PORTNUM	25
char valid_port[] = {
 1,1,0,0,
 0,0,0,1,
 1,1,1,1,
 0,0,1,1,
 0,1,1,0,
 0,1,1,1,
 1,1
};
#endif

void setup_io();

int port_avail(int port)
{
	if ((port < 0) || (port > MAX_PORTNUM))
		return (0);
	return ((int)valid_port[port]);
}

int gpio_read(int port)
{
	if (!port_avail(port))
		return(0);
	return( (GPIO_GET & (1<<port)) ? 1 : 0);
}

void gpio_write(int port, int data)
{
	if (!port_avail(port)) {
        printf("illigal port:%d\n", port);
		return;
    }
	if (data == 0)
		GPIO_CLR = 1<<port;
	else
        GPIO_SET = 1<<port;
}

//
// Set up a memory regions to access GPIO
//
int initcount= 0;
void setup_io()
{
	initcount++;
   /* open /dev/mem */
   if ((mem_fd = open("/dev/mem", O_RDWR|O_SYNC) ) < 0) {
      printf("can't open /dev/mem \n");
      exit (-1);
   }

   /* mmap GPIO */

   // Allocate MAP block
   if ((gpio_mem = malloc(BLOCK_SIZE + (PAGE_SIZE-1))) == NULL) {
      printf("allocation error \n");
      exit (-1);
   }

   // Make sure pointer is on 4K boundary
   if ((unsigned long)gpio_mem % PAGE_SIZE)
     gpio_mem += PAGE_SIZE - ((unsigned long)gpio_mem % PAGE_SIZE);

   // Now map it
   gpio_map = (char *)mmap(
      (caddr_t)gpio_mem,
      BLOCK_SIZE,
      PROT_READ|PROT_WRITE,
      MAP_SHARED|MAP_FIXED,
      mem_fd,
      GPIO_BASE
   );

   if ((long)gpio_map < 0) {
      printf("mmap error %d\n", (int)gpio_map);
      exit (-1);
   }

   // Always use volatile pointer!
   gpio = (volatile unsigned *)gpio_map;


} // setup_io

void gpio_init()
{
	int i;
	setup_io();
#if 1 // modify. test gpio4
    INP_GPIO(4); // must use INP_GPIO before we can use OUT_GPIO
    OUT_GPIO(4);
#else
    for (i=0; i<1; i++) {
		INP_GPIO(i);
	}
	for (i=7; i<=11; i++) {
		INP_GPIO(i); // must use INP_GPIO before we can use OUT_GPIO
		OUT_GPIO(i);
	}
#endif
}


void testmain()
{
#if 1 // modify. test gpio4
    int i;
    for(i = 0; i < 10; i++) {
        gpio_write(4, 1);
        sleep(1);
        gpio_write(4, 0);
        sleep(1);
    }
#else
    int p;
    for (p=7; p<=11; p++) {
       gpio_write(p,1);
	sleep(1);
     }
     for (p=0; p<2; p++) {
	printf("%d:",gpio_read(p));
     }
     printf("\n");
     for (p=7; p<=11; p++) {
       gpio_write(p,0);
       sleep(1);
     }
     for (p=0; p<2; p++) {
	printf("%d:",gpio_read(p));
     }
     printf("\n");
#endif
}

int main(int argc, char **argv)
{ 
 
	gpio_init();
	testmain();
	return 0;
} // main