How to access the GPIO pins in AT91SAM9260-EK under Linux

[Sandeep G R <sandeep@xxxxxxxxxxxxxxxxxxxxx>]

Hi,

       I am using AT91SAM9260-EK in which linux is ported also i wrote  
some sample application under linux and compiled using arm toolchain  
now i want to access the GPIO pins for blinking the led on the board i  
have written the code and if i try to run the executable file in the  
target board it will give error as segmentation fault and below is the  
code please help us it would be great pleasure.


********LED***************/

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <sys/shm.h>

#include <sys/types.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <unistd.h>
#include <fcntl.h>
#include <strings.h>
#include <string.h>
#include <time.h>

#include "AT91SAM9260.h"

/* ********************** LOCAL DEFINES ****************************** */
#define    LED_MAX    2

/
static unsigned ledSignalMapping[] = {AT91C_PIO_PA6,AT91C_PIO_PA9};

#define    GPIO_LED_MASK (AT91C_PIO_PA6 | AT91C_PIO_PA9)


static int memMapFile;
static AT91PS_PIO at91SysCtrlr;

/* ************************ UTILITY FUNCTIONS  
******************************* */


/*
  * Set the LED output(s)
  */
static void UpdateLED(unsigned ledIndex, unsigned on)
{
     if (ledIndex >= LED_MAX)
         /* invalid index */
         return ;

     /* remember that LED signals are active low */
     if (on)
     {
         at91SysCtrlr->PIO_CODR = (ledSignalMapping[ledIndex]);
     }
     else
     {
         at91SysCtrlr->PIO_SODR = (ledSignalMapping[ledIndex]);
     }

}


/* *************** HARDWARE SUPPORT FUNCTIONS ************************ */


/*
  * Access the hardware
  */
static int OpenSystemController(void)
{
     if ((memMapFile = open("/dev/mem", O_RDWR | O_SYNC)) < 0)
     {
         printf("ERROR: Unable to open /dev/mem\n");
         return (errno);
     }

     at91SysCtrlr = mmap(NULL, 4096, PROT_READ | PROT_WRITE,
         MAP_SHARED, memMapFile, (unsigned)AT91C_BASE_SYS);

     if (at91SysCtrlr == MAP_FAILED)
     {
         printf("ERROR: Unable to mmap the system controller\n");
         close (memMapFile);
         memMapFile = -1;
         return (errno);
     }

     /* set LED signals for output */
     /* set digital output ports init value = all on (active low) */
     at91SysCtrlr->PIO_CODR    = GPIO_LED_MASK;
     at91SysCtrlr->PIO_PPUDR= GPIO_LED_MASK;
     at91SysCtrlr->PIO_PER    = GPIO_LED_MASK;
     at91SysCtrlr->PIO_OER    = GPIO_LED_MASK;


     return (0);
}


/* ************************ MAIN LOOPS ******************************* */


int main(int argc, char **argv)
{
     unsigned    ledIndex;


     if (OpenSystemController())
     {
         printf("Unable to map hardware resources\n");
         return (-1);
     }

     ledIndex = 0;
     while (1)
     {
         /* loop forever toggling LEDs at 1 second interval */

         /* turn on */
         UpdateLED(ledIndex, 1);
         printf ("LED %d is now on\n", ledIndex);

         /* wait for 0.5 seconds */
         usleep(500000);

         /* turn off */
         UpdateLED(ledIndex, 0);
         printf ("LED %d is now off\n", ledIndex);

         /* wait for 0.5 seconds */
         usleep(500000);

         /* reset index to first LED if we finished all of them */
         if (++ledIndex >= LED_MAX)
             ledIndex = 0;
     }

     return (0);
}


Sandeep G R,
Design Engineer,
Drass Mechatronics Pvt Ltd,
#304-5/M, Seetharam Industrial Estate,
MES Ring Road, Jalahalli,
Bangaalore-560013.
India






-------------------------------------------------------------------
List admin: http://lists.arm.linux.org.uk/mailman/listinfo/linux-arm
FAQ:        http://www.arm.linux.org.uk/mailinglists/faq.php
Etiquette:  http://www.arm.linux.org.uk/mailinglists/etiquette.php