lcdpower.c

基于linux和s3c2440的gpio驱动程序

//written by bcng xiyong,2007-7-1
//set gpj4 to zero to give a kill signal to chip ltc2950

//a guidline about how to use gpio_driver
//p[0] is the address of the iocon of the io
//p[1] is the bit place, from 0 to xx,
//for example, GPJ4, p[1] is 0x4;

//for write function, the 3th parameter, if the second bit is set,  them use keep before   

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <termios.h>
#include <unistd.h>

#define GPGCON 0x56000060
#define GPG4   0x4

int main(int argc,char *argv[])
{
   int fd,FunctionIndex,boolON=1;
   unsigned long  p[2];
   char *charon="on";
   
   if ((argc>2)||(argc<2))
   {
                printf("parameter error\n");
		return 0;
   }
   
   //printf("param  is %s\n",*(argv+1)); 	
   
   if ( !strcmp( *(argv+1),"on") ) boolON=1;
   else
   	if ( !strcmp( *(argv+1),"off") ) boolON=0;
   	else
   	{
                printf("parameter error\n");
		return 0;
        }
   
   fd=open("/dev/gpio",O_RDWR | O_NOCTTY);
   if (fd < 0)
        {
                printf("can not open gpio!\n");
		return 0;
        }

  p[0]=GPGCON;  //GPJCON
  p[1]=GPG4;
   
  
  if (boolON)
  {
   
      printf("Power on\n");
      write(fd,p,5);
  }
  else
  {
      printf("Power off\n");
      write(fd,p,0);
  }    
      
  return 1;
   
}