my_key.c

这个是Linux下的按键驱动程序

#include <linux/kernel.h>
#include <linux/module.h>
                                                                                
#if CONFIG_MODVERSIONS==1
#define MODVERSIONS
#include <linux/modversions.h>
#endif
#include <linux/fs.h>
#include <linux/wrapper.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <asm/segment.h>
#include <asm/hardware.h>
#include <asm/arch/s3c2410.h>	
#include <asm/irq.h>
                                                                                
#ifndef KERNEL_VERSIONS
#define KERNEL_VERSIONS(a,b,c) ((a)*65536+(b)*256+(c))
#endif
                                                                                
#if LINUX_VERSION_CODE > KERNEL_VERSION(2,2,0)
#include <asm/uaccess.h>
#endif
#define SUCCESS 0
                                                                                
#define DEVICE_NAME "my_key"


static unsigned char  key_value;

void key_init(void)
{
#if 0
	rGPCCON &= 0xfffff0c3;                  //potr c 1 2 3 4 input
#else
	rGPCCON &= 0xfffffc03;
#endif
        //0xfffffc03
	//rGPCDAT = port data
	//rGPCUP = pull ip
	rGPGCON &= 0xffffc30f;			//port g 2 3 5 6 input
	//rGPGDAT = port data
	//rGPGUP = port up
}

static ssize_t mykey_read(struct file * file, char * buf, size_t count, loff_t *ppos )
{
  //ssize_t ret;
  /*if((rGPCDAT & 0x0020) == 1)
  {
     *buf |= 0x0002;
  }
  else
  {
     *buf &= 0xfffd;
  }*/
  *buf = ((rGPCDAT >> 1) | (rGPGDAT << 2) | (rGPGDAT & 0x40));
#if 0
  if((rGPCDAT & 0x0010) == 1)
  {
     *buf |= 0x0002;
  }
  else
  {
     *buf &= 0xfffd;
  }
#endif
  if(copy_to_user(&key_value,buf,sizeof(key_value)))
  {
      printk("key.c:write data error\n");
      return -EFAULT;
  }
  return 0;
}
static int mykey_open( struct inode *inode, struct file *file )
{
   //module_speak();
   key_init();
   printk("device_open(%p,%p)\n",inode,file);
   //Message_Ptr=Message;
   MOD_INC_USE_COUNT;
   return SUCCESS;
}
static int mykey_release( struct inode *inode, struct file *file )
{
   	//module_speak();
         printk("device_release(%p,%p)\n",inode,file);
         MOD_DEC_USE_COUNT;
         return 0;
}
static int Major;
struct file_operations Fops={
        llseek:NULL,
        read:mykey_read,
        write:NULL,
        readdir:NULL,
        ioctl:NULL,
        mmap:NULL,
        open:mykey_open,
        release:mykey_release,
};

int init_module()
{
        //int ret_val;
        //int t;
	Major=register_chrdev(0,DEVICE_NAME,&Fops);
	//printk("register interrupt fig=%d\n",t);
	printk("my_key.c:register OK:The major is %d\n",Major);
                                                                                
        return 0;
}
void cleanup_module()
{
        int ret;
                                                                                
        ret=unregister_chrdev(Major,DEVICE_NAME);
        printk("my_key.c:unregister OK\n");
                                                                                
}