#副標=Linux驅動程式系列(1)
#大標=Linux驅動程式整體架構
#眉標=Embedded Systems
#作者=文／陳俊宏



===========box 程式1============
int main(int argc, char *argv[])
{
  int devfd;

  devfd = open("/dev/debug", O_RDONLY);

  if (devfd == -1) {
	printf("Can't open /dev/debug\n");
	return -1;
    }

    ioctl(devfd, IOCTL_WRITE, num);

    close(devfd);

    return 0;
}

===============end==============




=========box 程式2===========
#define	DEV_MAJOR	121
#define	DEV_NAME	"debug"	
#define MSG(format, arg...) 
printk(KERN_INFO "DEBUG CARD: " format "\n", ## arg)

int init_module(void)
{
 MSG("DEBUG CARD v0.1.1");
 MSG("  Copyright (C) 2004 www.jollen.org");

 if (register_chrdev(DEV_MAJOR, DEV_NAME, &card_fops) < 0) 
 {
   MSG("Couldn't register a device.");
   return -1;
	}
    
	return 0;
}
================end=============




===========box 程式3==============
void cleanup_module(void)
{
    if (unregister_chrdev(DEV_MAJOR, DEV_NAME))
	MSG("failed to unregister driver");
    else
	MSG("driver un-installed\n");
}
===============end===========




========box 程式4=========
int card_open(struct inode *inode, struct file *filp)
{
	MOD_INC_USE_COUNT;
	return 0;
};
============end===========



=============box 程式5===========
int card_release(struct inode *inode, struct file *filp)
{
	MOD_DEC_USE_COUNT;
	kfree(filp->private_data);  //reentrant code 觀念

	return 0;
};
================end===============




=========box 程式6=========
unsigned long IOPort = 0x80;

void write_card(unsigned int num)
{
 MSG("write 0x%02X (%d) to debug card", 
 (unsigned char)num, num);
 outb((unsigned char)num, IOPort);
}

ssize_t card_write(struct file *filp, const char *buff, 
		size_t count, loff_t *offp)
{
	char *str;
	unsigned int num;
	int i;

	if (count == 0) return 0;

	filp->private_data = (char *)kmalloc(64, GFP_KERNEL);
	str = filp->private_data;

	if (copy_from_user(str, buff, count))
		return -EFAULT;

	/* atoi() */
	num = str[0]-'0'; for (i = 1; i < count; i++) {
		num = num*10 + (str[i]-'0');
	}

	write_card(num);

	return 1;
};

=============end==============