eintdrv.c

ARM开发实例emed linuxexamples.tar.gz

/*  leddrv.c - Create an input/output character device
 */

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/errno.h> 	/* for -EBUSY */
#include <linux/ioport.h>	/* for verify_area */
#include <linux/init.h>		/* for module_init */
#include <asm/uaccess.h>  	/* for get_user and put_user */
#include <asm/irq.h>
#include <asm-arm/arch-s3c2410/S3C2410.h>

#include "eintdrv.h"

#define 	DEBUG

#ifdef  	DEBUG
#define 	DbgPrintk(S)	printk (S)
#else
#define 	DbgPrintk(S)		
#endif
	
#define 	BUF_LEN 		4
#define 	DEVICE_NAME 	"int_dev"

static int 	Device_Open = 0;
static char Message[BUF_LEN];
static char *Message_Ptr;

int 	device_ioctl(struct inode *,struct file *,unsigned int ,unsigned long ); 	

static void eint2_handler(int irq, void *dev_id, struct pt_regs *regs)
{
        printk("\rextern irq 2 handled");
}
                                                                                                                                               
/* This function is called whenever a process attempts 
 * to open the device file */
static int device_open(struct inode *inode, struct file *file)
{
  int eint_irq;
  int ret_val;

  DbgPrintk(("'/dev/eint' device open\n"));

  /* We don't want to talk to two processes at the 
   * same time */
  if (Device_Open) return -EBUSY;

  Device_Open++;
  
  /* register the eint2 irq */
  eint_irq = IRQ_EINT2;
  set_external_irq(eint_irq, EXT_FALLING_EDGE, GPIO_PULLUP_DIS);
  ret_val = request_irq(eint_irq, eint2_handler, 0, "s3c2410 eint 2", 0);
  if (ret_val < 0) {
           return ret_val;
  }

  MOD_INC_USE_COUNT;

  /* Initialize the message */
  Message_Ptr = Message;

  return 0;
}

/* This function is called when a process closes the 
 * device file. It doesn't have a return value because 
 * it cannot fail. Regardless of what else happens, you 
 * should always be able to close a device (in 2.0, a 2.2
 * device file could be impossible to close).
 */
static int device_release(struct inode *inode, struct file *file)
{
  DbgPrintk(("'/dev/eint' device release\n"));

  /* We're now ready for our next caller */
  Device_Open --;

  MOD_DEC_USE_COUNT;

  return 0;
}

/* Module Declarations *************************** */
/* This structure will hold the functions to be called 
 * when a process does something to the device we 
 * created. Since a pointer to this structure is kept in 
 * the devices table, it can't be local to
 * init_module. NULL is for unimplemented functions. */
struct file_operations Fops = {
	.open 		= device_open,
	.release 	= device_release,
	};

/* Initialize the module - Register the character device */
static int __init eint_module_init( void )
{
    	int ret_val;
  
  	/* Register the character device (atleast try) */
  	ret_val = register_chrdev(MAJOR_NUM, DEVICE_NAME, &Fops);

  	/* Negative values signify an error */
  	if (ret_val < 0) {
    		printk ("%s failed with %d\n",
            		"Sorry, registering the character device ",
            		ret_val);
    	return ret_val;
  	}

  	printk ("%s The major device number is %d.\n",
          	"Registeration is a success", 
          	MAJOR_NUM);
          
	printk ("If you want to talk to the device driver,\n");
  	printk ("you'll have to create a device file. \n");
  	printk ("We suggest you use:\n");
  	printk ("mknod %s c %d 0\n", DEVICE_FILE_NAME,MAJOR_NUM);
  	printk ("The device file name is important, because\n");
  	printk ("the ioctl program assumes that's the\n");
  	printk ("file you'll use.\n");

  	return 0;
};

/* Cleanup - unregister the appropriate file from /proc */
static void __exit eint_module_cleanup(void)
{
  int ret;
  
  /* free irqs */
  free_irq(IRQ_EINT2,"s3c2410 eint 2");
 
  /* Unregister the device */
  ret = unregister_chrdev(MAJOR_NUM, DEVICE_NAME);
 
  /* If there's an error, report it */ 
  if (ret < 0)
    printk("Error in module_unregister_chrdev: %d\n", ret);
};

module_init(eint_module_init);
module_exit(eint_module_cleanup);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Cvtech Co., Ltd <http://www.cvtech.com.cn>");
MODULE_DESCRIPTION("EINT char driver");