keyboard.c

用于Linux 2.4内核的LCD及键盘驱动

#ifndef __KERNEL__
#define __KERNEL__
#endif

#ifndef MODULE
#define MODULE
#endif

#include <linux/kernel.h>
#include <linux/module.h>
#include <asm/uaccess.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/ioport.h>
#include <asm/io.h>
#include <asm/8xx_immap.h>

/*
* Header files for the charcater device 
*/
#include <linux/fs.h>
#include <linux/wrapper.h>


//#define DEBUG

#define SUCCESS      0		/*function successfully return */
#define DEVICE_NAME "keyboard"	/*define lcd device name */
#define LCD_MAJOR   189		/*define the lcd device major number */

/*
*Set led control 
*/
#define LED_ADDR 0x8000001b
#define LED_OFF  0xff
#define LED_ON  0x80

#define KEYBOARD_BASE  0x80000000
#define KEYBOARD_ROW_ADDR 0x8000001d
#define KEYBOARD_COL_ADDR 0x80000017


/*
*Define bit-swap operations
*/
#define S_B7(x) (((x) & 0x80)>>7)
#define S_B6(x) (((x) & 0x40)>>5)
#define S_B5(x) (((x) & 0x20)>>3)
#define S_B4(x) (((x) & 0x10)>>1)
#define S_B3(x) (((x) & 0x08)<<1)
#define S_B2(x) (((x) & 0x04)<<3)
#define S_B1(x) (((x) & 0x02)<<5)
#define S_B0(x) (((x) & 0x01)<<7)
#define BIT_SWAP(x) (S_B7(x) | S_B6(x)|S_B5(x) | S_B4(x)| S_B3(x)                                 | S_B2(x)| S_B1(x)| S_B0(x))


static int device_open_num = 0;	/*record numbers oflcd device opening by usr */
static int Major;		/*the lcd device major number */

/*
*Standard device_driver function prototypes declaratioins
*/
static int device_open (struct inode *, struct file *);
static int device_release (struct inode *, struct file *);
static ssize_t device_read (struct file *, const char *, size_t, loff_t *);


/*
*Standard moudle functions prototypes declarations
*/
int init_module (void);
void cleanup_module (void);

struct file_operations lcd_ops = {
read:device_read,
open:device_open,
release:device_release,
};


/*
*Initialize the driver -Register the character device
*/

static int
keyboard_init (void)
{

  int ret;
  // init_mem ();
  /*
   *Register the character device -lcd
   */

  ret = register_chrdev (keyboard_MAJOR, DEVICE_NAME, &lcd_ops);

  /* register lcd device faild */
  if (ret < 0)
    {

      iounmap ((void *) virt_base);
      printk ("Lcd init_module register failed 
          with %d\n major number\n", Major);
      return Major;
    }

  /*register successed */
  Major = LCD_MAJOR;
  printk ("Lcd register major number :%d successed\n", Major);

  /*
   *Lcd function initial
   */

  writeb (LED_OFF, LED_ADDR);	/*turn off led */
  return SUCCESS;
}


}

/***************************************************
****Standard  driver operation functions***********
**************************************************/

/*
*Called whenever a process attempt to open the lcd device
*/

static int
device_open (struct inode *inode, struct file *lcd_device_file)
{

#ifdef DEBUG
  //  printk (DEVICE_NAME "%d.%d open", inode->i_rdev >> 8, inode->iredv & 0xff);
#endif
  if (device_open_num)		/*ensure open lcd device exclusively */
    {
      return -EBUSY;		/*lcd device has been open by other process */
    }

  /*
   *Make sure that this module isn't removed while
   *the lcd is open by increasing the lcd usage count
   */
  if (check_region (LCD_BASE, 0x1ff))
    {
      printk ("%s memory already in use\n", DEVICE_NAME);
      return -EBUSY;
    }



  device_open_num++;
  MOD_INC_USE_COUNT;
  lcd_set (DISPLAY_CLEAR);
  lcd_set (INPUT_MODE_SET);
  return SUCCESS;

}

/*
*Called whenever a process closes the lcd device
*/
static int
device_release (struct inode *inode, struct file *lcd_device_file)
{
#ifdef DEBUG
  //  printk (DEVICE_NAME "%d.%d closed", inode->i_rdev >> 8,
  //      inode->iredv & 0xff);
#endif
  /*
   *Make sure that this module isn't removed while
   *the lcd is open by increasing the lcd usage count
   */
  device_open_num--;
  MOD_DEC_USE_COUNT;

  return SUCCESS;
}

/*
*The Lcd device driver write function
*/

static ssize_t
device_write (struct file *lcd_device_file, 
	      const char *buffer, /*buffer for data outputed to lcd */
	      size_t length,	/*length of buffer */
	      loff_t * offset)	/*file pointer offset */
{
   return SUCCESS;
}


/***********************************
**** Linux Module functions*********
***********************************/

#ifdef MOUDLE

/*
*Initialize the lcd device driver module
*/
int
init_module (void)
{
  return keyboard_init ();
}

/*
*Cleanup the lcd device driver moudle
*/

void
cleanup_module ()
{
  int ret;
#ifdef DEBUG
  printk ("I realse myself from kernel\n");
#endif
  /*unmap memory*/ 
  iounmap ((void *) virt_base);

  /* Unregister the device */
  ret = unregister_chrdev (Major, DEVICE_NAME);
  if (ret < 0)
    {
      printk ("unregister char_dev :error%d\n", ret);
    }
  
  lcd_set(DISPLAY_OFF);
  lcd_set (DISPLAY_CLEAR);
  writeb (LED_ON, LED_ADDR);	/*turn on led */
}

#endif /*MODULE*/