small_keyboard.c

自行开发的uclinux系统4x4键盘的底层驱动

#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/uaccess.h>
#include <linux/interrupt.h>
#include <linux/sched.h>
#include <asm/irq.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/sched.h>
#include <linux/kernel_stat.h>
#include <linux/errno.h>
#include <linux/init.h>
#include <linux/seq_file.h>

#include <asm/system.h>
#include <asm/page.h>
#include <asm/nios.h>
#include <asm/hardirq.h>

#define DEVICE_FILE_NAME "/dev/small_keyboard"
#define DEVICE_NAME "small_keyboard"
#define MAJOR_NUM	251
#define SUCCESS 0

static int keyboard = 0;
static int keyboard_value=-1;

unsigned long int Read(unsigned long int add)
{      
    unsigned char value;
    unsigned long int  *addr,data;
    
    addr=(unsigned long int*)(add);
    
    data=*addr;
    
    value=(unsigned char)data;
    
    return(value);
}

void Write(unsigned long int add,unsigned char  data)
{
   unsigned long int *addr;
   unsigned char datain;
           
    addr=(unsigned long int*)(add);
    datain=(unsigned char)data; 
    
    *addr=datain;
    
}


static irqreturn_t gpio_irq_handler(int irq, void *dev_id,struct pt_regs *reg)
{
	unsigned char value;
 /*  unsigned char key[16];
   int i;
        
 printk("get the IRQ2\n");
	value=Read(0x02010870);
	printk("take off IRQ2\n");
   value=Read(0x02010871);
  key[0]=0x8f;
   key[1]=0x1f;
   key[2]=0x5f;
   key[3]=0xf1;
   key[4]=0x2f;
   key[5]=0x6f;
   key[6]=0x9f;
   key[7]=0x3f;
   key[8]=0x7f;
   key[9]=0x0f;
   key[10]=0x4f;
   key[11]=0xf5;
   key[12]=0xf6;
   key[13]=0xf4;
   key[14]=0xf3;
   key[15]=0xf2;
   key[16]='\0';
   for(i=0;i<16;)
         {
     if(value==key[i++])
        break;
         }  
   keyboard_value=i-1;
   printk("key=%d\n",keyboard_value);*/
	printk("get the IRQ2\n");
	value=Read(0x02010870);
	printk("take off IRQ2\n");
  value=Read(0x02010871);
  printk("value is 0x%02lx.\n",value);
 	return 0;
}


/*
 * Function 1:device_open
 */
static int keyboard_open(struct inode *inode, struct file *file)
{ 
  if (keyboard)
    return -EBUSY;
  
  keyboard++;

  try_module_get(THIS_MODULE);
  return SUCCESS;
}

/*
 * Function 2:device_release
 */
static int keyboard_release(struct inode *inode, struct file *file)
{  
  keyboard--;
  free_irq(2, NULL);
  module_put(THIS_MODULE);
  return SUCCESS;
}

/*
 * Function 3:device_read
 */
static ssize_t keyboard_read(struct file *file,char __user * buffer,size_t length,loff_t * offset)
{
   int i=keyboard_value;
   keyboard_value=-1;
   printk("i=%d\n",i);   
   return i;
}

struct file_operations Keyboard_Fops = 
{
  .read = keyboard_read,
  .open = keyboard_open,
  .release = keyboard_release,	
};

int __init ite_gpio_init(void)
{
  int ret_val;
  ret_val = register_chrdev(MAJOR_NUM, DEVICE_NAME, &Keyboard_Fops);
  if (ret_val < 0) {
    printk(KERN_ALERT "%s failed with %d\n",
	   "Sorry, registering the character device ", ret_val);
    return ret_val;
     }
  if (request_irq(2, gpio_irq_handler, 0, DEVICE_NAME, NULL)) {
		printk("IRQ2 request error!\n");
		return 0;
	}
  printk("IRQ2 request success!\n");
  printk(KERN_INFO "Device %s registered\n", DEVICE_FILE_NAME);
  return 0;

}

static void __exit ite_gpio_exit(void)
{
  int ret; 
  ret = unregister_chrdev(MAJOR_NUM, DEVICE_NAME);  
  if (ret < 0)
    printk(KERN_ALERT "Error: unregister_chrdev: %d\n", ret);
}



module_init(ite_gpio_init);
module_exit(ite_gpio_exit);

#define author "HLT of TCB: Department 2"
#define description "A driver for small keyboard device of the satellite project."
MODULE_AUTHOR(author);
MODULE_DESCRIPTION(description);
MODULE_SUPPORTED_DEVICE(DEVICE_NAME);
MODULE_LICENSE("GPL");