读取按键值驱动

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <asm/uaccess.h>

#include <asm/irq.h>

#include <asm/io.h>

#include <asm/arch/regs-gpio.h>

#include <asm/hardware.h>

static  struct  class *seconddrv_class;

static struct class_device *seconddrv_class_dev;

volatile   unsigned  long  *gpfcon;

volatile   unsigned  long  *gpfdat;

volatile   unsigned  long  *gpgcon;

volatile   unsigned  long  *gpgdat;

static  int second_drv_open(struct  inode  *inode,  struct  file  *file ) {

/*配置GPF0,2为输入引脚

*/ *

gpgcon &=~((0x3<< (0*2 )) | (0x3<<(2*2)));

/*配置GPF3,11为输入引脚 */

*gpfcon &=~((0x3<< (3*2 )) | (0x3<<(11*2)));

return 0;

}

ssize_t  second_drv_read (struct file *file, char __user *buf, size_t  size, loff_t *ppos) {

/*返回四个引脚的电平 */

unsigned  char key_vals[4];

int  regval;

if (size  !=  sizeof(key_vals))  

return -EINVAL;

/*读取GPF0,2*/

regval= *gpfdat;

key_vals [0]= ( regval & (1<<0) )  ?  1:0;

key_vals [1]= ( regval & (1<<2) )  ?  1:0;

/*读取GPF3,11*/

regval= *gpgdat;

key_vals [2]= ( regval & (1<<3) )  ?  1:0;

key_vals [3]= ( regval & (1<<11) )  ?  1:0;

copy_to_user(buf,  key_vals , sizeof(key_vals));

return sizeof(key_vals);

}

static  struct  file_operations  second_drv_fops= {

    .owner=THIS_MODULE,    

　.open = second_drv_open,          

  .read=  second_drv_read, };

int major;

static  int  second_drv_init() {

major=register_chrdev (0,  "second_drv",  & second_drv_fops);

seconddrv_class = class_create(THIS_MODULE, "seconddrv");  

/*if (IS_ERR(firstdrv_class))   

return PTR_ERR(firstdrv_class);*/

seconddrv_class_dev= class_device_create(seconddrv_class, NULL, MKDEV(major, 0), NULL, "buttons");

/*if (unlikely(IS_ERR(firstdrv_class_dev)))    

return PTR_ERR(firstdrv_class_dev);*/

gpfcon =(volatile unsigned long * )ioremap(0x56000050,16);             

gpfdat=gpfcon+1;

gpgcon =(volatile unsigned long * )ioremap(0x56000060,16);             

gpgdat=gpgcon+1;

return 0;

}

static  void  second_drv_exit() {

unregister_chrdev ( major,  "second_drv");

class_device_unregister(seconddrv_class_dev);    

class_destroy(seconddrv_class);  

iounmap(gpfcon);  

iounmap(gpgcon);

return 0;

}

module_init(second_drv_init);

module_exit(second_drv_exit);

MODULE_LICENSE("GPL");