按键控制led驱动

内核版本：linux2.6.22.6 硬件平台：JZ2440

驱动源码 key_drv.c ：

#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 *key_class;
static struct class_device *key_class_device;

volatile  unsigned long *GPFCON=NULL;
volatile  unsigned long *GPFDAT=NULL;
volatile  unsigned long *GPGCON=NULL;
volatile  unsigned long *GPGDAT=NULL;

static int key_drv_open(struct inode *inode,struct file *file)
{
  *GPFCON &= (~((0x03<<)|(0x03<<)));
  *GPGCON &= (~((0x03<<)|(0x03<<)));

   return ;
}

 ssize_t key_drv_read(struct file *file,const char __user *buf,size_t count,loff_t *ppos)
{
   unsigned char key_val[]={};
   unsigned long keyval=;

   if(count != sizeof(key_val)) return -EINVAL;

   keyval = *GPFDAT;
   key_val[] = (keyval & (<<))?: ;
   key_val[] = (keyval & (<<))?: ;

   keyval = *GPGDAT;
   key_val[] = (keyval & (<<))?: ;
   key_val[] = (keyval & (<<))?: ;

   copy_to_user(buf,key_val,sizeof(key_val));

   return sizeof(key_val);
}

static struct file_operations key_drv_mode=
{
    .owner = THIS_MODULE,
    .open = key_drv_open,
    .read = key_drv_read,
};

int major=;
static int key_drv_init(void)
{
    major = register_chrdev(,"key_drv",&key_drv_mode);

    key_class = class_create(THIS_MODULE,"key_class");
    key_class_device = class_device_create(key_class,NULL,MKDEV(major,),NULL,"key_devices");

    GPFCON=(volatile unsigned long *)ioremap(0x56000050,);
    GPFDAT=GPFCON+;
    GPGCON=(volatile unsigned long *)ioremap(0x56000060,);
    GPGDAT=GPGCON+;

    return ;
}

static void key_drv_exit(void)
{
   unregister_chrdev(major,"key_drv");

   class_device_unregister(key_class_device);
   class_destroy(key_class);
   iounmap(GPFCON);
   iounmap(GPGCON);

}

module_init(key_drv_init);
module_exit(key_drv_exit);
MODULE_LICENSE("GPL");

测试应用程序 key_drv_test.c ：

#include<sys/types.h>
#include<sys/stat.h>
#include<fcntl.h>
#include<stdio.h>

int main(int argc,char **argv)
{
   int fd=;
   int cnt=;
   unsigned char key_val[]={,,,};
   fd = open("/dev/key_devices",O_RDWR);
   if(fd <) printf("error: can't open device :/dev/key_devices");

   while()
       {
      read(fd,key_val,sizeof(key_val));
      if(!key_val[])  printf("key1 is down\n");
      if(!key_val[])  printf("key2 is down\n");
      if(!key_val[])  printf("key3 is down\n");
      if(!key_val[])  printf("key4 is down\n");
   }
return ;
}

Makefile文件:

KER_DIR=/work/systems/kernel/linux-/linux-2.6.22.6

all:
    make -C $(KER_DIR) M=`pwd` modules

clean:
    make -C $(KER_DIR) M=`pwd` modules clean
    rm -fr moudles.order

obj-m +=key_drv.o