阻塞型驱动设计

#include <linux/module.h>
#include <linux/init.h>
#include <linux/miscdevice.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/fs.h>
#include <asm/uaccess.h>
#include <linux/sched.h>


#define GPGCON 0x56000060
#define GPGDAT 0x56000064
unsigned int *gpio_config,*gpio_data;

/*定义工作项结构体*/
struct work_struct *work1;

/*定义定时器变量结构体*/
struct timer_list key_timer;

unsigned int key_num = 0;

/*定义等待队列*/
wait_queue_head_t key_queue;

#include "key.h"

/********************
函数名：work1_func
参数：无
返回值：无
函数功能：实现工作项
结构体中的func成员
********************/
void work1_func()
{
    /*启动定时器*/
    mod_timer(&key_timer,jiffies + (HZ/10));
}

/************************
函数名：que_init
参数：无
返回值：无
函数功能：创建一个工作项
*************************/
int que_init()
{
    /*创建工作*/
    work1 = kmalloc(sizeof(struct work_struct),GFP_KERNEL);

    INIT_WORK(work1, work1_func);
}

/************************
函数名：key_int
参数：无
返回值：0
函数功能：按键中断处理函数
*************************/
irqreturn_t key_int(int irq, void *dev_id)
{
    /*1、检测设备是否产生中断*/

    /*2、清除中断产生标志*/

    /*3、提交下半部分工作*/
    schedule_work(work1);

    return 0;
}

/************************
函数名：key_hw_init
参数：无
返回值：无
函数功能：初始化与按键相关
的寄存器
*************************/
void key_hw_init()
{
    unsigned int data; 
    gpio_config = ioremap(GPGCON,4);
    gpio_data = ioremap(GPGDAT,4);
    data = readw(gpio_config);
    data &= ((3)|(3<<6)|(3<<10)|(3<<12)|(3<<14)|(3<<22));//~(0b11);
    data |= (2|(2<<6)|(2<<10)|(2<<12)|(2<<14)|(2<<22));//0b10;
    writew(data,gpio_config);
}

/************************
函数名：key_timer_func
参数：无
返回值：无
函数功能：定时器超时处理函
数,达到规定时间执行此函数
*************************/
void key_timer_func()
{
    unsigned int key_val,i;

    for(i = 0;i < 15;i++)
    {
        if((i == 0)||(i == 3)||(i == 5)||(i == 6)||(i == 7)||(i == 11))
        {
            key_val = readw(gpio_data) & (1 << i);
            if(key_val == 0)
                key_num = i+1;
        }
    }
    wake_up(&key_queue);
}

int key_open(struct inode *node, struct file *filp)
{
    return 0; 
}

ssize_t key_read(struct file *filp, char __user *buf, size_t size, loff_t *pos)
{
    wait_event(key_queue,key_num);

    copy_to_user(buf,&key_num,4);

    /*清空按键键值*/
    key_num = 0;

    return 4;
}

/* 函数映射关系表*/
struct file_operations key_fops = 
{
    .open = key_open,
    .read = key_read,
    //.unlocked_ioctl = key_ioctl,
};

/*字符设备描述结构*/
struct miscdevice key_miscdev = 
{
    .minor = 200,
    .name = "key",
    .fops = &key_fops,
};

static int button_init()
{
    /*注册设备*/
    misc_register(&key_miscdev);

    /*硬件初始化*/
    key_hw_init();
    
    /*注册中断*/
    request_irq(IRQ_EINT8,key_int,IRQF_TRIGGER_FALLING ,"key",(void *) 0);
    request_irq(IRQ_EINT11,key_int,IRQF_TRIGGER_FALLING ,"key",(void *) 0);
    request_irq(IRQ_EINT13,key_int,IRQF_TRIGGER_FALLING ,"key",(void *) 0);
    request_irq(IRQ_EINT14,key_int,IRQF_TRIGGER_FALLING ,"key",(void *) 0);
    request_irq(IRQ_EINT15,key_int,IRQF_TRIGGER_FALLING ,"key",(void *) 0);
    request_irq(IRQ_EINT19,key_int,IRQF_TRIGGER_FALLING ,"key",(void *) 0);

    /*工作队列初始化*/
    que_init();

    /*初始化定时器*/

    init_timer(&key_timer);

    key_timer.function = key_timer_func;

    /*注册定时器*/
    add_timer(&key_timer);

    /*初始化等待队列*/
    init_waitqueue_head(&key_queue);

    printk("key.ko is ready\n");
    return 0;
}

static void button_exit()
{
    /*注销设备*/
    misc_deregister(&key_miscdev);
    /*注销中断*/
    free_irq(IRQ_EINT8, 0);
}

MODULE_LICENSE("GPL");
module_init(button_init);
module_exit(button_exit);

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

int main()
{
    int fd = 0,key_num;

    fd = open("/dev/mykey", O_RDWR);

    if(fd < 0)
        printf("open device fail!\n");

    read(fd, &key_num, 4);

    printf("key num is %d\n", key_num);

    close(fd);
　　
　　return 0;

}