专题1-按键驱动程序设计-第6课-多按键驱动优化

1、概述

（1）多按键支持
（2）按键访问应用程序设计

 

2、编程

#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>
#define GPFCON 0x56000050
#define GPFDAT 0x56000054

struct work_struct *work1;
struct timer_list buttons_timer;
unsigned int *gpio_data;
unsigned int key_num;
void work1_func(struct work_struct *work)
{
    mod_timer(&buttons_timer, jiffies + (HZ /10));     
}
void buttons_timer_function(unsigned long data)  
{
    unsigned int key_val;
    
    key_val = readw(gpio_data)&0x1; 
    if (key_val == 0)
       key_num = 4;
    
    
    key_val = readw(gpio_data)&0x4;
    if (key_val == 0)
        key_num = 3;    
} 
irqreturn_t key_int(int irq, void *dev_id)
{
    //1. 检测是否发生了按键中断
    //2. 清除已经发生的按键中断
    //3. 提交下半部
    schedule_work(work1); 
    return IRQ_HANDLED;      
}
void key_hw_init()
{ 
    unsigned int *gpio_config;
    unsigned short data;  
    gpio_config = ioremap(GPFCON,4);
    data = readw(gpio_config);
    data &= ~0b110011;
    data |= 0b100010;
    writew(data,gpio_config);    
    gpio_data = ioremap(GPFDAT,4);
}
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)
{
    printk("in kernel :key num is %d\n",key_num);    
    copy_to_user(buf, &key_num, 4);

    return 4;
}

struct file_operations key_fops = 
{
    .open = key_open,
    .read = key_read,    
};

struct miscdevice key_miscdev = {
    .minor = 200,
    .name = "key",
    .fops = &key_fops,    
};

static int button_init()
{
    int ret;
    ret = misc_register(&key_miscdev);
    
    if (ret !=0)
        printk("register fail!\n");
    
    //注册中断处理程序
    request_irq(IRQ_EINT0,key_int,IRQF_TRIGGER_FALLING,"key",(void *)4);
    request_irq(IRQ_EINT2,key_int,IRQF_TRIGGER_FALLING,"key",(void *)3);
    
    //按键初始化
    key_hw_init();
    
    //. 创建工作
    work1 = kmalloc(sizeof(struct work_struct),GFP_KERNEL);
    INIT_WORK(work1, work1_func);
    
    /* 初始化定时器 */  
    init_timer(&buttons_timer);   
    buttons_timer.function  = buttons_timer_function;  
    
    /* 向内核注册一个定时器 */  
    add_timer(&buttons_timer);  
 
    return 0;  
}

static void button_exit()
{
    misc_deregister(&key_miscdev);    
}

module_init(button_init);
module_exit(button_exit);

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>

int main(int argc, char **argv)
{
    int fd;
    int key_num;
    fd = open("/dev/2440key", 0);   
    if (fd<0)
        printf("open fail\n");
    read(fd, &key_num, 4);
    printf("key is %d\n",key_num);
    close(fd);
    return 0;
}