Hello World

/*按键设备中断触发，poll机制非阻塞，定时器使用方式*/
//keys 按键设备异步通知方式驱动文件 keys_async_drv.c 
#include <linux/module.h> 
#include <linux/kernel.h> 
#include <linux/fs.h> 
#include <linux/init.h> 
#include <linux/mutex.h> 
#include <linux/delay.h> 
#include <asm/uaccess.h> 
#include <asm/irq.h> 
#include <asm/io.h> 
#include <mach/hardware.h> 
#include <mach/regs-gpio.h> 
#include <linux/device.h> 
#include <linux/irq.h> 
#include <linux/interrupt.h> 
#include <linux/sched.h> 
#include <linux/timer.h> 
#include <linux/poll.h> 
//使用三星的 GPIO 库 API 
#include <plat/gpio-fns.h>
#include <mach/regs-gpio.h>

#define DEVICE_NAME "key_dev"

static struct class *key_irq_class;
static struct device *key_irq_device;
static DECLARE_WAIT_QUEUE_HEAD(key_waitq);
static struct timer_list key_timer;

static volatile int ev_press = 0;

struct pin_desc {
    unsigned int pin;
    unsigned int key_val;
};
struct  pin_desc pin_desc[] = {
    {S3C2410_GPF(0), 0x01},
    {S3C2410_GPF(2), 0x02},
    {S3C2410_GPF(3), 0x03},
    {S3C2410_GPF(11), 0x04},
};

struct pin_desc *pindesc = NULL;

static unsigned char key_val = 0;
/*按键中断服务函数*/
static irqreturn_t key_irq_handler(int irq, void *dev_id){
    pindesc = (struct pin_desc *)dev_id;
    /*启动定时器*/
    mod_timer(&key_timer, jiffies + msecs_to_jiffies(100));
    return IRQ_RETVAL(IRQ_HANDLED);
}

static int key_irq_open(struct inode *inode, struct file *file){
    int ret;
    /*配置引脚为中断功能*/
    s3c2410_gpio_cfgpin(S3C2410_GPF(0), S3C2410_GPF0_EINT0);
    s3c2410_gpio_cfgpin(S3C2410_GPF(2),  S3C2410_GPF2_EINT2);
    s3c2410_gpio_cfgpin(S3C2410_GPF(3), S3C2410_GPG3_EINT11);
    s3c2410_gpio_cfgpin(S3C2410_GPF(11),  S3C2410_GPG11_EINT19);

    /*请求中断*/
    ret = request_irq(IRQ_EINT0, key_irq_handler,  IRQ_TYPE_EDGE_BOTH, "key_irq_s2", (void *)&pin_desc[0]);
    if(ret < 0){
        printk("key_irq_s2 request_irq failed\n");
        return ret;
        }
    ret = request_irq(IRQ_EINT2, key_irq_handler, IRQ_TYPE_EDGE_BOTH, "key_irq_s3", (void *)&pin_desc[1]);
    if(ret < 0){
        printk("key_irq_s3 request_irq failed\n");
        return ret;
        }
    ret = request_irq(IRQ_EINT11, key_irq_handler, IRQ_TYPE_EDGE_BOTH, "key_irq_s4", (void *)&pin_desc[2]);
    if(ret < 0){
        printk("key_irq_s4 request_irq failed\n");
        return ret;
        }
    ret = request_irq(IRQ_EINT19, key_irq_handler, IRQ_TYPE_EDGE_BOTH, "key_irq_s5", (void *)&pin_desc[3]);
    if(ret < 0){
        printk("key_irq_s5 request_irq failed\n");
        return ret;
        }
    return 0;


    return 0;
}

static int key_irq_release(struct inode *inode, struct file *file){
   
     free_irq(IRQ_EINT0, (void *)&pin_desc[0]);

    free_irq(IRQ_EINT2, (void *)&pin_desc[1]);

    free_irq(IRQ_EINT11, (void *)&pin_desc[2]);

     free_irq(IRQ_EINT19, (void *)&pin_desc[3]);

    return 0;
}
static int key_irq_read(struct file *file, char __user *buf, size_t size, loff_t *offset){
    if(size != 1){
        return -EINVAL;
    }
    /*若是没有按键按下，则休眠*/
    wait_event_interruptible(key_waitq,ev_press);

    /*若有，则返回按键值*/

    if(copy_to_user(buf, (const void *)&key_val, 1)){
        printk("key_irq_read copy_to_user failed\n");
        return -EFAULT;
    }

    ev_press = 0;
    return 1;
}
/*非阻塞方式轮询*/
static unsigned key_irq_poll(struct file *file, poll_table *wait){
    unsigned int mask = 0;
    poll_wait(file, &key_waitq, wait);
    if(ev_press){
        mask |= POLLIN | POLLRDNORM;
    }
    return mask;
}

static struct file_operations key_irq_fops = {
    .owner = THIS_MODULE,
    .open = key_irq_open,
    .release = key_irq_release,
    .read = key_irq_read,
    .poll = key_irq_poll,
};

/*定时器超时处理函数*/
static void timer_handle(unsigned long data){
    unsigned int pinval;

    if(!pindesc) return;

    pinval = s3c2410_gpio_getpin(pindesc->pin);
    if(pinval){
        key_val = 0x08 | pindesc->key_val;
    }else{
        key_val = pindesc->key_val;
    }
    ev_press = 1;

    wake_up_interruptible(&key_waitq);

}


int major;

static int __init key_irq_init(void){ 
    major = register_chrdev(0, DEVICE_NAME, &key_irq_fops);
    if(major < 0){
        printk("key_irq_init register_chrdev failed\n");
        return major;
    }
    key_irq_class = class_create(THIS_MODULE, "keys_irq_drv");
    if(IS_ERR(key_irq_class)){
        unregister_chrdev(major, DEVICE_NAME);
        printk("key_irq_init class_create failed\n");
        return PTR_ERR(key_irq_class);
    }
    key_irq_device = device_create(key_irq_class, NULL, MKDEV(major, 0), NULL, DEVICE_NAME);
    if(IS_ERR(key_irq_device)){
        class_destroy(key_irq_class);
        unregister_chrdev(major, DEVICE_NAME);
        printk("key_irq_init device_create failed\n");
        return PTR_ERR(key_irq_device);
    }
    

    init_timer(&key_timer);
    key_timer.function = timer_handle;

    add_timer(&key_timer);

    printk("key_irq_init success\n");
    return 0;

}
    


static void __exit key_irq_exit(void){
    unregister_chrdev(major, DEVICE_NAME);
    device_destroy(key_irq_class, MKDEV(major, 0));
    class_destroy(key_irq_class);
    del_timer(&key_timer);
    printk("key_irq_exit success\n");
}


module_init(key_irq_init);
module_exit(key_irq_exit);

MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("key irq driver");