字符设备驱动笔记——定时器防抖动（十）

1.定时器：
1).超时时间
2).处理函数

#include <linux/module.h>

#include <linux/kernel.h>

#include <linux/fs.h>

#include <linux/init.h>

#include <linux/delay.h>

#include <linux/irq.h>

#include <asm/uaccess.h>

#include <asm/irq.h>

#include <asm/io.h>

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

#include <asm/hardware.h>

#include <linux/poll.h>





static struct class 　　　　　　*sixthdrv_class;

static struct class_device    *sixthdrv_class_dev;



volatile unsigned long *gpfcon;

volatile unsigned long *gpfdat;



volatile unsigned long *gpgcon;

volatile unsigned long *gpgdat;



//定时器

static struct timer_list buttons_timer;





static DECLARE_WAIT_QUEUE_HEAD(button_waitq);



/* 中断事件标志, 中断服务程序将它置1，sixth_drv_read将它清0 */

static volatile int ev_press = 0;



static struct fasync_struct *button_async;





struct pin_desc{

    unsigned int pin;

    unsigned int key_val;

};





/* 键值: 按下时, 0x01, 0x02, 0x03, 0x04 */

/* 键值: 松开时, 0x81, 0x82, 0x83, 0x84 */

static unsigned char key_val;



struct pin_desc pins_desc[4] = {

    {S3C2410_GPF0, 0x01},

    {S3C2410_GPF2, 0x02},

    {S3C2410_GPG3, 0x03},

    {S3C2410_GPG11, 0x04},

};



static struct pin_desc *irq_pd;



//static atomic_t canopen = ATOMIC_INIT(1);     //定义原子变量并初始化为1



static DECLARE_MUTEX(button_lock);     //定义互斥锁



/*

  * 确定按键值

  */

static irqreturn_t buttons_irq(int irq, void *dev_id)

{

    /* 修改定时器的超时时间，10ms后启动定时器  HZ = 100*/

    irq_pd = (struct pin_desc *)dev_id;

    mod_timer(&buttons_timer, jiffies+HZ/100);

    return IRQ_RETVAL(IRQ_HANDLED);

}



static int sixth_drv_open(struct inode *inode, struct file *file)

{

#if 0    

    if (!atomic_dec_and_test(&canopen))

    {

        atomic_inc(&canopen);

        return -EBUSY;

    }

#endif        



    if (file->f_flags & O_NONBLOCK)

    {

        if (down_trylock(&button_lock))

            return -EBUSY;

    }

    else

    {

        /* 获取信号量 */

        down(&button_lock);

    }



    /* 配置GPF0,2为输入引脚 */

    /* 配置GPG3,11为输入引脚 */

    request_irq(IRQ_EINT0,  buttons_irq, IRQT_BOTHEDGE, "S2", &pins_desc[0]);

    request_irq(IRQ_EINT2,  buttons_irq, IRQT_BOTHEDGE, "S3", &pins_desc[1]);

    request_irq(IRQ_EINT11, buttons_irq, IRQT_BOTHEDGE, "S4", &pins_desc[2]);

    request_irq(IRQ_EINT19, buttons_irq, IRQT_BOTHEDGE, "S5", &pins_desc[3]);    



    return 0;

}



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

{

    if (size != 1)

        return -EINVAL;



    if (file->f_flags & O_NONBLOCK)

    {

        if (!ev_press)

            return -EAGAIN;

    }

    else

    {

        /* 如果没有按键动作, 休眠 */

        wait_event_interruptible(button_waitq, ev_press);

    }



    /* 如果有按键动作, 返回键值 */

    copy_to_user(buf, &key_val, 1);

    ev_press = 0;

    

    return 1;

}





int sixth_drv_close(struct inode *inode, struct file *file)

{

    //atomic_inc(&canopen);

    free_irq(IRQ_EINT0, &pins_desc[0]);

    free_irq(IRQ_EINT2, &pins_desc[1]);

    free_irq(IRQ_EINT11, &pins_desc[2]);

    free_irq(IRQ_EINT19, &pins_desc[3]);

    up(&button_lock);

    return 0;

}



static unsigned sixth_drv_poll(struct file *file, poll_table *wait)

{

    unsigned int mask = 0;

    poll_wait(file, &button_waitq, wait); // 不会立即休眠



    if (ev_press)

        mask |= POLLIN | POLLRDNORM;



    return mask;

}



static int sixth_drv_fasync (int fd, struct file *filp, int on)

{

    printk("driver: sixth_drv_fasync\n");

    return fasync_helper (fd, filp, on, &button_async);

}





static struct file_operations sencod_drv_fops = {

    .owner   =  THIS_MODULE,    /* 这是一个宏，推向编译模块时自动创建的__this_module变量 */

    .open    =  sixth_drv_open,     

    .read    =  sixth_drv_read,       

    .release =  sixth_drv_close,

    .poll    =  sixth_drv_poll,

    .fasync  =  sixth_drv_fasync,

};





int major;



static void buttons_timer_function(unsigned long data)

{

    struct pin_desc * pindesc = irq_pd;

    unsigned int pinval;



    if (!pindesc)

        return;

    

    pinval = s3c2410_gpio_getpin(pindesc->pin);



    if (pinval)

    {

        /* 松开 */

        key_val = 0x80 | pindesc->key_val;

    }

    else

    {

        /* 按下 */

        key_val = pindesc->key_val;

    }



    ev_press = 1;                  /* 表示中断发生了 */

    wake_up_interruptible(&button_waitq);   /* 唤醒休眠的进程 */

    

    kill_fasync (&button_async, SIGIO, POLL_IN);

}





static int sixth_drv_init(void)

{

    //定时器

    init_timer(&buttons_timer);

    buttons_timer.function = buttons_timer_function;

    //buttons_timer.expires  = 0;

    add_timer(&buttons_timer); 



    major = register_chrdev(0, "sixth_drv", &sencod_drv_fops);



    sixthdrv_class = class_create(THIS_MODULE, "sixth_drv");



    /* 为了让mdev根据这些信息来创建设备节点 */

    sixthdrv_class_dev = class_device_create(sixthdrv_class, NULL, MKDEV(major, 0), NULL, "buttons"); /* /dev/buttons */



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

    gpfdat = gpfcon + 1;



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

    gpgdat = gpgcon + 1;



    return 0;

}



static void sixth_drv_exit(void)

{

    unregister_chrdev(major, "sixth_drv");

    class_device_unregister(sixthdrv_class_dev);

    class_destroy(sixthdrv_class);

    iounmap(gpfcon);

    iounmap(gpgcon);

    return 0;

}





module_init(sixth_drv_init);



module_exit(sixth_drv_exit);



MODULE_LICENSE("GPL");

2.测试程序

#include <sys/types.h>

#include <sys/stat.h>

#include <fcntl.h>

#include <stdio.h>

#include <poll.h>

#include <signal.h>

#include <sys/types.h>

#include <unistd.h>

#include <fcntl.h>





/* sixthdrvtest 

  */

int fd;



void my_signal_fun(int signum)

{

    unsigned char key_val;

    read(fd, &key_val, 1);

    printf("key_val: 0x%x\n", key_val);

}



int main(int argc, char **argv)

{

    unsigned char key_val;

    int ret;

    int Oflags;



    //signal(SIGIO, my_signal_fun);

    

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

    if (fd < 0)

    {

        printf("can't open!\n");

        return -1;

    }



    //fcntl(fd, F_SETOWN, getpid());

    

    //Oflags = fcntl(fd, F_GETFL); 

    

    //fcntl(fd, F_SETFL, Oflags | FASYNC);





    while (1)

    {

        ret = read(fd, &key_val, 1);

        printf("key_val: 0x%x, ret = %d\n", key_val, ret);

        //sleep(5);

    }

    

    return 0;

}