ARM-linux嵌入式内核驱动——按键的驱动

/*************************************

按键的驱动，在TX2440A上做测试

维护记录： 2009-10-28 V1.0 

           2009-03-08 V1.1 

linux内核：2.6.31

硬件接法：

        KEY1 --> GPF4

        KEY2 --> GPF5

        KEY3 --> GPF6

        KEY4 --> GPF7

*************************************/

 

#include

#include

#include

#include

#include

#include

#include

#include

//#include

#include

//#include

#include

#include

#include

#include

 

#define BUFFER_SIZE 256

#define DEVICE_NAME  "TX2440-button" /* 设备名称 */

static int BUTTON_MAJOR  = 0;       /* 主设备号 */

 

static volatile int key_values [] = {0, 0, 0, 0};

static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

static volatile int ev_press = 0;

 

struct button_irq_desc

{

    int irq;

    int pin;

    int pin_setting;

    int number;

    char *name;  

};

 

/* 用来指定按键所用的外部中断引脚及中断触发方式, 名字 */

static struct button_irq_desc button_irqs [] =

{

    {IRQ_EINT4,   S3C2410_GPF(4),   S3C2410_GPF4_EINT4,  0, "KEY1"}, /* K1 */

    {IRQ_EINT5,   S3C2410_GPF(5),   S3C2410_GPF5_EINT5,  1, "KEY2"}, /* K2 */

    {IRQ_EINT6,   S3C2410_GPF(6),   S3C2410_GPF6_EINT6,  2, "KEY3"}, /* K3 */

    {IRQ_EINT7,   S3C2410_GPF(7),   S3C2410_GPF7_EINT7,  3, "KEY4"}, /* K4 */

};

 

static void open_irqs(void)

{

    int i;

   

    for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++)

    {

        enable_irq(button_irqs[i].irq);

    }

}

 

static void close_irqs(void)

{

    int i;

   

    for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++)

    {

        disable_irq(button_irqs[i].irq);

    }

}

 

static irqreturn_t buttons_interrupt(int irq, void *dev_id)

{

    struct button_irq_desc *button_irqs = (struct button_irq_desc *)dev_id;

    int key_press = s3c2410_gpio_getpin(button_irqs->pin);

 

    if (key_press == 0)

    {

        mdelay(20);

        key_press = s3c2410_gpio_getpin(button_irqs->pin);

        if (key_press == 0)

        {

            key_values[button_irqs->number] = (button_irqs->number + 1);

            ev_press = 1;

            wake_up_interruptible(&button_waitq);

        }          

    }

    return IRQ_RETVAL(IRQ_HANDLED);

}

 

static void register_irqsrv(void)

{

    int i;

    int err;

 

    for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++)

    {

        // 注册中断处理函数

        s3c2410_gpio_cfgpin(button_irqs[i].pin,button_irqs[i].pin_setting);

        err = request_irq(button_irqs[i].irq, buttons_interrupt, NULL, button_irqs[i].name, (void *)&button_irqs[i]);

        if (err)

            break;

    }

 

    if (err)

    {

        // 释放已经注册的中断

        i--;

        for (; i >= 0; i--)

        {

            disable_irq(button_irqs[i].irq);

            free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);

        }

        return -EBUSY;

    }  

}

 

static void unregister_irqsrv(void)

{

    int i;

   

    for (i = 0; i < sizeof(button_irqs)/sizeof(button_irqs[0]); i++)

    {

        free_irq(button_irqs[i].irq, (void *)&button_irqs[i]);

    }

}

 

static int TX2440_button_open(struct inode *inode, struct file *file)

{

    open_irqs();

    printk("TX2440-BUTTON Driver Open Called!\n");  

    return 0;

}

 

static int TX2440_button_close(struct inode *inode, struct file *file)

{

    close_irqs();

 

    printk("TX2440-BUTTON Driver Release Called!\n");   

    return 0;

}

 

static int TX2440_button_read(struct file *filp, char __user *buff, size_t count, loff_t *offp)

{

    unsigned long err;

 

    if (!ev_press)

    {

        if (filp->f_flags & O_NONBLOCK)

            return -EAGAIN;

        else

            wait_event_interruptible(button_waitq, ev_press);

    }

 

    ev_press = 0;

 

    err = copy_to_user(buff, (const void *)key_values, min(sizeof(key_values), count));

    memset((void *)key_values, 0, sizeof(key_values));

   

    return err ? -EFAULT : min(sizeof(key_values), count);

}

 

static unsigned int TX2440_button_poll( struct file *file, struct poll_table_struct *wait)

{

    unsigned int mask = 0;

    poll_wait(file, &button_waitq, wait);

    if (ev_press)

        mask |= POLLIN | POLLRDNORM;

    return mask;

}

 

static struct file_operations TX2440_button_fops =

{

    .owner =   THIS_MODULE,

    .open  =   TX2440_button_open,

    .release   =   TX2440_button_close,

    .read  =   TX2440_button_read,

    .poll  =   TX2440_button_poll,

};

 

static struct class *button_class;

 

static int __init TX2440_button_init(void)

{

    printk("TX2440 BUTTON DRIVER MODULE INIT\n");

   

    register_irqsrv();

    close_irqs();

 

    BUTTON_MAJOR = register_chrdev(0, DEVICE_NAME, &TX2440_button_fops);

    if (BUTTON_MAJOR < 0)

    {

        printk(DEVICE_NAME " can't register major number\n");

        return BUTTON_MAJOR;

    }

    printk("register TX2440-Button Driver OK! Major = %d\n", BUTTON_MAJOR);

 

    button_class = class_create(THIS_MODULE, DEVICE_NAME);

    if(IS_ERR(button_class))

    {

        printk("Err: failed in TX2440-Button class. \n");

        return -1;

    }

 

    device_create(button_class, NULL, MKDEV(BUTTON_MAJOR, 0), NULL, DEVICE_NAME);

 

    printk(DEVICE_NAME " initialized\n");

    return 0;

}

 

static void __exit TX2440_button_exit(void)

{

    printk("TX2440 BUTTON DRIVER MODULE EXIT\n");

   

    close_irqs();

    unregister_irqsrv();

   

    unregister_chrdev(BUTTON_MAJOR, DEVICE_NAME);

    device_destroy(button_class, MKDEV(BUTTON_MAJOR, 0));

    class_destroy(button_class);                   

}

 

module_init(TX2440_button_init);

module_exit(TX2440_button_exit);

 

MODULE_AUTHOR("www.txmcu.com");

MODULE_DESCRIPTION("TX2440 Button Driver");

MODULE_LICENSE("GPL");

 

源代码： TX2440_button.rar    

测试程序： key.rar