输入设备驱动之按键设备驱动

1.  
    #include<linux/module.h>
    #include<linux/kernel.h>
    #include<linux/init.h>
    #include<linux/types.h>
    #include<linux/slab.h>
    #include<linux/string.h>
    #include<linux/input.h>
    #include<linux/irq.h>
    #include<mach/gpio.h>
    #include<mach/regs-gpio.h>
    #include<asm/irq.h>
    #include<asm/io.h>
    #include<linux/interrupt.h>
    #include<linux/delay.h>

    #define DEVICE_NAME    "TQ2440_BUTTON"

    #define NUMBERS_BUTTONS        4

    static const char * input_name = "Tq2440_button";

    static struct input_dev *button_dev;

    /*中断集合*/
    static const int irqs[NUMBERS_BUTTONS]={
        IRQ_EINT0,
        IRQ_EINT1,
        IRQ_EINT2,
        IRQ_EINT4,
    };

    /*端口集合*/
    static const int gpios[NUMBERS_BUTTONS]={
        S3C2410_GPF0,
        S3C2410_GPF1,
        S3C2410_GPF2,
        S3C2410_GPF4,
    };
    /*事件代号集合*/
    static const int keys[NUMBERS_BUTTONS]={
        KEY_1,
        KEY_2,
        KEY_3,
        KEY_4,
    };

    /*中断处理程序*/

    static irqreturn_t button_interrupt(int irq,void * p)
    {
        int val = 0, i= 0;
        for(i = 0; i < NUMBERS_BUTTONS; ++ i)
        {
            /*如果中断号正确*/
           
            if(irqs[i] == irq)
            {
                /*读取端口的值*/
               
                val = s3c2410_gpio_getpin(gpios[i]);
                /*汇报端口的值，实质上是将事件key[i]汇报*/
               
                input_report_key(button_dev,keys[i],val);
                /*汇报同步，也就是完成汇报工作*/
               
                input_sync(button_dev);
                break;
            }   
        }
        /*返回值*/
       
        return IRQ_RETVAL(IRQ_HANDLED);
    }

    /*设备初始化函数*/

    static int __init tq2440_button_init(void)
    {
        int err,i = 0;
        /*主要要先申请设备，然后申请中断*/
       
        /*申请输入设备*/
        button_dev = input_allocate_device();
       
        if(NULL == button_dev)
        {
            printk(KERN_ERR "not enough memory\n");
            err = - ENOMEM;
        }
       
        /*设置相应的事件处理类型,按键事件*/
        set_bit(EV_KEY,button_dev->evbit);

        /*申请中断*/
        for(i = 0; i < NUMBERS_BUTTONS; ++ i)
        {
            /*申请中断*/
            request_irq(irqs[i],button_interrupt,IRQ_TYPE_EDGE_BOTH,
                DEVICE_NAME,NULL);
            /*设置案件的代码值,即code值*/
            set_bit(keys[i],button_dev->keybit);
        }
           
        /*设备名，防止出现错误*/
        button_dev->name = input_name;   
       
        /*注册输入设备*/
        err = input_register_device(button_dev);
       
        if(err)
        {
            printk(KERN_ERR "failed to register device\n");
           
            goto err_free_dev;
        }
       
        printk("initialized\n");

        return 0;

    /*错误处理*/
    err_free_dev:
        /*注销设备*/
        input_unregister_device(button_dev);
        return err;
    }

    /*设备退出函数*/
    static void __exit tq2440_button_exit(void)
    {
        int i = 0;
        input_unregister_device(button_dev);

        /*释放中断号*/
        for(i = 0; i < NUMBERS_BUTTONS; ++ i)
        {
            free_irq(irqs[i],NULL);
        }
    }

    /*加载和卸载*/
    module_init(tq2440_button_init);
    module_exit(tq2440_button_exit);

    /*LICENSE和作者信息*/
    MODULE_LICENSE("GPL");
    MODULE_AUTHOR("GP-<gp19861112@yahoo.com.cn>");

测试代码：

    #include<stdio.h>
    #include<stdlib.h>
    #include<sys/types.h>
    #include<sys/stat.h>
    #include<fcntl.h>
    #include<unistd.h>
    #include<linux/input.h>

    /*事件结构体*/
    struct input_event buff;

    int main(int argc ,char **argv)
    {
        int fd;
        int count;
        /*打开设备文件*/
        fd = open("/dev/event0",O_RDWR);

        if(fd == -1)
        {
            printf("Open Failed!\n");

            exit(-1);
        }

        while(1)
        {
            /*读操作*/
            if(count = read(fd,&buff,sizeof(struct input_event))!=0)
            {
                printf("type: %d\tcode: %d\t value: %d\n",buff.type,buff.code,buff.value);
            }
        }
       
        close(fd);
        exit(0);
    }

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