字符設備驅動程序按鍵驅動---中斷方式

時間  2019-12-12
標籤 字符 設備 驅動程序 按鍵 驅動 中斷 方式 简体版
原文   原文鏈接

中斷函數：包含#include<linux/irq.h>node

request_irq(irq,handle,irqflag,name,dev_id)linux

{函數

    1,分配一個irqaction結構體this

    二、把這個結構體放到irq_desc[irq]（action鏈表）中spa

   三、設置引腳code

   四、使能中斷blog

}進程

free_irq(irq,dev_id)事件

{ci

      一、irqaciton出鏈

      二、禁止中斷

}

---------------------------------------------------------------------------------------------------------------------------------------

一、open函數裏，配置中斷引腳，中斷方式irqflags,中斷號irq(如外部中斷,用於代表哪一個引腳)，處理函數handle，中斷名name,設備號dev_id

    調用request_irq(irq,handle,irqflag,name,dev_id)

static int third_drv_open(struct inode *inode, struct file *file)
{
/* 配置GPF0,2爲輸入引腳 */
/* 配置GPG3,11爲輸入引腳 */
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;
}

 

二、在file_operation結構體添加

.release = third_drv_close,
用於關閉中斷函數

int third_drv_close(struct inode *inode, struct file *file)
{
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]);
return 0;
}

--------------------------------------------------------------------------------------------------------------------------------------------------

中斷處理函數Button_irq對中斷髮生時須要處理的事件，本次主要時對按鍵中斷函數處理

/* 鍵值: 按下時, 0x01, 0x02, 0x03, 0x04 */
/* 鍵值: 鬆開時, 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},
};

 

/*
* 肯定按鍵值
*/
static irqreturn_t buttons_irq(int irq, void *dev_id)
{

/* 引腳描述結構體 */
struct pin_desc * pindesc = (struct pin_desc *)dev_id;
unsigned int pinval;

/* 系統函數讀出引腳值 */
pinval = s3c2410_gpio_getpin(pindesc->pin);

if (pinval)
{
/* 鬆開 */
key_val = 0x80 | pindesc->key_val;
}
else
{
/* 按下 */
key_val = pindesc->key_val;
}

ev_press = 1; /* 表示中斷髮生了 */
wake_up_interruptible(&button_waitq); /* 喚醒休眠的進程 */


return IRQ_RETVAL(IRQ_HANDLED);
}

----------------------------------------------------------------------------------------------------------------------------------------------------

讀函數須要處理的事件

一、判斷按鍵發生事件 ，沒有就休眠，讓出CPU

二、有按鍵事件發生，返回按鍵值

/* 中斷事件標誌, 中斷服務程序將它置1，third_drv_read將它清0 */
static volatile int ev_press = 0;


struct pin_desc{
unsigned int pin;
unsigned int key_val;
};

 

ssize_t third_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
if (size != 1)
return -EINVAL;

/* 若是沒有按鍵動做, 休眠 */
wait_event_interruptible(button_waitq, ev_press);

/* 若是有按鍵動做, 返回鍵值 */
copy_to_user(buf, &key_val, 1);
ev_press = 0;

return 1;
}

------------------------------------------------------------------------------------------------------------------------------------------

相關按鍵中斷驅動代碼：

third_drv.c

#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>


static struct class *thirddrv_class;
static struct class_device    *thirddrv_class_dev;

volatile unsigned long *gpfcon;
volatile unsigned long *gpfdat;

volatile unsigned long *gpgcon;
volatile unsigned long *gpgdat;


static DECLARE_WAIT_QUEUE_HEAD(button_waitq);

/* 中斷事件標誌, 中斷服務程序將它置1，third_drv_read將它清0 */
static volatile int ev_press = 0;


struct pin_desc{
    unsigned int pin;
    unsigned int key_val;
};


/* 鍵值: 按下時, 0x01, 0x02, 0x03, 0x04 */
/* 鍵值: 鬆開時, 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},
};


/*
  * 肯定按鍵值
  */
static irqreturn_t buttons_irq(int irq, void *dev_id)
{
    struct pin_desc * pindesc = (struct pin_desc *)dev_id;
    unsigned int pinval;
    
    pinval = s3c2410_gpio_getpin(pindesc->pin);

    if (pinval)
    {
        /* 鬆開 */
        key_val = 0x80 | pindesc->key_val;
    }
    else
    {
        /* 按下 */
        key_val = pindesc->key_val;
    }

    ev_press = 1;                  /* 表示中斷髮生了 */
    wake_up_interruptible(&button_waitq);   /* 喚醒休眠的進程 */

    
    return IRQ_RETVAL(IRQ_HANDLED);
}

static int third_drv_open(struct inode *inode, struct file *file)
{
    /* 配置GPF0,2爲輸入引腳 */
    /* 配置GPG3,11爲輸入引腳 */
    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 third_drv_read(struct file *file, char __user *buf, size_t size, loff_t *ppos)
{
    if (size != 1)
        return -EINVAL;

    /* 若是沒有按鍵動做, 休眠 */
    wait_event_interruptible(button_waitq, ev_press);

    /* 若是有按鍵動做, 返回鍵值 */
    copy_to_user(buf, &key_val, 1);
    ev_press = 0;
    
    return 1;
}


int third_drv_close(struct inode *inode, struct file *file)
{
    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]);
    return 0;
}


static struct file_operations sencod_drv_fops = {
    .owner   =  THIS_MODULE,    /* 這是一個宏，推向編譯模塊時自動建立的__this_module變量 */
    .open    =  third_drv_open,     
    .read     =    third_drv_read,       
    .release =  third_drv_close,       
};


int major;
static int third_drv_init(void)
{
    major = register_chrdev(0, "third_drv", &sencod_drv_fops);

    thirddrv_class = class_create(THIS_MODULE, "third_drv");

    thirddrv_class_dev = class_device_create(thirddrv_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 third_drv_exit(void)
{
    unregister_chrdev(major, "third_drv");
    class_device_unregister(thirddrv_class_dev);
    class_destroy(thirddrv_class);
    iounmap(gpfcon);
    iounmap(gpgcon);
    return 0;
}


module_init(third_drv_init);

module_exit(third_drv_exit);

MODULE_LICENSE("GPL");

 

Makefile

KERN_DIR = /work/system/linux-2.6.22.6

all:
    make -C $(KERN_DIR) M=`pwd` modules 

clean:
    make -C $(KERN_DIR) M=`pwd` modules clean
    rm -rf modules.order

obj-m    += third_drv.o

thirddrvtest.c

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>

/* thirddrvtest 
  */
int main(int argc, char **argv)
{
    int fd;
    unsigned char key_val;
    
    fd = open("/dev/buttons", O_RDWR);
    if (fd < 0)
    {
        printf("can't open!\n");
    }

    while (1)
    {
        read(fd, &key_val, 1);
        printf("key_val = 0x%x\n", key_val);
    }
    
    return 0;
}
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