1.设备驱动模块加载函数:module_init()

static int Module_init(void)
{
    int result;
    /*将主设备号和次设备号转换成dev_t类型*/
    dev_t devno = MKDEV(major, 0);
    /* 申请设备号*/
    if (major)
    {
        /*静态*/
         result = register_chrdev_region(devno, 2, "devname");
    }
    else
    {/*动态*/
        result = alloc_chrdev_region(&devno, 0, 2, "devname");
        usercdev_major = MAJOR(devno);
    }
    if (result < 0)
    {
        return result;
    }
    /*初始化cdev结构*/
    cdev_init(&cdev, &file_fops);
    cdev.owner = THIS_MODULE;
    cdev.ops = &file_fops;
    /* 注册字符设备 */
    cdev_add(&cdev, MKDEV(major, 0), DEVNR);
    /* 为设备描述结构分配内存*/
    pDevDescst = kmalloc(USERCDEV_NR_DEVS * sizeof(struct  usercdev_dev), GFP_KERNEL);
    if (!pDevDescst) /*申请失败*/
    {
        result = - ENOMEM;
        unregister_chrdev_region(devno, 1); /*申请失败处理*/
        return result;
    }
    else
    {
         memset(pDevDescst, 0, sizeof(struct  DevDescs));
        /*为设备分配内存*/
        for (i=0; i < DEVS_NR; i++)
        {
            pDevDescst[i].size = DEV_SIZE;
            pDevDescst[i].data = kmalloc(DEV_SIZE, GFP_KERNEL);
            memset(pDevDescst[i].data, 0,DEV_SIZE);
        }
    }
}

2.模块卸载函数  Module_exit()

static void Module_exit(void)
{
     /*注销设备*/
     cdev_del(&cdev);
     /*释放设备结构体内存*/  
     kfree(pDevDescst);
     /*释放设备号*/
     unregister_chrdev_region(MKDEV(major, 0), 2);
}

linux 学习笔记--模块的加载与卸载