1 alloc_chrdev_region(); /* 申请设备号 */
2 cdev_init(); /* 初始化 cdev */
3 cdev_add(); /* 添加 cdev */
4 class_create(); /* 创建类 */
5 device_create(); /* 创建设备 */

1 cdev_del(); /* 删除 cdev */
2 unregister_chrdev_region(); /* 注销设备号 */
3 device_destroy(); /* 删除设备 */
4 class_destroy(); /* 删除类 */

驱动示例如下所示：

#define MISCBEEP_NAME "miscbeep"
#define MISCBEEP_MINOR 144
#define BEEPOFF 0
#define BEEPON 1/* miscbeep设备结构体 */
struct miscbeep_dev
{struct device_node *nd; /* 设备节点 */int beep_gpio;          /* beep gpio */
};struct miscbeep_dev miscbeep;static int miscbeep_open(struct inode *inode, struct file *filp)
{filp->private_data = &miscbeep;return 0;
}static int miscbeep_release(struct inode *inode, struct file *filp)
{return 0;
}static ssize_t miscbeep_write(struct file *filp, const char __user *buf,size_t count, loff_t *ppos)
{int ret;unsigned char databuf[1];struct miscbeep_dev *dev = filp->private_data;return 0;
}/* 设备操作函数 */
struct file_operations miscbeep_fops = {.owner = THIS_MODULE,.open = miscbeep_open,.release = miscbeep_release,.write = miscbeep_write,
};/* miscdevice结构体 */
static struct miscdevice beep_miscdev = {.minor = MISCBEEP_MINOR,.name = MISCBEEP_NAME,.fops = &miscbeep_fops,
};/* probe函数 */
static int miscbeep_probe(struct platform_device *dev)
{int ret = 0;/* 1、初始化锋鸣器IO */miscbeep.nd = dev->dev.of_node;miscbeep.beep_gpio = of_get_named_gpio(miscbeep.nd, "beep-gpios", 0);if (miscbeep.beep_gpio < 0){}ret = gpio_request(miscbeep.beep_gpio, "beep-gpio");if (ret){}ret = gpio_direction_output(miscbeep.beep_gpio, 1); /* 输出，默认高电平 */if (ret < 0){}/* 2、misc驱动注册，无需进行字符驱动注册那一系列步骤 */ret = misc_register(&beep_miscdev);if (ret < 0){goto fail_setoutput;}return 0;}/* remove函数 */
static int miscbeep_remove(struct platform_device *dev)
{gpio_set_value(miscbeep.beep_gpio, 1); /* 拉高，关闭BEEP */gpio_free(miscbeep.beep_gpio);         /* 释放GPIO *//* 2、misc驱动注销，无需进行字符驱动注销那一系列步骤 */misc_deregister(&beep_miscdev);return 0;
}/* platform匹配表 */
static const struct of_device_id beep_of_match[] = {{.compatible = "alientek,beep"},{/* Sentinel */},
};/* platform */
static struct platform_driver miscbeep_driver = {.driver = {.name = "imx6ul-beep",.of_match_table = beep_of_match, /* 设备树匹配表 */},.probe = miscbeep_probe,.remove = miscbeep_remove,
};/* 驱动入口函数 */
static int __init miscbeep_init(void)
{return platform_driver_register(&miscbeep_driver);
}/* 驱动出口函数 */
static void __exit miscbeep_exit(void)
{platform_driver_unregister(&miscbeep_driver);
}module_init(miscbeep_init);
module_exit(miscbeep_exit);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("supersmart");