基类对象，定义在rtdef.h中

struct rt_object
{char name[RT_NAME_MAX];rt_uint8_t type; //设备类Devicert_uint8_t flag;rt_list_t list;
}; //同一类对象挂接在一个链表上

设备基类，定义在rtdef.h中（属于设备接口层）

struct rt_device
{struct rt_object parent;enum rt_device_class_type type;rt_uint16_t flag;rt_uint16_t open_flag;rt_uint8_t                ref_count;                /**< reference count */rt_uint8_t                device_id;                /**< 0 - 255 *//* device call back */rt_err_t (*rx_indicate)(rt_device_t dev, rt_size_t size);rt_err_t (*tx_complete)(rt_device_t dev, void *buffer);/* common device interface */rt_err_t  (*init)   (rt_device_t dev);rt_err_t  (*open)   (rt_device_t dev, rt_uint16_t oflag);rt_err_t  (*close)  (rt_device_t dev);rt_ssize_t (*read)  (rt_device_t dev, rt_off_t pos, void *buffer, rt_size_t size);rt_ssize_t (*write) (rt_device_t dev, rt_off_t pos, const void *buffer, rt_size_t size);rt_err_t  (*control)(rt_device_t dev, int cmd, void *args);void                     *user_data;                /**< device private data */
}

在pin.h中（属于设备驱动框架层）

struct rt_device_pin
{struct rt_device parent;const struct rt_pin_ops *ops;
};

struct rt_pin_ops
{void (*pin_mode)(struct rt_device *device, rt_base_t pin, rt_uint8_t mode);void (*pin_write)(struct rt_device *device, rt_base_t pin, rt_uint8_t value);rt_int8_t  (*pin_read)(struct rt_device *device, rt_base_t pin);rt_err_t (*pin_attach_irq)(struct rt_device *device, rt_base_t pin,rt_uint8_t mode, void (*hdr)(void *args), void *args);rt_err_t (*pin_detach_irq)(struct rt_device *device, rt_base_t pin);rt_err_t (*pin_irq_enable)(struct rt_device *device, rt_base_t pin, rt_uint8_t enabled);rt_base_t (*pin_get)(const char *name);
};

在drv_gpio.c中（属于设备驱动层）
实现了设备驱动框架层的操作接口

static const struct rt_pin_ops _stm32_pin_ops = 
{stm32_pin_mode,stm32_pin_write,stm32_pin_read,stm32_pin_attach_irq,stm32_pin_dettach_irq,stm32_pin_irq_enable,stm32_pin_get,
};

直接注册

rt_hw_pin_init(void)
{return rt_device_pin_register("pin", &_stm32_pin_ops, RT_NULL);
}

设备驱动框架层pin.c中定义了
static struct rt_device_pin _hw_pin;

struct rt_device_pin_value
{rt_base_t pin;rt_uint8_t value;
}

int rt_device_pin_register(const char*name, const struct rt_pin_ops *ops, void *user_data)
{_hw_pin.parent.type = RT_Device_Class_Pin;_hw_pin.parent.rx_indicate = RT_NULL;_hw_pin.parent.tx_complete = RT_NULL;_hw_pin.parent.init         = RT_NULL;_hw_pin.parent.open         = RT_NULL;_hw_pin.parent.close        = RT_NULL;_hw_pin.parent.read 		= _pin_read;_hw_pin.parent.write        = _pin_write;_hw_pin.parent.control      = _pin_control;_hw_pin.ops					= ops;_hw_pin.parent.user_data	= user_data;rt_device_register(&_hw_pin.parent, name, RT_DEVICE_FLAG_RDWR);return 0;
}