IIC核心函数与“万能”驱动
IIC核心函数与“万能”驱动i2c_add_adapter()函数drivers/i2c/i2c-core-base.c注册一个i2c适配器int i2c_add_adapter(struct i2c_adapter *adapter)int i2c_add_numbered_adapter(struct i2c_adapter *adapter)adapter->nr：适配器的编号参数：adapter：i2c物理控制器对应的适配器返回值：成功：0失败：负数i2c_a
