linux系统上，SPI UART协议驱动程序，欢迎使用。-linux system, SPI UART protocol driver, welcome to use.

i2c或者spi 转uart 芯片的驱动代码，外国的芯片，原厂的代码，采用regmap 的注册方式，学习和参考的绝佳资料-i2c or spi to uart driver code， it is aboard， it is good for study and referce！

note: 1.please follow the user guide:SIMCom_SIM800H_EAT_RVCT_Installation_User Manual_V1.01.pdf which is in foler environment_RVCT to install the environment of sim800H EAT. 2.please install the usb driver before you upgrading the firmware. 3.s