+ Initialize the serial device hardware.\r
+ \r
+ If no initialization is required, then return RETURN_SUCCESS.\r
+ If the serial device was successfully initialized, then return RETURN_SUCCESS.\r
+ If the serial device could not be initialized, then return RETURN_DEVICE_ERROR.\r
+ \r
+ @retval RETURN_SUCCESS The serial device was initialized.\r
+ @retval RETURN_DEVICE_ERROR The serial device could not be initialized.\r