UART_FCR_R_TRIG_00
UART_FCR_R_TRIG_00 | UART_FCR_T_TRIG_00,
.fcr = UART_FCR_ENABLE_FIFO | UART_FCR_R_TRIG_00,
if (!conf_type->rxtrig_bytes[UART_FCR_R_TRIG_BITS(UART_FCR_R_TRIG_00)])