This driver's ->rs485_config callback checks if SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND have the same value. If they do, it means the user has passed in invalid data with the TIOCSRS485 ioctl() since RTS must have a different polarity when sending and when not sending. In this case, rs485 mode is not enabled (the RS485_URA bit is not set in the RS485 Enable Register) and this is supposed to be signaled back to the user by clearing the SER_RS485_ENABLED bit in struct serial_rs485 ... except a missing tilde character is preventing that from happening. Fixes: 28e3fb6c4dce ("serial: Add support for Fintek F81216A LPC to 4 UART") Cc: Ricardo Ribalda Delgado <ricardo.ribalda@xxxxxxxxx> Cc: "Ji-Ze Hong (Peter Hong)" <hpeter@xxxxxxxxx> Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx> --- Changes v1 -> v2: - Tone down commit message by changing "nonsensical" to "invalid". (Ricardo) drivers/tty/serial/8250/8250_fintek.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c index b346239..c41cbb5 100644 --- a/drivers/tty/serial/8250/8250_fintek.c +++ b/drivers/tty/serial/8250/8250_fintek.c @@ -221,7 +221,7 @@ static int fintek_8250_rs485_config(struct uart_port *port, if ((!!(rs485->flags & SER_RS485_RTS_ON_SEND)) == (!!(rs485->flags & SER_RS485_RTS_AFTER_SEND))) - rs485->flags &= SER_RS485_ENABLED; + rs485->flags &= ~SER_RS485_ENABLED; else config |= RS485_URA; -- 2.11.0 -- To unsubscribe from this list: send the line "unsubscribe linux-serial" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html