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serial: 8250_fintek: Fix rs485 disablement on invalid ioctl() 

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: 28e3fb6c4d ("serial: Add support for Fintek F81216A LPC to 4 UART")
Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
Cc: "Ji-Ze Hong (Peter Hong)" <hpeter@gmail.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lukas Wunner 2017-10-28 11:35:49 +02:00 committed by Greg Kroah-Hartman
parent 9356335faf
commit 3236a96548
1 changed files with 1 additions and 1 deletions
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2
drivers/tty/serial/8250/8250_fintek.c
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@ -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;