From: Lukas Wunner <lukas@wunner.de>
Date: Sat, 28 Oct 2017 09:35:49 +0000 (+0200)
Subject: serial: 8250_fintek: Fix rs485 disablement on invalid ioctl()
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4bee9d1d1c54c8bf9ff8149ccacbaf398f524a37;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

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


[ Upstream commit 3236a965486ba0c6043cf2c7b51943d8b382ae29 ]

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@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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index 4bd376c08b59..ba4af5434b91 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -211,7 +211,7 @@ 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;