| From foo@baz Wed Dec 6 18:04:41 CET 2017 |
| From: Lukas Wunner <lukas@wunner.de> |
| Date: Sat, 28 Oct 2017 11:35:49 +0200 |
| Subject: serial: 8250_fintek: Fix rs485 disablement on invalid ioctl() |
| |
| From: Lukas Wunner <lukas@wunner.de> |
| |
| |
| [ 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> |
| --- |
| drivers/tty/serial/8250/8250_fintek.c | 2 +- |
| 1 file changed, 1 insertion(+), 1 deletion(-) |
| |
| --- 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(stru |
| |
| 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; |
| |
