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authorIlpo Järvinen <ilpo.jarvinen@linux.intel.com>2022-05-13 16:46:43 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2022-05-19 18:31:12 +0200
commitaf0179270977508df6986b51242825d7edd59caf (patch)
tree5028fc24741d51b6d77d344b42dea560a6e8dd54 /drivers/tty
parentf0136f65285bcfb7e8f90d1013723076a35acd51 (diff)
downloadlinux-af0179270977508df6986b51242825d7edd59caf.tar.bz2
serial: 8250_fintek: Check SER_RS485_RTS_* only with RS485
SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND relate to behavior within RS485 operation. The driver checks if they have the same value which is not possible to realize with the hardware. The check is taken regardless of SER_RS485_ENABLED flag and -EINVAL is returned when the check fails, which creates problems. This check makes it unnecessarily complicated to turn RS485 mode off as simple zeroed serial_rs485 struct will trigger that equal values check. In addition, the driver itself memsets its rs485 structure to zero when RS485 is disabled but if userspace would try to make an TIOCSRS485 ioctl() call with the very same struct, it would end up failing with -EINVAL which doesn't make much sense. Resolve the problem by moving the check inside SER_RS485_ENABLED block. Fixes: 7ecc77011c6f ("serial: 8250_fintek: Return -EINVAL on invalid configuration") Cc: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com> Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Link: https://lore.kernel.org/r/035c738-8ea5-8b17-b1d7-84a7b3aeaa51@linux.intel.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serial/8250/8250_fintek.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c
index 251f0018ae8c..dba5950b8d0e 100644
--- a/drivers/tty/serial/8250/8250_fintek.c
+++ b/drivers/tty/serial/8250/8250_fintek.c
@@ -200,12 +200,12 @@ static int fintek_8250_rs485_config(struct uart_port *port,
if (!pdata)
return -EINVAL;
- /* Hardware do not support same RTS level on send and receive */
- if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
- !(rs485->flags & SER_RS485_RTS_AFTER_SEND))
- return -EINVAL;
if (rs485->flags & SER_RS485_ENABLED) {
+ /* Hardware do not support same RTS level on send and receive */
+ if (!(rs485->flags & SER_RS485_RTS_ON_SEND) ==
+ !(rs485->flags & SER_RS485_RTS_AFTER_SEND))
+ return -EINVAL;
memset(rs485->padding, 0, sizeof(rs485->padding));
config |= RS485_URA;
} else {