serial: stm32: do not always set SER_RS485_RX_DURING_TX if RS485 is enabled

Before commit 07c30ea5861f ("serial: Do not hold the port lock when setting
rx-during-tx GPIO") the SER_RS485_RX_DURING_TX flag was only set if the
rx-during-tx mode was not controlled by a GPIO. Now the flag is set
unconditionally when RS485 is enabled. This results in an incorrect setting
if the rx-during-tx GPIO is not asserted.

Fix this by setting the flag only if the rx-during-tx mode is not
controlled by a GPIO and thus restore the correct behaviour.

Cc: stable@vger.kernel.org # 6.6+
Fixes: 07c30ea5861f ("serial: Do not hold the port lock when setting rx-during-tx GPIO")
Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com>
Link: https://lore.kernel.org/r/20240216224709.9928-1-l.sanfilippo@kunbus.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/serial/stm32-usart.c b/drivers/tty/serial/stm32-usart.c
index 794b7751274034848c65a7e3374b694bcf61c42d..693e932d6feb5842467d1408e04c8d574342cb1f 100644 (file)
--- a/drivers/tty/serial/stm32-usart.c
+++ b/drivers/tty/serial/stm32-usart.c
@@ -251,7 +251,9 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter
                writel_relaxed(cr3, port->membase + ofs->cr3);
                writel_relaxed(cr1, port->membase + ofs->cr1);
 
-               rs485conf->flags |= SER_RS485_RX_DURING_TX;
+               if (!port->rs485_rx_during_tx_gpio)
+                       rs485conf->flags |= SER_RS485_RX_DURING_TX;
+
        } else {
                stm32_usart_clr_bits(port, ofs->cr3,
                                     USART_CR3_DEM | USART_CR3_DEP);