@@ -1943,10 +1943,6 @@ static int imx_uart_rs485_config(struct uart_port *port, struct ktermios *termio
rs485conf->flags & SER_RS485_RX_DURING_TX)
imx_uart_start_rx(port);
- if (port->rs485_rx_during_tx_gpio)
- gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
- !!(rs485conf->flags & SER_RS485_RX_DURING_TX));
-
return 0;
}
@@ -1402,6 +1402,16 @@ static void uart_set_rs485_termination(struct uart_port *port,
!!(rs485->flags & SER_RS485_TERMINATE_BUS));
}
+static void uart_set_rs485_rx_during_tx(struct uart_port *port,
+ const struct serial_rs485 *rs485)
+{
+ if (!(rs485->flags & SER_RS485_ENABLED))
+ return;
+
+ gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
+ !!(rs485->flags & SER_RS485_RX_DURING_TX));
+}
+
static int uart_rs485_config(struct uart_port *port)
{
struct serial_rs485 *rs485 = &port->rs485;
@@ -1413,12 +1423,17 @@ static int uart_rs485_config(struct uart_port *port)
uart_sanitize_serial_rs485(port, rs485);
uart_set_rs485_termination(port, rs485);
+ uart_set_rs485_rx_during_tx(port, rs485);
uart_port_lock_irqsave(port, &flags);
ret = port->rs485_config(port, NULL, rs485);
uart_port_unlock_irqrestore(port, flags);
- if (ret)
+ if (ret) {
memset(rs485, 0, sizeof(*rs485));
+ /* unset GPIOs */
+ gpiod_set_value_cansleep(port->rs485_term_gpio, 0);
+ gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio, 0);
+ }
return ret;
}
@@ -1457,6 +1472,7 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
return ret;
uart_sanitize_serial_rs485(port, &rs485);
uart_set_rs485_termination(port, &rs485);
+ uart_set_rs485_rx_during_tx(port, &rs485);
uart_port_lock_irqsave(port, &flags);
ret = port->rs485_config(port, &tty->termios, &rs485);
@@ -1468,8 +1484,14 @@ static int uart_set_rs485_config(struct tty_struct *tty, struct uart_port *port,
port->ops->set_mctrl(port, port->mctrl);
}
uart_port_unlock_irqrestore(port, flags);
- if (ret)
+ if (ret) {
+ /* restore old GPIO settings */
+ gpiod_set_value_cansleep(port->rs485_term_gpio,
+ !!(port->rs485.flags & SER_RS485_TERMINATE_BUS));
+ gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
+ !!(port->rs485.flags & SER_RS485_RX_DURING_TX));
return ret;
+ }
if (copy_to_user(rs485_user, &port->rs485, sizeof(port->rs485)))
return -EFAULT;
@@ -226,10 +226,7 @@ static int stm32_usart_config_rs485(struct uart_port *port, struct ktermios *ter
stm32_usart_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
- if (port->rs485_rx_during_tx_gpio)
- gpiod_set_value_cansleep(port->rs485_rx_during_tx_gpio,
- !!(rs485conf->flags & SER_RS485_RX_DURING_TX));
- else
+ if (!port->rs485_rx_during_tx_gpio)
rs485conf->flags |= SER_RS485_RX_DURING_TX;
if (rs485conf->flags & SER_RS485_ENABLED) {
Both the imx and stm32 driver set the rx-during-tx GPIO in rs485_config(). Since this function is called with the port lock held, this can be an problem in case that setting the GPIO line can sleep (e.g. if a GPIO expander is used which is connected via SPI or I2C). Avoid this issue by moving the GPIO setting outside of the port lock into the serial core and thus making it a generic feature. Also reset old GPIO settings in case that changing the RS485 configuration failed. Fixes: c54d48543689 ("serial: stm32: Add support for rs485 RX_DURING_TX output GPIO") Fixes: ca530cfa968c ("serial: imx: Add support for RS485 RX_DURING_TX output GPIO") Cc: Shawn Guo <shawnguo@kernel.org> Cc: Sascha Hauer <s.hauer@pengutronix.de> Cc: stable@vger.kernel.org Signed-off-by: Lino Sanfilippo <l.sanfilippo@kunbus.com> --- drivers/tty/serial/imx.c | 4 ---- drivers/tty/serial/serial_core.c | 26 ++++++++++++++++++++++++-- drivers/tty/serial/stm32-usart.c | 5 +---- 3 files changed, 25 insertions(+), 10 deletions(-)