6.7-stable review patch. If anyone has any objections, please let me know.
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From: Lino Sanfilippo l.sanfilippo@kunbus.com
commit 07c30ea5861fb26a77dade8cdc787252f6122fb1 upstream.
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 a 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 with commit c54d48543689 ("serial: stm32: Add support for rs485 RX_DURING_TX output GPIO") the SER_RS485_RX_DURING_TX flag is only set if a rx-during-tx GPIO is _not_ available, which is wrong. Fix this, too.
Furthermore 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 Link: https://lore.kernel.org/r/20240103061818.564-2-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/imx.c | 4 ---- drivers/tty/serial/serial_core.c | 26 ++++++++++++++++++++++++-- drivers/tty/serial/stm32-usart.c | 8 ++------ 3 files changed, 26 insertions(+), 12 deletions(-)
--- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -1943,10 +1943,6 @@ static int imx_uart_rs485_config(struct 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; }
--- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -1402,6 +1402,16 @@ static void uart_set_rs485_termination(s !!(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
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 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 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; --- a/drivers/tty/serial/stm32-usart.c +++ b/drivers/tty/serial/stm32-usart.c @@ -226,12 +226,6 @@ static int stm32_usart_config_rs485(stru
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 - rs485conf->flags |= SER_RS485_RX_DURING_TX; - if (rs485conf->flags & SER_RS485_ENABLED) { cr1 = readl_relaxed(port->membase + ofs->cr1); cr3 = readl_relaxed(port->membase + ofs->cr3); @@ -256,6 +250,8 @@ static int stm32_usart_config_rs485(stru
writel_relaxed(cr3, port->membase + ofs->cr3); writel_relaxed(cr1, port->membase + ofs->cr1); + + rs485conf->flags |= SER_RS485_RX_DURING_TX; } else { stm32_usart_clr_bits(port, ofs->cr3, USART_CR3_DEM | USART_CR3_DEP);