This is a note to let you know that I've just added the patch titled

serial: 8250_exar: Set missing rs485_supported flag

to my tty git tree which can be found at git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty.git in the tty-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the tty-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From 0c2a5f471ce58bca8f8ab5fcb911aff91eaaa5eb Mon Sep 17 00:00:00 2001 From: Lino Sanfilippo l.sanfilippo@kunbus.com Date: Wed, 3 Jan 2024 07:18:18 +0100 Subject: serial: 8250_exar: Set missing rs485_supported flag MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit

The UART supports an auto-RTS mode in which the RTS pin is automatically activated during transmission. So mark this mode as being supported even if RTS is not controlled by the driver but the UART.

Also the serial core expects now at least one of both modes rts-on-send or rts-after-send to be supported. This is since during sanitization unsupported flags are deleted from a RS485 configuration set by userspace. However if the configuration ends up with both flags unset, the core prints a warning since it considers such a configuration invalid (see uart_sanitize_serial_rs485()).

Cc: stable@vger.kernel.org Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Signed-off-by: Lino Sanfilippo l.sanfilippo@kunbus.com Link: https://lore.kernel.org/r/20240103061818.564-8-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/8250/8250_exar.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_exar.c b/drivers/tty/serial/8250/8250_exar.c index 6085d356ad86..23366f868ae3 100644 --- a/drivers/tty/serial/8250/8250_exar.c +++ b/drivers/tty/serial/8250/8250_exar.c @@ -480,7 +480,7 @@ static int sealevel_rs485_config(struct uart_port *port, struct ktermios *termio }

static const struct serial_rs485 generic_rs485_supported = { - .flags = SER_RS485_ENABLED, + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND, };

static const struct exar8250_platform exar8250_default_platform = { @@ -524,7 +524,8 @@ static int iot2040_rs485_config(struct uart_port *port, struct ktermios *termios }

static const struct serial_rs485 iot2040_rs485_supported = { - .flags = SER_RS485_ENABLED | SER_RS485_RX_DURING_TX | SER_RS485_TERMINATE_BUS, + .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | + SER_RS485_RX_DURING_TX | SER_RS485_TERMINATE_BUS, };

static const struct property_entry iot2040_gpio_properties[] = {