If the imx driver cannot support RS485 it sets the ports rs485_supported structure to NULL. But it still calls uart_get_rs485_mode() which may set the RS485_ENABLED flag nevertheless.

This may lead to an attempt to configure RS485 even if it is not supported when the flag is evaluated in uart_configure_port() at port startup.

Avoid this by bailing out of uart_get_rs485_mode() if the RS485_ENABLED flag is not supported by the caller.

With this fix a check for RTS availability is now obsolete in the imx driver, since it can not evaluate to true any more. Remove this check, too.

Fixes: 00d7a00e2a6f ("serial: imx: Fill in rs485_supported") Cc: Shawn Guo shawnguo@kernel.org Cc: Sascha Hauer s.hauer@pengutronix.de Cc: stable@vger.kernel.org Suggested-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Signed-off-by: Lino Sanfilippo l.sanfilippo@kunbus.com --- drivers/tty/serial/imx.c | 4 ---- drivers/tty/serial/serial_core.c | 3 +++ 2 files changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c index 9cffeb23112b..98b78d360a74 100644 --- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2328,10 +2328,6 @@ static int imx_uart_probe(struct platform_device *pdev) return ret; }

- if (sport->port.rs485.flags & SER_RS485_ENABLED && - (!sport->have_rtscts && !sport->have_rtsgpio)) - dev_err(&pdev->dev, "no RTS control, disabling rs485\n"); - /* * If using the i.MX UART RTS/CTS control then the RTS (CTS_B) * signal cannot be set low during transmission in case the diff --git a/drivers/tty/serial/serial_core.c b/drivers/tty/serial/serial_core.c index b636e2ce6e8b..518e19036983 100644 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -3588,6 +3588,9 @@ int uart_get_rs485_mode(struct uart_port *port) u32 rs485_delay[2]; int ret;

+ if (!(port->rs485_supported.flags & SER_RS485_ENABLED)) + return 0; + ret = device_property_read_u32_array(dev, "rs485-rts-delay", rs485_delay, 2); if (!ret) {