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@xxxxxxxxxx>
Cc: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Suggested-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Signed-off-by: Lino Sanfilippo <l.sanfilippo@xxxxxxxxxx>
---
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) {
--
2.42.0
