6.6-stable review patch. If anyone has any objections, please let me know.
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From: Lino Sanfilippo l.sanfilippo@kunbus.com
commit 74eab89b26ac433ad857292f4707b43c1a8f0209 upstream.
If the imx driver cannot support RS485 it nullifies the ports rs485_supported structure. 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. So remove this check.
Furthermore the explicit nullifcation of rs485_supported is not needed, since the memory has already been set to zeros at allocation. So remove this, 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 Reviewed-by: Ilpo Järvinen ilpo.jarvinen@linux.intel.com Link: https://lore.kernel.org/r/20240103061818.564-6-l.sanfilippo@kunbus.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/tty/serial/imx.c | 7 ------- drivers/tty/serial/serial_core.c | 3 +++ 2 files changed, 3 insertions(+), 7 deletions(-)
--- a/drivers/tty/serial/imx.c +++ b/drivers/tty/serial/imx.c @@ -2214,7 +2214,6 @@ static enum hrtimer_restart imx_trigger_ return HRTIMER_NORESTART; }
-static const struct serial_rs485 imx_no_rs485 = {}; /* No RS485 if no RTS */ static const struct serial_rs485 imx_rs485_supported = { .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX, @@ -2298,8 +2297,6 @@ static int imx_uart_probe(struct platfor /* RTS is required to control the RS485 transmitter */ if (sport->have_rtscts || sport->have_rtsgpio) sport->port.rs485_supported = imx_rs485_supported; - else - sport->port.rs485_supported = imx_no_rs485; sport->port.flags = UPF_BOOT_AUTOCONF; timer_setup(&sport->timer, imx_uart_timeout, 0);
@@ -2336,10 +2333,6 @@ static int imx_uart_probe(struct platfor 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 --- a/drivers/tty/serial/serial_core.c +++ b/drivers/tty/serial/serial_core.c @@ -3576,6 +3576,9 @@ int uart_get_rs485_mode(struct uart_port int ret; int rx_during_tx_gpio_flag;
+ 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) {