From: Mathieu Othacehe <othacehe@xxxxxxx>
commit c9f6613b16123989f2c3bd04b1d9b2365d6914e7 upstream.
In RS485 mode, the RTS pin is driven high by hardware when the transmitter
is operating. This behaviour cannot be changed. This means that the driver
should claim that it supports SER_RS485_RTS_ON_SEND and not
SER_RS485_RTS_AFTER_SEND.
Otherwise, when configuring the port with the SER_RS485_RTS_ON_SEND, one
get the following warning:
kern.warning kernel: atmel_usart_serial atmel_usart_serial.2.auto:
ttyS1 (1): invalid RTS setting, using RTS_AFTER_SEND instead
which is contradictory with what's really happening.
Signed-off-by: Mathieu Othacehe <othacehe@xxxxxxx>
Cc: stable <stable@xxxxxxxxxx>
Tested-by: Alexander Dahl <ada@xxxxxxxxxxx>
Fixes: af47c491e3c7 ("serial: atmel: Fill in rs485_supported")
Link: https://lore.kernel.org/r/20240808060637.19886-1-othacehe@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/serial/atmel_serial.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/tty/serial/atmel_serial.c
+++ b/drivers/tty/serial/atmel_serial.c
@@ -2539,7 +2539,7 @@ static const struct uart_ops atmel_pops
};
static const struct serial_rs485 atmel_rs485_supported = {
- .flags = SER_RS485_ENABLED | SER_RS485_RTS_AFTER_SEND | SER_RS485_RX_DURING_TX,
+ .flags = SER_RS485_ENABLED | SER_RS485_RTS_ON_SEND | SER_RS485_RX_DURING_TX,
.delay_rts_before_send = 1,
.delay_rts_after_send = 1,
};
Patches currently in stable-queue which might be from othacehe@xxxxxxx are
queue-6.1/tty-atmel_serial-use-the-correct-rts-flag.patch
