This is a note to let you know that I've just added the patch titled serial: fsl_lpuart: RS485 RTS polariy is inverse to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: serial-fsl_lpuart-rs485-rts-polariy-is-inverse.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 846651eca073e2e02e37490a4a52752415d84781 Mon Sep 17 00:00:00 2001 From: Shenwei Wang <shenwei.wang@xxxxxxx> Date: Fri, 5 Aug 2022 09:45:29 -0500 Subject: serial: fsl_lpuart: RS485 RTS polariy is inverse From: Shenwei Wang <shenwei.wang@xxxxxxx> commit 846651eca073e2e02e37490a4a52752415d84781 upstream. The setting of RS485 RTS polarity is inverse in the current driver. When the property of 'rs485-rts-active-low' is enabled in the dts node, the RTS signal should be LOW during sending. Otherwise, if there is no such a property, the RTS should be HIGH during sending. Fixes: 03895cf41d18 ("tty: serial: fsl_lpuart: Add support for RS-485") Cc: stable <stable@xxxxxxxxxx> Signed-off-by: Nicolas Diaz <nicolas.diaz@xxxxxxx> Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxx> Link: https://lore.kernel.org/r/20220805144529.604856-1-shenwei.wang@xxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/tty/serial/fsl_lpuart.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/tty/serial/fsl_lpuart.c +++ b/drivers/tty/serial/fsl_lpuart.c @@ -951,9 +951,9 @@ static int lpuart_config_rs485(struct ua * Note: UART is assumed to be active high. */ if (rs485->flags & SER_RS485_RTS_ON_SEND) - modem &= ~UARTMODEM_TXRTSPOL; - else if (rs485->flags & SER_RS485_RTS_AFTER_SEND) modem |= UARTMODEM_TXRTSPOL; + else if (rs485->flags & SER_RS485_RTS_AFTER_SEND) + modem &= ~UARTMODEM_TXRTSPOL; } /* Store the new configuration */ Patches currently in stable-queue which might be from shenwei.wang@xxxxxxx are queue-4.9/serial-fsl_lpuart-rs485-rts-polariy-is-inverse.patch