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Date:   Thu, 4 Aug 2022 08:51:10 +0200
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Subject: Re: [PATCH 1/1] serial: fsl_lpuart: RS485 RTS polariy is inverse
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To:     Shenwei Wang <shenwei.wang@nxp.com>, gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        NXP Linux Team <linux-imx@nxp.com>,
        Nicolas Diaz <nicolas.diaz@nxp.com>
References: <20220802163854.1055323-1-shenwei.wang@nxp.com>
From:   Jiri Slaby <jirislaby@kernel.org>
In-Reply-To: <20220802163854.1055323-1-shenwei.wang@nxp.com>
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On 02. 08. 22, 18:38, Shenwei Wang wrote:
> 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.

What commit this fixes? I.e. I am missing a Fixes tag below.

> Signed-off-by: Nicolas Diaz <nicolas.diaz@nxp.com>
> Signed-off-by: Shenwei Wang <shenwei.wang@nxp.com>
> ---
>   drivers/tty/serial/fsl_lpuart.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpuart.c
> index afa0f941c862f..abc3a3674bc39 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -1394,9 +1394,9 @@ static int lpuart_config_rs485(struct uart_port *port, struct ktermios *termios,
>   		 * 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;
>   	}
>   
>   	writeb(modem, sport->port.membase + UARTMODEM);

thanks,
-- 
js
suse labs