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From:   Andy Duan <fugang.duan@nxp.com>
To:     Philippe Schenker <philippe.schenker@toradex.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        "linux-serial@vger.kernel.org" <linux-serial@vger.kernel.org>
CC:     Max Krummenacher <max.krummenacher@toradex.com>,
        Jiri Slaby <jslaby@suse.com>,
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        Stefan Agner <stefan@agner.ch>,
        dl-linux-imx <linux-imx@nxp.com>,
        Andrey Smirnov <andrew.smirnov@gmail.com>
Subject: RE: [EXT] [PATCH v1 1/3] tty: serial: lpuart: Remove unnecessary code
 from set_mctrl
Thread-Topic: [EXT] [PATCH v1 1/3] tty: serial: lpuart: Remove unnecessary
 code from set_mctrl
Thread-Index: AQHVhDUGhND3HaeiCUSQsk6nHPAtXKdeSnjQ
Date:   Thu, 17 Oct 2019 05:13:14 +0000
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References: <20191016151845.15859-1-philippe.schenker@toradex.com>
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From: Philippe Schenker <philippe.schenker@toradex.com> Sent: Wednesday, Oc=
tober 16, 2019 11:19 PM
> Currently flow control is not working due to lpuart32_set_mctrl that is
> clearing TXCTSE bit in all cases. This bit gets earlier setup by
> lpuart32_set_termios.
>=20
> As I read in Documentation set_mctrl is also not meant for hardware flow
> control rather than gpio setting and clearing a RTS signal.
> Therefore I guess it is safe to remove the whole code in lpuart32_set_mct=
rl.
>=20
> This was tested with console on a i.MX8QXP SoC.
>=20
> Signed-off-by: Philippe Schenker <philippe.schenker@toradex.com>

Reviewed-by: Fugang Duan <fugang.duan@nxp.com>
> ---
>=20
>  drivers/tty/serial/fsl_lpuart.c | 11 -----------
>  1 file changed, 11 deletions(-)
>=20
> diff --git a/drivers/tty/serial/fsl_lpuart.c b/drivers/tty/serial/fsl_lpu=
art.c index
> 537896c4d887..f3271857621c 100644
> --- a/drivers/tty/serial/fsl_lpuart.c
> +++ b/drivers/tty/serial/fsl_lpuart.c
> @@ -1333,18 +1333,7 @@ static void lpuart_set_mctrl(struct uart_port
> *port, unsigned int mctrl)
>=20
>  static void lpuart32_set_mctrl(struct uart_port *port, unsigned int mctr=
l)  {
> -       unsigned long temp;
> -
> -       temp =3D lpuart32_read(port, UARTMODIR) &
> -                       ~(UARTMODIR_RXRTSE |
> UARTMODIR_TXCTSE);
> -
> -       if (mctrl & TIOCM_RTS)
> -               temp |=3D UARTMODIR_RXRTSE;
> -
> -       if (mctrl & TIOCM_CTS)
> -               temp |=3D UARTMODIR_TXCTSE;
>=20
> -       lpuart32_write(port, temp, UARTMODIR);
>  }
>=20
>  static void lpuart_break_ctl(struct uart_port *port, int break_state)
> --
> 2.23.0