From mboxrd@z Thu Jan  1 00:00:00 1970
From: Troy Kisky <troy.kisky@boundarydevices.com>
Subject: Re: [PATCH 2/2] tty: serial: imx: don't reinit clock with enabled
 console
Date: Mon, 27 Aug 2012 11:20:10 -0700
Message-ID: <503BBA5A.8040609@boundarydevices.com>
References: <1346053012-25686-1-git-send-email-dirk.behme@de.bosch.com> <1346053012-25686-3-git-send-email-dirk.behme@de.bosch.com>
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To: Dirk Behme <dirk.behme@de.bosch.com>
Cc: linux-arm-kernel@lists.infradead.org, linux-serial@vger.kernel.org, kernel@pengutronix.de, Greg Kroah-Hartman <gregkh@linuxfoundation.org>, Sascha Hauer <s.hauer@pengutronix.de>, Xinyu Chen <xinyu.chen@freescale.com>, Shawn Guo <shawn.guo@linaro.org>, Alan Cox <alan@linux.intel.com>

On 8/27/2012 12:36 AM, Dirk Behme wrote:
> From: Xinyu Chen <xinyu.chen@freescale.com>
>
> Remove the imx_setup_ufcr() call on startup when CONSOLE enabled,
> as this will cause clock reinit, and output garbage.
>
> This patch is a port from Freescale's Android kernel.
>
> Signed-off-by: Xinyu Chen <xinyu.chen@freescale.com>
> Tested-by: Dirk Behme <dirk.behme@de.bosch.com>
> CC: Shawn Guo <shawn.guo@linaro.org>
> CC: Sascha Hauer <s.hauer@pengutronix.de>
> ---
>   drivers/tty/serial/imx.c |    2 ++
>   1 files changed, 2 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/tty/serial/imx.c b/drivers/tty/serial/imx.c
> index 908178f..31ce414 100644
> --- a/drivers/tty/serial/imx.c
> +++ b/drivers/tty/serial/imx.c
> @@ -695,7 +695,9 @@ static int imx_startup(struct uart_port *port)
>   	int retval;
>   	unsigned long flags, temp;
>   
> +#ifndef CONFIG_SERIAL_CORE_CONSOLE
>   	imx_setup_ufcr(sport, 0);
> +#endif
>   
>   	/* disable the DREN bit (Data Ready interrupt enable) before
>   	 * requesting IRQs


I'd rather do something like this

static int imx_setup_ufcr(struct imx_port *sport, unsigned int mode)
{
         unsigned int val;

         /* set receiver / transmitter trigger level. */
         val = readl(sport->port.membase + UFCR) & UFCR_RFDIV;
         val |= TXTL << 10 | RXTL;
         writel(val, sport->port.membase + UFCR);
         return 0;
}

There is no need for imx_setup_ufcr to change divisor.


Troy