Subject: [PATCH 2/2] tty: serial: imx: don't reinit clock with enabled console

From: [email-masked] (Troy Kisky)
Date: Mon, 27 Aug 2012 11:20:10 -0700

On 8/27/2012 12:36 AM, Dirk Behme wrote:
> From: Xinyu Chen <[email-masked]>
>
> 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 <[email-masked]>
> Tested-by: Dirk Behme <[email-masked]>
> CC: Shawn Guo <[email-masked]>
> CC: Sascha Hauer <[email-masked]>
> ---
>   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