Re: [PATCH RFC] serial: mxs-auart: fix baud rate range

From: Stefan Wahren
Date: Tue Aug 11 2015 - 03:15:25 EST


Hi Janusz,

> Janusz UÅycki <j.uzycki@xxxxxxxxxxxxxxxxxxxxxx> hat am 10. August 2015 um
> 19:01 geschrieben:
>
>
>
>
> W dniu 2015-08-10 o 14:22, Fabio Estevam pisze:
> > On Mon, Aug 10, 2015 at 9:12 AM, Stefan Wahren <stefan.wahren@xxxxxxxx>
> > wrote:
> >
> >> /* set baud rate */
> >> - baud = uart_get_baud_rate(u, termios, old, 0, u->uartclk);
> >> + baud_min = u->uartclk * 32 / 0x3fffc0;
> >> + baud_max = u->uartclk * 32 / 0xec;
> >> + baud = uart_get_baud_rate(u, termios, old, baud_min, baud_max);
> > Looks good. It would be nice to replace 0x3fffc0 and 0xec with defines
> > though.
>
> I agree with Fabio.

i will name them AUART_LINECTRL_BAUD_DIV_MIN and AUART_LINECTRL_BAUD_DIV_MAX.

>
> In addition let's look at the example for uartclk = 24MHz:
> baud_max = 3,254,237.29 => will be rounded down to 3,254,237bauds and it
> is OK
> baud_min = 183.1 => will be rounded to 183 bauds. To avoid div=0x400971
> it should be 184
> so DIV_ROUND_UP() macro could be used.

Thanks for pointing out. I will fix that.

Best regards
Stefan

>
> best regards
> Janusz
>
> >
> > Regards,
> >
> > Fabio Estevam
>
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