Re: [PATCH 00/25] serial: sh-sci: Add external clock and BRG Support

Geert Uytterhoeven
2015-11-20T09:07:42Z

Hi Laurent,

On Fri, Nov 20, 2015 at 9:58 AM, Laurent Pinchart
<laurent.pinchart@ideasonboard.com> wrote:
> On Friday 20 November 2015 09:22:16 Geert Uytterhoeven wrote:
>> On Thu, Nov 19, 2015 at 10:08 PM, Laurent Pinchart wrote:
>> > Could you briefly explain (and even better in a source code comment) how
>> > you handle baud rate calculation with the chained BRGs ?
>>
>> I'll do that. Note that there's no chaining of BRGs, only muxing (so yes, it
>> needs more clarification ;-).
>
> Really ? I thought the BRG-EC was one possible input for the internal BRG ?
> Does it bypass the internal BRG ? Or do you configure the internal BRG to not
> divide the clock when using the BRG-EC ?

Yes, it's bypassed.

Cfr. SCSCR.CKE[1:0].
'00' means internal BRG (although the docs state P divided by 1/4/16/64),
'10' means SCK or SC_CLK (SCIF_CLK/INT_CLK).

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds