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

Laurent Pinchart
2015-11-20T14:50:03Z

Hi Geert,

On Friday 20 November 2015 10:07:31 Geert Uytterhoeven wrote:
> On Fri, Nov 20, 2015 at 9:58 AM, Laurent Pinchart 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).

That's indeed simpler. Could you capture the behaviour in a source code
comment ?

--
Regards,

Laurent Pinchart