Re: [PATCH] drm/omap: Migrate minimum FCK/PCK ratio from Kconfig to dts

[Adam Ford]

On Tue, Oct 1, 2019 at 4:31 AM Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
>
> On 01/10/2019 11:12, Tero Kristo wrote:
> > On 01/10/2019 08:07, Tomi Valkeinen wrote:
> >> On 30/09/2019 20:48, Tero Kristo wrote:
> >>
> >>> Hmmh, after some testing, it seems there is bad stuff happening with
> >>> the divider clock implementation, I am re-working it as of now.
> >>> Basically what is wrong is that with a divider max value of say 16,
> >>> the driver attempts to craft the max value into a mask, but this ends
> >>> up being 0x1f. If the max value is 15, it ends up into 0xf which is
> >>> correct.
> >>
> >> Ok, that explains the max not working.
> >>
> >> It doesn't explain the other issue, where the TRM says the max div is
> >> 32, but it does not work. But taking the max div from the old SoCs,
> >> 16, is not correct either, as it seems that dividers up to 31 work ok.
> >>
> >>   Tomi
> >>
> >
> > Ok, attached a series that hopefully fixes it, any testing feedback
> > welcome before I post this properly.
> >
> > This also supports omap36xx dpll4_m4_ck divider up-to 31, other omap3
> > family is limited to 16.

Thank you!  This works for me.

>
> Works for me. This also needs the change to dss.c to change the max from
> 32 to 31. I'll send a patch for that separately.

Tomi,

Do you want me to push a patch to remove the
CONFIG_OMAP2_DSS_MIN_FCK_PER_PCK hack once these patches have been
posted?  It seems like the divider fix eliminates the need for this
hack.

adam
>
>   Tomi
>
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