Re: [PATCH] fbdev/omap: fix max fclk divider for omap36xx

[Adam Ford]

On Mon, Oct 21, 2019 at 3:42 AM Tomi Valkeinen <tomi.valkeinen@xxxxxx> wrote:
>
> On 18/10/2019 15:49, Adam Ford wrote:
> > The OMAP36xx and AM/DM37x TRMs say that the maximum divider for DSS fclk
> > (in CM_CLKSEL_DSS) is 32. Experimentation shows that this is not
> > correct, and using divider of 32 breaks DSS with a flood or underflows
> > and sync losts. Dividers up to 31 seem to work fine.
> >
> > There is another patch to the DT files to limit the divider correctly,
> > but as the DSS driver also needs to know the maximum divider to be able
> > to iteratively find good rates, we also need to do the fix in the DSS
> > driver.
> >
> > Signed-off-by: Adam Ford <aford173@xxxxxxxxx>
> > Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
> > Cc: stable@xxxxxxxxxxxxxxx #linux-4.9.y+
> >
> > diff --git a/drivers/video/fbdev/omap2/omapfb/dss/dss.c b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > index 48c6500c24e1..4429ad37b64c 100644
> > --- a/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > +++ b/drivers/video/fbdev/omap2/omapfb/dss/dss.c
> > @@ -843,7 +843,7 @@ static const struct dss_features omap34xx_dss_feats = {
> >   };
> >
> >   static const struct dss_features omap3630_dss_feats = {
> > -     .fck_div_max            =       32,
> > +     .fck_div_max            =       31,
> >       .dss_fck_multiplier     =       1,
> >       .parent_clk_name        =       "dpll4_ck",
> >       .dpi_select_source      =       &dss_dpi_select_source_omap2_omap3,
> >
>
> Reviewed-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx>

What is the next step to get these integrated into 4.9+?

adam
>
>   Tomi
>
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