Hi Biju,
On Thu, Oct 24, 2024 at 1:51 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > From: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > On Wed, Oct 16, 2024 at 12:15 PM Biju Das <biju.das.jz@xxxxxxxxxxxxxx> wrote:
> > > While computing foutpostdiv_rate, the value of params->pl5_fracin is
> > > discarded, which results in the wrong refresh rate. Fix the formula
> > > for computing foutpostdiv_rate.
> > >
> > > Fixes: 1561380ee72f ("clk: renesas: rzg2l: Add FOUTPOSTDIV clk
> > > support")
> > > Signed-off-by: Hien Huynh <hien.huynh.px@xxxxxxxxxxx>
> > > Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > > ---
> > > v2->v3:
> > > * Used mul_u32_u32() for 32-bit multiplication.
> >
> > Thanks for the update!
> >
> > > --- a/drivers/clk/renesas/rzg2l-cpg.c
> > > +++ b/drivers/clk/renesas/rzg2l-cpg.c
> > > @@ -557,10 +557,10 @@ rzg2l_cpg_get_foutpostdiv_rate(struct rzg2l_pll5_param *params,
> > > params->pl5_postdiv2 = 1;
> > > params->pl5_spread = 0x16;
> > >
> > > - foutpostdiv_rate =
> > > - EXTAL_FREQ_IN_MEGA_HZ * MEGA / params->pl5_refdiv *
> > > - ((((params->pl5_intin << 24) + params->pl5_fracin)) >> 24) /
> > > - (params->pl5_postdiv1 * params->pl5_postdiv2);
> > > + foutvco_rate = mul_u32_u32(EXTAL_FREQ_IN_MEGA_HZ * MEGA, (params->pl5_intin << 24) +
> > > + params->pl5_fracin) /
> > > + params->pl5_refdiv >> 24;
>
> >
> > The division is a 64-by-32 division, so it should use the div_u64() helper.
>
> You mean,
>
> foutvco_rate = div_u64(mul_u32_u32(EXTAL_FREQ_IN_MEGA_HZ * MEGA, (params->pl5_intin << 24) +
> params->pl5_fracin) , params->pl5_refdiv) >> 24; ??
Exactly.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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
