Re: [PATCH 3/6] dt-bindings: clk: r9a07g044-cpg: Add entry for P0_DIV2 core clock

From: Geert Uytterhoeven
Date: Fri Jul 16 2021 - 04:58:01 EST


Hi Prabhakar,

On Fri, Jul 16, 2021 at 10:45 AM Lad, Prabhakar
<prabhakar.csengg@xxxxxxxxx> wrote:
> On Fri, Jul 16, 2021 at 9:08 AM Geert Uytterhoeven <geert@xxxxxxxxxxxxxx> wrote:
> > On Thu, Jul 15, 2021 at 8:21 PM Lad Prabhakar
> > <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx> wrote:
> > > Add P0_DIV2 core clock required for CANFD module. CANFD core clock is
> > > sourced from P0_DIV2 referenced from HW manual Rev.0.50.
> >
> > OK.
> >
> > > Also add R9A07G044_LAST_CORE_CLK entry to avoid changes in
> > > r9a07g044-cpg.c file.
> >
> > I'm not so fond of adding this. Unlike the other definitions, it is
> > not really part of the bindings, but merely a convenience definition
> > for the driver. Furthermore it has to change when a new definition
> > is ever added.
> >
> Agreed will drop this.
>
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@xxxxxxxxxxxxxx>
> > > Reviewed-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> > > ---
> > > include/dt-bindings/clock/r9a07g044-cpg.h | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/include/dt-bindings/clock/r9a07g044-cpg.h b/include/dt-bindings/clock/r9a07g044-cpg.h
> > > index 0728ad07ff7a..2fd20db0b2f4 100644
> > > --- a/include/dt-bindings/clock/r9a07g044-cpg.h
> > > +++ b/include/dt-bindings/clock/r9a07g044-cpg.h
> > > @@ -30,6 +30,8 @@
> > > #define R9A07G044_CLK_P2 19
> > > #define R9A07G044_CLK_AT 20
> > > #define R9A07G044_OSCCLK 21
> > > +#define R9A07G044_CLK_P0_DIV2 22
> > > +#define R9A07G044_LAST_CORE_CLK 23
> >
> > Third issue: off-by-one error, it should be 22 ;-)
> >
> 23 was intentionally as these numbers aren't used for core clock count
> we use r9a07g044_core_clks[] instead.

It ends up as an off-by-one bug in the range check in
rzg2l_cpg_clk_src_twocell_get().

> Said that I'll drop this.

OK.

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