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

From: Geert Uytterhoeven <geert@linux-m68k.org>
To: "Lad, Prabhakar" <prabhakar.csengg@gmail.com>
Cc: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	Rob Herring <robh+dt@kernel.org>,
	Wolfgang Grandegger <wg@grandegger.com>,
	Marc Kleine-Budde <mkl@pengutronix.de>,
	"David S. Miller" <davem@davemloft.net>,
	Jakub Kicinski <kuba@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	linux-can@vger.kernel.org, netdev <netdev@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
	<devicetree@vger.kernel.org>,
	linux-clk <linux-clk@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	Linux-Renesas <linux-renesas-soc@vger.kernel.org>,
	Biju Das <biju.das.jz@bp.renesas.com>
Subject: Re: [PATCH 3/6] dt-bindings: clk: r9a07g044-cpg: Add entry for P0_DIV2 core clock
Date: Fri, 16 Jul 2021 10:56:23 +0200	[thread overview]
Message-ID: <CAMuHMdWBqLcCGWkP9JoALuiXT1m9a1rRwR8ExShUQmJ1HCikZA@mail.gmail.com> (raw)
In-Reply-To: <CA+V-a8v5m-F-n4E9HpwLe1C9gHWepTc0rCVk5oh5RCJ7oTXe2A@mail.gmail.com>

Hi Prabhakar,

On Fri, Jul 16, 2021 at 10:45 AM Lad, Prabhakar
<prabhakar.csengg@gmail.com> wrote:
> On Fri, Jul 16, 2021 at 9:08 AM Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Thu, Jul 15, 2021 at 8:21 PM Lad Prabhakar
> > <prabhakar.mahadev-lad.rj@bp.renesas.com> 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@bp.renesas.com>
> > > Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
> > > ---
> > >  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@linux-m68k.org

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