linux-kernel - Re: [PATCH v3 2/2] clk: renesas: r9a09g057-cpg: Add clock and reset entries for GTM/RIIC/SDHI/WDT

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Message-ID: <CA+V-a8tW0wmpu807Vxi_e49JraoNry1Anb_Ys7rM=CpODkpKeA@mail.gmail.com>
Date: Wed, 28 Aug 2024 11:20:05 +0100
From: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
To: Biju Das <biju.das.jz@...renesas.com>
Cc: Geert Uytterhoeven <geert+renesas@...der.be>, Michael Turquette <mturquette@...libre.com>, 
	Stephen Boyd <sboyd@...nel.org>, 
	"linux-renesas-soc@...r.kernel.org" <linux-renesas-soc@...r.kernel.org>, 
	"linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Prabhakar Mahadev Lad <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH v3 2/2] clk: renesas: r9a09g057-cpg: Add clock and reset
 entries for GTM/RIIC/SDHI/WDT

On Wed, Aug 28, 2024 at 11:10 AM Biju Das <biju.das.jz@...renesas.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Lad, Prabhakar <prabhakar.csengg@...il.com>
> > Sent: Wednesday, August 28, 2024 11:00 AM
> > Subject: Re: [PATCH v3 2/2] clk: renesas: r9a09g057-cpg: Add clock and reset entries for
> > GTM/RIIC/SDHI/WDT
> >
> > Hi Biju,
> >
> > On Wed, Aug 28, 2024 at 10:53 AM Biju Das <biju.das.jz@...renesas.com> wrote:
> > >
> > > Hi Prabhakar,
> > >
> > > Thanks for the patch.
> > >
> > > > -----Original Message-----
> > > > From: Prabhakar <prabhakar.csengg@...il.com>
> > > > Sent: Wednesday, August 28, 2024 10:38 AM
> > > > Subject: [PATCH v3 2/2] clk: renesas: r9a09g057-cpg: Add clock and reset entries for
> > GTM/RIIC/SDHI/WDT
> > > >
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > > >
> > > > Add clock and reset entries for GTM, RIIC, SDHI and WDT IP blocks.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > > > ---
> > > > v2->v3
> > > > - Moved DDIV_PACK() macro to patch #1
> > > >
> > > > v1->v2
> > > > - Updated DDIV_PACK macro to accommodate width
> > > > ---
> > > >  drivers/clk/renesas/r9a09g057-cpg.c | 84 +++++++++++++++++++++++++++++
> > > >  drivers/clk/renesas/rzv2h-cpg.h     |  4 ++
> > > >  2 files changed, 88 insertions(+)
> > > >
> > > > diff --git a/drivers/clk/renesas/r9a09g057-cpg.c b/drivers/clk/renesas/r9a09g057-cpg.c
> > > > index 9722b810e027..3ee32db5c0af 100644
> > > > --- a/drivers/clk/renesas/r9a09g057-cpg.c
> > > > +++ b/drivers/clk/renesas/r9a09g057-cpg.c
> > > > @@ -25,16 +25,31 @@ enum clk_ids {
> > > >
> > > >       /* PLL Clocks */
> > > >       CLK_PLLCM33,
> > > > +     CLK_PLLCLN,
> > > >       CLK_PLLDTY,
> > > >       CLK_PLLCA55,
> > > >
> > > >       /* Internal Core Clocks */
> > > >       CLK_PLLCM33_DIV16,
> > > > +     CLK_PLLCLN_DIV2,
> > > > +     CLK_PLLCLN_DIV8,
> > > > +     CLK_PLLCLN_DIV16,
> > > > +     CLK_PLLDTY_ACPU,
> > > > +     CLK_PLLDTY_ACPU_DIV4,
> > > >
> > > >       /* Module Clocks */
> > > >       MOD_CLK_BASE,
> > > >  };
> > > >
> > > > +static const struct clk_div_table dtable_2_64[] = {
> > > > +     {0, 2},
> > > > +     {1, 4},
> > > > +     {2, 8},
> > > > +     {3, 16},
> > > > +     {4, 64},
> > > > +     {0, 0},
> > >
> > > Is it ok to have {0, 2} first entry and {0, 0} last entry on the same table?
> > >
> > You mean is it prohibited to add (I haven't seen issues)?
>
> 2 different divider values{2, 0) for the value 0 in the table. You maybe correct.
>
AFAIK we add sentinel entry at the end of clk_div_table[], see below

https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/clk/renesas/rcar-gen4-cpg.c?h=next-20240828#n415
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/clk/renesas/r9a07g044-cpg.c?h=next-20240828#n80
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/clk/renesas/rcar-gen2-cpg.c?h=next-20240828#n202
https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/clk/renesas/rcar-gen3-cpg.c?h=next-20240828#n327

Cheers,
Prabhakar