linux-kernel - Re: [PATCH] dt-bindings: mmc: renesas,sdhi: Document RZ/T2H and RZ/N2H support

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Message-ID: <CAMuHMdU9506cHe5xyMSfu_AX_i7k+GupuaaAKDNH6LA9hEXNPA@mail.gmail.com>
Date: Tue, 17 Jun 2025 09:11:17 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
Cc: Ulf Hansson <ulf.hansson@...aro.org>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Magnus Damm <magnus.damm@...il.com>, Wolfram Sang <wsa+renesas@...g-engineering.com>, 
	linux-mmc@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-kernel@...r.kernel.org, linux-renesas-soc@...r.kernel.org, 
	Biju Das <biju.das.jz@...renesas.com>, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH] dt-bindings: mmc: renesas,sdhi: Document RZ/T2H and
 RZ/N2H support

Hi Prabhakar,

On Fri, 13 Jun 2025 at 20:59, Lad, Prabhakar <prabhakar.csengg@...il.com> wrote:
> On Fri, Jun 13, 2025 at 4:37 PM Lad, Prabhakar <prabhakar.csengg@...il.com> wrote:
> > On Thu, Jun 12, 2025 at 4:47 PM Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> > > On Tue, 10 Jun 2025 at 01:23, Prabhakar <prabhakar.csengg@...il.com> wrote:
> > > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > > >
> > > > Add SDHI bindings for the Renesas RZ/T2H (a.k.a R9A09G077) and RZ/N2H
> > > > (a.k.a R9A09G087) SoCs. Use `renesas,sdhi-r9a09g057` as a fallback since
> > > > the SD/MMC block on these SoCs is identical to the one on RZ/V2H(P),
> > > > allowing reuse of the existing driver without modifications.
> > > >
> > > > Update the binding schema to reflect differences: unlike RZ/V2H(P),
> > > > RZ/T2H and RZ/N2H do not require the `resets` property and use only a
> > > > single clock instead of four.
> > > >
> > > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > >
> > > Thanks for your patch!
> > >
> > > > --- a/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
> > > > +++ b/Documentation/devicetree/bindings/mmc/renesas,sdhi.yaml
> > > > @@ -129,59 +131,75 @@ allOf:
> > > >          compatible:
> > > >            contains:
> > > >              enum:
> > > > -              - renesas,sdhi-r9a09g057
> > > > -              - renesas,rzg2l-sdhi
> > > > +              - renesas,sdhi-r9a09g077
> > > > +              - renesas,sdhi-r9a09g087
> > > >      then:
> > > >        properties:
> > > > +        resets: false
> > > >          clocks:
> > > > -          items:
> > > > -            - description: IMCLK, SDHI channel main clock1.
> > > > -            - description: CLK_HS, SDHI channel High speed clock which operates
> > > > -                           4 times that of SDHI channel main clock1.
> > > > -            - description: IMCLK2, SDHI channel main clock2. When this clock is
> > > > -                           turned off, external SD card detection cannot be
> > > > -                           detected.
> > > > -            - description: ACLK, SDHI channel bus clock.
> > > > +          description: ACLK, SDHI channel bus clock.
> > >
> > > According to the documentation, this is the SDHI high speed clock...
> > >
> Actually re-reading the doc there are two clocks (I had missed the
> second clock earlier),

And I had missed the first, as it is not shown in Figure 7.1
("Block diagram of clock generation circuit" ;-)

> 1] ACLK, IMCLK from the PCLKAM which is 200MHz
> 2] SDHI_clkhs from PLL2 which is 800MHz
> Note, on RZ/V2H too the ACLK/IMCLK is 200MHz and clk_hs is 800MHz
>
> So, I'll represent them as below:
>         clocks:
>           items:
>             - description: ACLK, IMCLK, SDHI channel bus and main clocks.
>             - description: CLK_HS, SDHI channel High speed clock.
>         clock-names:
>           items:
>             - const: aclk
>             - const: clkh
>
> And for the ACLK, IMCLK which comes from peripheral module clock
> (PCLKAM) this will be a module clock and CLK_HS will have to be
> modelled as a CORE clock.

OK.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-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