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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Tue, 5 Mar 2024 15:44:59 +0100
Message-ID: <CAMuHMdWw0dteXO2jw4cwGvzKcL6vmnb96C=qgPgUqNDMtF6X0Q@mail.gmail.com>
Subject: Re: [PATCH] riscv: dts: starfive: replace underscores in node names
To: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Cc: Emil Renner Berthing <kernel@esmil.dk>, Rob Herring <robh@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Paul Walmsley <paul.walmsley@sifive.com>, Palmer Dabbelt <palmer@dabbelt.com>, 
	Albert Ou <aou@eecs.berkeley.edu>, devicetree@vger.kernel.org, 
	linux-riscv@lists.infradead.org, linux-kernel@vger.kernel.org, 
	linux-clk <linux-clk@vger.kernel.org>
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Hi Krzysztof

On Tue, Feb 13, 2024 at 3:48=E2=80=AFPM Krzysztof Kozlowski
<krzysztof.kozlowski@linaro.org> wrote:
> Underscores should not be used in node names (dtc with W=3D2 warns about
> them), so replace them with hyphens.
>
> Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>

Thanks for your patch, which is now commit f03606470886e781 ("riscv:
dts: starfive: replace underscores in node names") in v6.8-rc6.

This causes e.g. BeagleV Starlight to hang during boot without any
output.  Booting with "earlycon" reveals:

    dw-apb-uart 12440000.serial: error -EINVAL: clock rate not defined
    dw-apb-uart: probe of 12440000.serial failed with error -22

and indeed, p->uartclk =3D 0.

> --- a/arch/riscv/boot/dts/starfive/jh7100.dtsi
> +++ b/arch/riscv/boot/dts/starfive/jh7100.dtsi
> @@ -113,28 +113,28 @@ cpu_crit {
>                 };
>         };
>
> -       osc_sys: osc_sys {
> +       osc_sys: osc-sys {
>                 compatible =3D "fixed-clock";
>                 #clock-cells =3D <0>;
>                 /* This value must be overridden by the board */
>                 clock-frequency =3D <0>;
>         };
>
> -       osc_aud: osc_aud {
> +       osc_aud: osc-aud {
>                 compatible =3D "fixed-clock";
>                 #clock-cells =3D <0>;
>                 /* This value must be overridden by the board */
>                 clock-frequency =3D <0>;
>         };
>
> -       gmac_rmii_ref: gmac_rmii_ref {
> +       gmac_rmii_ref: gmac-rmii-ref {
>                 compatible =3D "fixed-clock";
>                 #clock-cells =3D <0>;
>                 /* Should be overridden by the board when needed */
>                 clock-frequency =3D <0>;
>         };
>
> -       gmac_gr_mii_rxclk: gmac_gr_mii_rxclk {
> +       gmac_gr_mii_rxclk: gmac-gr-mii-rxclk {
>                 compatible =3D "fixed-clock";
>                 #clock-cells =3D <0>;
>                 /* Should be overridden by the board when needed */

The clock driver relies on the clock names, which are (in the absence
of clock-output-names properties) identical to the actual node names:

drivers/clk/starfive/clk-starfive-jh7100.c:    parents[i].fw_name =3D "osc_=
sys";
drivers/clk/starfive/clk-starfive-jh7100.c:    parents[i].fw_name =3D "osc_=
aud";
drivers/clk/starfive/clk-starfive-jh7100.c:    parents[i].fw_name =3D
"gmac_rmii_ref";
drivers/clk/starfive/clk-starfive-jh7100.c:    parents[i].fw_name =3D
"gmac_gr_mii_rxclk";

Hence these clocks can no longer be found, and all children have a
zero clock rate, causing the breakage.

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds