linux-kernel - Re: [PATCH v2 2/2] clocksource/drivers/renesas-ostm: Enable reprobe for all ARM64 SoCs

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Message-ID: <CAMuHMdWJ+Qcmj3aCEsd5Ydr9qn4hsr013w_ffjzj=jhtS9YFtQ@mail.gmail.com>
Date: Fri, 2 May 2025 19:36:10 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: "Lad, Prabhakar" <prabhakar.csengg@...il.com>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>, Thomas Gleixner <tglx@...utronix.de>, 
	Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, 
	Maxime Coquelin <mcoquelin.stm32@...il.com>, Alexandre Torgue <alexandre.torgue@...s.st.com>, 
	Geert Uytterhoeven <geert+renesas@...der.be>, Magnus Damm <magnus.damm@...il.com>, 
	Chris Brandt <chris.brandt@...esas.com>, linux-kernel@...r.kernel.org, 
	devicetree@...r.kernel.org, linux-stm32@...md-mailman.stormreply.com, 
	linux-arm-kernel@...ts.infradead.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 v2 2/2] clocksource/drivers/renesas-ostm: Enable reprobe
 for all ARM64 SoCs

Hi Prabhakar,

On Fri, 2 May 2025 at 18:10, Lad, Prabhakar <prabhakar.csengg@...il.com> wrote:
> On Fri, May 2, 2025 at 3:37 PM Geert Uytterhoeven <geert@...ux-m68k.org> wrote:
> > On Fri, 2 May 2025 at 14:47, Prabhakar <prabhakar.csengg@...il.com> wrote:
> > > From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > >
> > > Change the OSTM driver's probe condition to `CONFIG_ARM64` so that the
> > > platform driver will defer and reprobe on any ARM64 Renesas SoC once its
> > > reset controller is available. Previously, only RZ/G2L and RZ/V2H(P)
> > > were covered.
> > >
> > > By matching on `CONFIG_ARM64`, this avoids adding a new config entry
> > > for each future ARM64 Renesas SoC with OSTM IP. RZ/A1 and RZ/A2 (ARM32)
> > > are unaffected-they still use OSTM but do not define a resets property,
> > > so the deferred reprobe mechanism is unnecessary.
> > >
> > > Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
> > > Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>
> > > ---
> > > Hi Geert,
> > > I've restored the Reviewed-by tag from v1 with your suggestions applied.
> > > I hope you're okay with this.
> > > Cheers, Prabhakar
> > >
> > > v1->v2:
> > > - Instead of adding config for new SoC, changed the probe condition to
> > >   `CONFIG_ARM64`.
> > > - Updated commit message
> > > - Added a Reviewed-by tag from Geert.
> > > ---
> > >  drivers/clocksource/renesas-ostm.c | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/clocksource/renesas-ostm.c b/drivers/clocksource/renesas-ostm.c
> > > index 3fcbd02b2483..6a5785f9c9c1 100644
> > > --- a/drivers/clocksource/renesas-ostm.c
> > > +++ b/drivers/clocksource/renesas-ostm.c
> > > @@ -225,7 +225,7 @@ static int __init ostm_init(struct device_node *np)
> > >
> > >  TIMER_OF_DECLARE(ostm, "renesas,ostm", ostm_init);
> > >
> > > -#if defined(CONFIG_ARCH_RZG2L) || defined(CONFIG_ARCH_R9A09G057)
> > > +#if defined(CONFIG_ARM64)
> >
> > Sorry, I've just realized RZ/Five also wants this.
> >
> Ouch, I missed that too.
>
> > "#ifndef CONFIG_ARM"?
> >
> Im wondering will it harm if we have it enabled for ARM too (I dont
> have RZ/Ax to test it)?

ISTR it caused issues on RZ/Ax.

Oh right, and those got fixed by commit 37385c0772a4fc6b
("clocksource/drivers/renesas-ostm: Avoid reprobe after successful
early probe") in v6.10. So I think it is safe to drop the #ifdef
check instead of extending it.

FTR, with the platform probe enabled, and 37385c0772a4fc6b reverted:

    /soc/timer@...3b000: used for clock events
    genirq: Flags mismatch irq 16. 00215201 (timer@...3c000) vs.
00215201 (timer@...3c000)
    Failed to request irq 16 for /soc/timer@...3c000
    renesas_ostm e803c000.timer: probe with driver renesas_ostm failed
with error -16

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