linux-kernel - Re: [PATCH 2/2] clocksource/drivers/renesas-ostm: Add OSTM support for RZ/V2H(P) SoC

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Date: Tue, 19 Mar 2024 09:33:43 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Prabhakar <prabhakar.csengg@...il.com>
Cc: Daniel Lezcano <daniel.lezcano@...aro.org>, Thomas Gleixner <tglx@...utronix.de>, 
	Rob Herring <robh+dt@...nel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>, Conor Dooley <conor+dt@...nel.org>, 
	Chris Brandt <chris.brandt@...esas.com>, Magnus Damm <magnus.damm@...il.com>, 
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-renesas-soc@...r.kernel.org, 
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>, 
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
Subject: Re: [PATCH 2/2] clocksource/drivers/renesas-ostm: Add OSTM support
 for RZ/V2H(P) SoC

Hi Prabhakar,

Thanks for your patch!

On Mon, Mar 18, 2024 at 5:08 PM Prabhakar <prabhakar.csengg@...il.com> wrote:
> From: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>
>
> RZ/V2H(P) (R9A09G057) SoC has Generic Timer Module(a.k.a OSTM) which
> needs to deassert the reset line before accessing any registers just
> like the RZ/G2L SoC.
>
> Enable the entry point for RZ/V2H(P) SoC so that we can deassert
> the reset line in probe callback.

This is not really what is happening.
As OSTM on RZ/V2H has a reset specified, the early call to ostm_init()
through TIMER_OF_DECLARE() always fails with -EPROBE_DEFER, as resets
are not available that early in the boot process.  Hence the driver
needs to be reprobed later through the platform driver probe.

> While at it use IS_ENABLED() macro instead of open coding.

I don't see how the code was open-coding IS_ENABLED()?

>
> Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>

> --- a/drivers/clocksource/renesas-ostm.c
> +++ b/drivers/clocksource/renesas-ostm.c
> @@ -224,7 +224,7 @@ static int __init ostm_init(struct device_node *np)
>
>  TIMER_OF_DECLARE(ostm, "renesas,ostm", ostm_init);
>
> -#ifdef CONFIG_ARCH_RZG2L
> +#if IS_ENABLED(CONFIG_ARCH_RZG2L) || IS_ENABLED(CONFIG_ARCH_R9A09G057)

I think you want to use "defined()" instead of "IS_ENABLED()"?

>  static int __init ostm_probe(struct platform_device *pdev)
>  {
>         struct device *dev = &pdev->dev;

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68korg

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