linux-kernel - Re: [PATCH 3/4] clk: renesas: rzv2h: Re-assert reset on deassert timeout

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Message-ID: <CAMuHMdUC2w_EjBt1D8dqDkASo6xB6TUiu2FpX9tbx=zz+tN=Ow@mail.gmail.com>
Date: Tue, 2 Sep 2025 14:19:16 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
Cc: tomm.merciai@...il.com, linux-renesas-soc@...r.kernel.org, 
	biju.das.jz@...renesas.com, Michael Turquette <mturquette@...libre.com>, 
	Stephen Boyd <sboyd@...nel.org>, Philipp Zabel <p.zabel@...gutronix.de>, linux-clk@...r.kernel.org, 
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] clk: renesas: rzv2h: Re-assert reset on deassert timeout

Hi Tommaso,

On Wed, 20 Aug 2025 at 12:05, Tommaso Merciai
<tommaso.merciai.xr@...renesas.com> wrote:
> Prevent issues during reset deassertion by re-asserting the reset if a
> timeout occurs when trying to deassert. This ensures the reset line is in a
> known state and improves reliability for hardware that may not immediately
> clear the reset monitor bit.
>
> Signed-off-by: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>

Thanks for your patch!

> --- a/drivers/clk/renesas/rzv2h-cpg.c
> +++ b/drivers/clk/renesas/rzv2h-cpg.c
> @@ -865,9 +866,16 @@ static int __rzv2h_cpg_assert(struct reset_controller_dev *rcdev,
>         reg = GET_RST_MON_OFFSET(priv->resets[id].mon_index);
>         mask = BIT(monbit);
>
> -       return readl_poll_timeout_atomic(priv->base + reg, value,
> -                                        assert ? (value & mask) : !(value & mask),
> -                                        10, 200);
> +       ret = readl_poll_timeout_atomic(priv->base + reg, value,
> +                                       assert ? (value & mask) : !(value & mask),
> +                                       10, 200);
> +       if (ret && !assert) {
> +               dev_warn(rcdev->dev, "deassert timeout, re-asserting reset id %ld\n", id);
> +               value = mask << 16;
> +               writel(value, priv->base + GET_RST_OFFSET(priv->resets[id].reset_index));
> +       }

Same questions as for the previous patch:
Is this an issue you've seen during actual use?
Would it make sense to print warnings on assertion timeouts, too?

> +
> +       return ret;
>  }
>
>  static int rzv2h_cpg_assert(struct reset_controller_dev *rcdev,

Reviewed-by: Geert Uytterhoeven <geert+renesas@...der.be>

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