linux-kernel - Re: [PATCH net] net: mdio_bus: Use devm for getting reset GPIO

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Message-ID: <CAMuHMdVdsZtRpbbWsRC_YSYgGojA-wxdxRz7eytJvc+xq2uqEw@mail.gmail.com>
Date: Fri, 1 Aug 2025 14:25:17 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Mark Brown <broonie@...nel.org>
Cc: Bence Csókás <csokas.bence@...lan.hu>, 
	Sergei Shtylyov <sergei.shtylyov@...entembedded.com>, 
	"David S. Miller" <davem@...emloft.net>, Rob Herring <robh@...nel.org>, Andrew Lunn <andrew@...n.ch>, 
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>, 
	Dmitry Torokhov <dmitry.torokhov@...il.com>, netdev@...r.kernel.org, 
	linux-kernel@...r.kernel.org, Csaba Buday <buday.csaba@...lan.hu>, 
	Heiner Kallweit <hkallweit1@...il.com>, Russell King <linux@...linux.org.uk>, 
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, Paolo Abeni <pabeni@...hat.com>
Subject: Re: [PATCH net] net: mdio_bus: Use devm for getting reset GPIO

Hi Mark,

On Fri, 1 Aug 2025 at 14:01, Mark Brown <broonie@...nel.org> wrote:
> On Mon, Jul 28, 2025 at 05:34:55PM +0200, Bence Csókás wrote:
> > Commit bafbdd527d56 ("phylib: Add device reset GPIO support") removed
> > devm_gpiod_get_optional() in favor of the non-devres managed
> > fwnode_get_named_gpiod(). When it was kind-of reverted by commit
> > 40ba6a12a548 ("net: mdio: switch to using gpiod_get_optional()"), the devm
> > functionality was not reinstated. Nor was the GPIO unclaimed on device
> > remove. This leads to the GPIO being claimed indefinitely, even when the
> > device and/or the driver gets removed.
>
> I'm seeing multiple platforms including at least Beaglebone Black,
> Tordax Mallow and Libre Computer Alta printing errors in
> next/pending-fixes today:
>
> [    3.252885] mdio_bus 4a101000.mdio:00: Resources present before probing
>
> Bisects are pointing to this patch which is 3b98c9352511db in -next,

My guess is that &mdiodev->dev is not the correct device for
resource management.
We had a similar issue before with non-GPIO resets, cfr. commit
32085f25d7b68404 ("mdio_bus: don't use managed reset-controller").

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