linux-kernel - Re: [PATCH] pinctrl: meson: amlogic-a4: mark the GPIO controller as sleeping

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Message-ID: <CAMRc=Me+mgRZ4thXnYFUv42hQBV36hM5DUckM8U_VQa8chNehw@mail.gmail.com>
Date: Tue, 6 Jan 2026 11:40:30 +0100
From: Bartosz Golaszewski <brgl@...nel.org>
To: Xianwei Zhao <xianwei.zhao@...ogic.com>
Cc: Neil Armstrong <neil.armstrong@...aro.org>, 
	Bartosz Golaszewski <bartosz.golaszewski@....qualcomm.com>, Linus Walleij <linusw@...nel.org>, 
	Kevin Hilman <khilman@...libre.com>, Jerome Brunet <jbrunet@...libre.com>, 
	Martin Blumenstingl <martin.blumenstingl@...glemail.com>, linux-gpio@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-amlogic@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] pinctrl: meson: amlogic-a4: mark the GPIO controller as sleeping

On Tue, Jan 6, 2026 at 10:32 AM Xianwei Zhao <xianwei.zhao@...ogic.com> wrote:
>
> Hi Bartosz,
>     Could you explain the reproduction method for this problem ?
>

Please don't top-post on the mailing list.

If you have a pin shared by multiple devices in device-tree, it will
now go through a dedicated gpio-shared-proxy driver. It will use a
locking mechanism depending on the can_sleep flag of the GPIO
controller device - spinlock or mutex. If the flag is wrong - like is
the case here - it may happen that we take a spinlock and then descend
into pinctrl where a mutex is taken resulting in a lockdep splat.

Bart