linux-kernel - Re: [PATCH] gpio: rockchip: mark the GPIO controller as sleeping

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Message-ID: <CAMRc=Mf0tRxRrh7tn5OaDn3a47N_qvUcjO=zqbTi-GhY-Y9hOg@mail.gmail.com>
Date: Mon, 12 Jan 2026 10:08:25 +0100
From: Bartosz Golaszewski <brgl@...nel.org>
To: Sebastian Reichel <sebastian.reichel@...labora.com>
Cc: Bartosz Golaszewski <bartosz.golaszewski@....qualcomm.com>, Linus Walleij <linusw@...nel.org>, 
	Heiko Stuebner <heiko@...ech.de>, linux-gpio@...r.kernel.org, 
	linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, stable@...r.kernel.org, 
	Marek Szyprowski <m.szyprowski@...sung.com>
Subject: Re: [PATCH] gpio: rockchip: mark the GPIO controller as sleeping

On Sat, Jan 10, 2026 at 12:55 AM Sebastian Reichel
<sebastian.reichel@...labora.com> wrote:
>
> Hi,
>
> On Tue, Jan 06, 2026 at 10:00:11AM +0100, Bartosz Golaszewski wrote:
> > The GPIO controller is configured as non-sleeping but it uses generic
> > pinctrl helpers which use a mutex for synchronization.
> >
> > This can cause the following lockdep splat with shared GPIOs enabled on
> > boards which have multiple devices using the same GPIO:
> >

[snip]

> >
> > Fixes: 936ee2675eee ("gpio/rockchip: add driver for rockchip gpio")
> > Cc: stable@...r.kernel.org
> > Reported-by: Marek Szyprowski <m.szyprowski@...sung.com>
> > Closes: https://lore.kernel.org/all/d035fc29-3b03-4cd6-b8ec-001f93540bc6@samsung.com/
> > Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@....qualcomm.com>
> > ---
> >  drivers/gpio/gpio-rockchip.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/drivers/gpio/gpio-rockchip.c b/drivers/gpio/gpio-rockchip.c
> > index 47174eb3ba76..bae2061f15fc 100644
> > --- a/drivers/gpio/gpio-rockchip.c
> > +++ b/drivers/gpio/gpio-rockchip.c
> > @@ -593,6 +593,7 @@ static int rockchip_gpiolib_register(struct rockchip_pin_bank *bank)
> >       gc->ngpio = bank->nr_pins;
> >       gc->label = bank->name;
> >       gc->parent = bank->dev;
> > +     gc->can_sleep = true;
>
> This means all operations are marked as can_sleep, even though
> pinctrl operations are only used for the direction setting.
> I.e. the common get/set operations always worked in atomic mode,
> but now complain. See for example:
>
> https://lore.kernel.org/all/20260108-media-synopsys-hdmirx-fix-gpio-cansleep-v1-1-3570518d8bab@kernel.org/
>
> It's not a big issue for the hdmirx driver specifically, but I wonder
> how many more (less often tested) rockchip drivers use GPIOs from their
> IRQ handler.
>
> Considering setting or getting the GPIO from atomic context is much
> more common than changing the direction - is there some way to
> describe the sleep behavior in a more specific way in the GPIO
> controller?
>

No, there's no such switch at the moment. This is because there are
paths that we can take, where we *do* end up setting direction from
gpiod_set_value(). For instance:

gpiod_set_value()
  gpiod_set_value_nocheck()
    gpio_set_open_drain_value_commit()
      gpiochip_direction_output()

I'm afraid, for correctness, it has to be either sleeping, or not. I
would love - at some point - to make pinctrl mostly lockless with
SRCU, like we did with GPIO. That would solve this issue correctly.
But until then, I'm afraid we need to keep a chip-global switch for
sleeping.

Bartosz