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From: Andy Shevchenko <andy.shevchenko@gmail.com>
Date: Wed, 24 Apr 2024 18:20:41 +0300
Message-ID: <CAHp75VdR9HtWbSif+j8QHX5zG9xPF1GzUFY2s-0OjD3RAWD9-Q@mail.gmail.com>
Subject: Re: [PATCH v2 2/6] iio: light: stk3310: Implement vdd supply and
 power it off during suspend
To: =?UTF-8?Q?Ond=C5=99ej_Jirman?= <megi@xff.cz>, 
	Andy Shevchenko <andy.shevchenko@gmail.com>, Aren Moynihan <aren@peacevolution.org>, 
	Jonathan Cameron <jic23@kernel.org>, Lars-Peter Clausen <lars@metafoo.de>, Rob Herring <robh@kernel.org>, 
	Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>, Conor Dooley <conor+dt@kernel.org>, 
	Chen-Yu Tsai <wens@csie.org>, Jernej Skrabec <jernej.skrabec@gmail.com>, 
	Samuel Holland <samuel@sholland.org>, Liam Girdwood <lgirdwood@gmail.com>, 
	Mark Brown <broonie@kernel.org>, =?UTF-8?Q?Uwe_Kleine=2DK=C3=B6nig?= <u.kleine-koenig@pengutronix.de>, 
	linux-iio@vger.kernel.org, phone-devel@vger.kernel.org, 
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, 
	linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, 
	Willow Barraco <contact@willowbarraco.fr>
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On Wed, Apr 24, 2024 at 3:59=E2=80=AFPM Ond=C5=99ej Jirman <megi@xff.cz> wr=
ote:
> On Wed, Apr 24, 2024 at 02:16:06AM GMT, Andy Shevchenko wrote:
> > On Wed, Apr 24, 2024 at 1:41=E2=80=AFAM Aren Moynihan <aren@peacevoluti=
on.org> wrote:

..

> > >         ret =3D stk3310_init(indio_dev);
> > >         if (ret < 0)
> > > -               return ret;
> > > +               goto err_vdd_disable;
> >
> > This is wrong. You will have the regulator being disabled _before_
> > IRQ. Note, that the original code likely has a bug which sets states
> > before disabling IRQ and removing a handler.
>
> How so? stk3310_init is called before enabling the interrupt.

Exactly, IRQ is registered with devm and hence the error path and
remove stages will got it in a wrong order.

> Original code has a bug that IRQ is enabled before registering the
> IIO device,

Indeed, but this is another bug.

> so if IRQ is triggered before registration, iio_push_event
> from IRQ handler may be called on a not yet registered IIO device.
>
> Never saw it happen, though. :)

Because nobody cares enough to enable DEBUG_SHIRQ.

--=20
With Best Regards,
Andy Shevchenko