Re: [PATCH v2 2/6] iio: light: stk3310: Implement vdd supply and power it off during suspend

From: Andy Shevchenko <andy.shevchenko@gmail.com>
To: "Ondřej 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>,
	"Uwe Kleine-König" <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>
Subject: Re: [PATCH v2 2/6] iio: light: stk3310: Implement vdd supply and power it off during suspend
Date: Wed, 24 Apr 2024 18:20:41 +0300	[thread overview]
Message-ID: <CAHp75VdR9HtWbSif+j8QHX5zG9xPF1GzUFY2s-0OjD3RAWD9-Q@mail.gmail.com> (raw)
In-Reply-To: <5qqil7ltqhdeabml6toqpcy773uhjxgwaz3txpy4kv4sz55o2y@hmar674eey7s>

On Wed, Apr 24, 2024 at 3:59 PM Ondřej Jirman <megi@xff.cz> wrote:
> On Wed, Apr 24, 2024 at 02:16:06AM GMT, Andy Shevchenko wrote:
> > On Wed, Apr 24, 2024 at 1:41 AM Aren Moynihan <aren@peacevolution.org> wrote:

...

> > >         ret = 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.

-- 
With Best Regards,
Andy Shevchenko