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References: <20230420102316.757-1-honda@mechatrax.com> <20230423121528.259d3cd4@jic23-huawei>
In-Reply-To: <20230423121528.259d3cd4@jic23-huawei>
From:   Masahiro Honda <honda@mechatrax.com>
Date:   Wed, 26 Apr 2023 21:02:13 +0900
Message-ID: <CA+Tz-SEAyXcJ++YDzDC=ySd1gOC-j-DDp8sMHBUCSy9Q3wQ4HA@mail.gmail.com>
Subject: Re: [PATCH v3] Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag
To:     Jonathan Cameron <jic23@kernel.org>
Cc:     Lars-Peter Clausen <lars@metafoo.de>,
        Michael Hennerich <Michael.Hennerich@analog.com>,
        linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org
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Hi Jonathan,

On Sun, Apr 23, 2023 at 7:59=E2=80=AFPM Jonathan Cameron <jic23@kernel.org>=
 wrote:
>
> On Thu, 20 Apr 2023 19:23:16 +0900
> Masahiro Honda <honda@mechatrax.com> wrote:
>
> > The Sigma-Delta ADCs supported by this driver can use SDO as an interru=
pt
> > line to indicate the completion of a conversion. However, some devices
> > cannot properly detect the completion of a conversion by an interrupt.
> > This is for the reason mentioned in the following commit.
> >
> > commit e9849777d0e2 ("genirq: Add flag to force mask in
> >                       disable_irq[_nosync]()")
> >
> > A read operation is performed by an extra interrupt before the completi=
on
> > of a conversion. This patch fixes the issue by setting IRQ_DISABLE_UNLA=
ZY
> > flag.
> >
> > Signed-off-by: Masahiro Honda <honda@mechatrax.com>
> > ---
> > v3:
> >  - Remove the Kconfig option.
> > v2: https://lore.kernel.org/linux-iio/20230414102744.150-1-honda@mechat=
rax.com/
> >  - Rework commit message.
> >  - Add a new entry in the Kconfig.
> >  - Call irq_clear_status_flags(irq, IRQ_DISABLE_UNLAZY) when freeing th=
e IRQ.
> > v1: https://lore.kernel.org/linux-iio/20230306044737.862-1-honda@mechat=
rax.com/
> >
> >  drivers/iio/adc/ad_sigma_delta.c | 25 ++++++++++++++++++++-----
> >  1 file changed, 20 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigm=
a_delta.c
> > index d8570f620..215ecbedb 100644
> > --- a/drivers/iio/adc/ad_sigma_delta.c
> > +++ b/drivers/iio/adc/ad_sigma_delta.c
> > @@ -565,6 +565,14 @@ int ad_sd_validate_trigger(struct iio_dev *indio_d=
ev, struct iio_trigger *trig)
> >  }
> >  EXPORT_SYMBOL_NS_GPL(ad_sd_validate_trigger, IIO_AD_SIGMA_DELTA);
> >
> > +static void ad_sd_free_irq(void *sd)
> > +{
> > +     struct ad_sigma_delta *sigma_delta =3D sd;
> > +
> > +     irq_clear_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY)=
;
> > +     free_irq(sigma_delta->spi->irq, sigma_delta);
> > +}
>
> Don't fuse the two operations unwinding like this.  Just register a callb=
ack that only
> does the irq_clear_status_flags immediately after setting them.  Then lea=
ve
> the orginally devm_request_irq call alone.  If it fails, the devm cleanup=
 will
> deal with the irq_clear_status_flag for you.
>
> It almost never makes sense for a single devm call to unwind more than on=
e function call in
> a driver.
>
> Otherwise this looks fine to me,
>
> Thanks,
>
> Jonathan
>

I understand. I'll fix it.

Thanks,