2023-05-02 10:36:42

by Masahiro Honda

[permalink] [raw]
Subject: [PATCH v4] Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag

The Sigma-Delta ADCs supported by this driver can use SDO as an interrupt
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 completion
of a conversion. This patch fixes the issue by setting IRQ_DISABLE_UNLAZY
flag.

Signed-off-by: Masahiro Honda <[email protected]>
---
v4:
- Remove the callback.
v3: https://lore.kernel.org/linux-iio/[email protected]/
- Remove the Kconfig option.
v2: https://lore.kernel.org/linux-iio/[email protected]/
- Rework commit message.
- Add a new entry in the Kconfig.
- Call irq_clear_status_flags(irq, IRQ_DISABLE_UNLAZY) when freeing the IRQ.
v1: https://lore.kernel.org/linux-iio/[email protected]/

drivers/iio/adc/ad_sigma_delta.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/iio/adc/ad_sigma_delta.c b/drivers/iio/adc/ad_sigma_delta.c
index d8570f6207..7e21928707 100644
--- a/drivers/iio/adc/ad_sigma_delta.c
+++ b/drivers/iio/adc/ad_sigma_delta.c
@@ -584,6 +584,10 @@ static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_de
init_completion(&sigma_delta->completion);

sigma_delta->irq_dis = true;
+
+ /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */
+ irq_set_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY);
+
ret = devm_request_irq(dev, sigma_delta->spi->irq,
ad_sd_data_rdy_trig_poll,
sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,
--
2.34.1


2023-05-03 08:09:10

by Nuno Sá

[permalink] [raw]
Subject: Re: [PATCH v4] Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag

On Tue, 2023-05-02 at 19:29 +0900, Masahiro Honda wrote:
> The Sigma-Delta ADCs supported by this driver can use SDO as an interrupt
> 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 completion
> of a conversion. This patch fixes the issue by setting IRQ_DISABLE_UNLAZY
> flag.
>
> Signed-off-by: Masahiro Honda <[email protected]>
> ---

Reviewed-by: Nuno Sá <[email protected]>

> v4:
>  - Remove the callback.
> v3:
> https://lore.kernel.org/linux-iio/[email protected]/
>  - Remove the Kconfig option.
> v2:
> https://lore.kernel.org/linux-iio/[email protected]/
>  - Rework commit message.
>  - Add a new entry in the Kconfig.
>  - Call irq_clear_status_flags(irq, IRQ_DISABLE_UNLAZY) when freeing the IRQ.
> v1:
> https://lore.kernel.org/linux-iio/[email protected]/
>
>  drivers/iio/adc/ad_sigma_delta.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/iio/adc/ad_sigma_delta.c
> b/drivers/iio/adc/ad_sigma_delta.c
> index d8570f6207..7e21928707 100644
> --- a/drivers/iio/adc/ad_sigma_delta.c
> +++ b/drivers/iio/adc/ad_sigma_delta.c
> @@ -584,6 +584,10 @@ static int devm_ad_sd_probe_trigger(struct device *dev,
> struct iio_dev *indio_de
>         init_completion(&sigma_delta->completion);
>  
>         sigma_delta->irq_dis = true;
> +
> +       /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */
> +       irq_set_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY);
> +
>         ret = devm_request_irq(dev, sigma_delta->spi->irq,
>                                ad_sd_data_rdy_trig_poll,
>                                sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,

2023-05-07 14:50:14

by Jonathan Cameron

[permalink] [raw]
Subject: Re: [PATCH v4] Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag

On Wed, 03 May 2023 10:09:28 +0200
Nuno Sá <[email protected]> wrote:

Patch title should be something like the following so it's easy to see what
is affected when looking at a long list of patches.

iio: adc: ad_sigma_delta: Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag.


> On Tue, 2023-05-02 at 19:29 +0900, Masahiro Honda wrote:
> > The Sigma-Delta ADCs supported by this driver can use SDO as an interrupt
> > 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 completion
> > of a conversion. This patch fixes the issue by setting IRQ_DISABLE_UNLAZY
> > flag.
> >
> > Signed-off-by: Masahiro Honda <[email protected]>
> > ---
>
> Reviewed-by: Nuno Sá <[email protected]>

Fixes tag? We'll want to know how far to backport this. I assume it's
limited by the above commit as these drivers are older than that.

I'm also not totally sure what this 'looks like' for a user. What happens?
Fail to read, wrong value, lock up or something else? It would be helpful
to include that information in case anyone else runs into this.

Actual change looks right to me.

Thanks,

Jonathan


>
> > v4:
> >  - Remove the callback.
> > v3:
> > https://lore.kernel.org/linux-iio/[email protected]/
> >  - Remove the Kconfig option.
> > v2:
> > https://lore.kernel.org/linux-iio/[email protected]/
> >  - Rework commit message.
> >  - Add a new entry in the Kconfig.
> >  - Call irq_clear_status_flags(irq, IRQ_DISABLE_UNLAZY) when freeing the IRQ.
> > v1:
> > https://lore.kernel.org/linux-iio/[email protected]/
> >
> >  drivers/iio/adc/ad_sigma_delta.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/iio/adc/ad_sigma_delta.c
> > b/drivers/iio/adc/ad_sigma_delta.c
> > index d8570f6207..7e21928707 100644
> > --- a/drivers/iio/adc/ad_sigma_delta.c
> > +++ b/drivers/iio/adc/ad_sigma_delta.c
> > @@ -584,6 +584,10 @@ static int devm_ad_sd_probe_trigger(struct device *dev,
> > struct iio_dev *indio_de
> >         init_completion(&sigma_delta->completion);
> >  
> >         sigma_delta->irq_dis = true;
> > +
> > +       /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */
> > +       irq_set_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY);
> > +
> >         ret = devm_request_irq(dev, sigma_delta->spi->irq,
> >                                ad_sd_data_rdy_trig_poll,
> >                                sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,
>

2023-05-08 11:04:22

by Masahiro Honda

[permalink] [raw]
Subject: Re: [PATCH v4] Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag

Hi Jonathan,

Thank you for your advice.

On Sun, May 7, 2023 at 11:45 PM Jonathan Cameron <[email protected]> wrote:
>
> On Wed, 03 May 2023 10:09:28 +0200
> Nuno Sá <[email protected]> wrote:
>
> Patch title should be something like the following so it's easy to see what
> is affected when looking at a long list of patches.
>
> iio: adc: ad_sigma_delta: Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag.
>

I'll fix the title.

>
> > On Tue, 2023-05-02 at 19:29 +0900, Masahiro Honda wrote:
> > > The Sigma-Delta ADCs supported by this driver can use SDO as an interrupt
> > > 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 completion
> > > of a conversion. This patch fixes the issue by setting IRQ_DISABLE_UNLAZY
> > > flag.
> > >
> > > Signed-off-by: Masahiro Honda <[email protected]>
> > > ---
> >
> > Reviewed-by: Nuno Sá <[email protected]>
>
> Fixes tag? We'll want to know how far to backport this. I assume it's
> limited by the above commit as these drivers are older than that.
>

I'll try to add a fixes tag.

> I'm also not totally sure what this 'looks like' for a user. What happens?
> Fail to read, wrong value, lock up or something else? It would be helpful
> to include that information in case anyone else runs into this.
>

I'll add information to the commit message.

Regards,

Masahiro


> Actual change looks right to me.
>
> Thanks,
>
> Jonathan
>
>
> >
> > > v4:
> > > - Remove the callback.
> > > v3:
> > > https://lore.kernel.org/linux-iio/[email protected]/
> > > - Remove the Kconfig option.
> > > v2:
> > > https://lore.kernel.org/linux-iio/[email protected]/
> > > - Rework commit message.
> > > - Add a new entry in the Kconfig.
> > > - Call irq_clear_status_flags(irq, IRQ_DISABLE_UNLAZY) when freeing the IRQ.
> > > v1:
> > > https://lore.kernel.org/linux-iio/[email protected]/
> > >
> > > drivers/iio/adc/ad_sigma_delta.c | 4 ++++
> > > 1 file changed, 4 insertions(+)
> > >
> > > diff --git a/drivers/iio/adc/ad_sigma_delta.c
> > > b/drivers/iio/adc/ad_sigma_delta.c
> > > index d8570f6207..7e21928707 100644
> > > --- a/drivers/iio/adc/ad_sigma_delta.c
> > > +++ b/drivers/iio/adc/ad_sigma_delta.c
> > > @@ -584,6 +584,10 @@ static int devm_ad_sd_probe_trigger(struct device *dev,
> > > struct iio_dev *indio_de
> > > init_completion(&sigma_delta->completion);
> > >
> > > sigma_delta->irq_dis = true;
> > > +
> > > + /* the IRQ core clears IRQ_DISABLE_UNLAZY flag when freeing an IRQ */
> > > + irq_set_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY);
> > > +
> > > ret = devm_request_irq(dev, sigma_delta->spi->irq,
> > > ad_sd_data_rdy_trig_poll,
> > > sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,
> >
>