Re: [PATCH v5] iio: adc: ad_sigma_delta: Fix IRQ issue by setting IRQ_DISABLE_UNLAZY flag

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 18 May 2023 20:08:16 +0900
Masahiro Honda <honda@mechatrax.com> 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. At this time, the value read from the ADC data register
> is the same as the previous conversion result. This patch fixes the issue
> by setting IRQ_DISABLE_UNLAZY flag.
> 
> Fixes: 0c6ef985a1f ("iio: adc: ad7791: fix IRQ flags")
> Fixes: 1a913270e57 ("iio: adc: ad7793: Fix IRQ flag")
> Fixes: e081102f307 ("iio: adc: ad7780: Fix IRQ flag")
> Fixes: 89a86da5cb8 ("iio: adc: ad7192: Add IRQ flag")
> Fixes: 79ef91493f5 ("iio: adc: ad7124: Set IRQ type to falling")
All the fixes tags have 11 chars of the hash, needs to be 12. I fixed that up whilst applying

Applied to the fixes-togreg branch of iio.git and marked for stable.

Thanks,

Jonathan

> Signed-off-by: Masahiro Honda <honda@mechatrax.com>
> ---
> v5:
>  - Fix the patch title.
>  - Add fixes tags.
>  - Add information about behavior to the commit message.
> v4: https://lore.kernel.org/linux-iio/20230502102930.773-1-honda@mechatrax.com/
>  - Remove the callback.
> v3: https://lore.kernel.org/linux-iio/20230420102316.757-1-honda@mechatrax.com/
>  - Remove the Kconfig option.
> v2: https://lore.kernel.org/linux-iio/20230414102744.150-1-honda@mechatrax.com/
>  - 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/20230306044737.862-1-honda@mechatrax.com/
> 
>  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 d8570f62078..7e219287074 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,