On Thu, 20 Apr 2023 19:23:16 +0900
Masahiro Honda <honda@xxxxxxxxxxxxx> 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 <honda@xxxxxxxxxxxxx>
> ---
> v3:
> - Remove the Kconfig option.
> v2: https://lore.kernel.org/linux-iio/20230414102744.150-1-honda@xxxxxxxxxxxxx/
> - 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@xxxxxxxxxxxxx/
>
> 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_sigma_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_dev, 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 = 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 callback that only
does the irq_clear_status_flags immediately after setting them. Then leave
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 one function call in
a driver.
Otherwise this looks fine to me,
Thanks,
Jonathan
> +
> static int devm_ad_sd_probe_trigger(struct device *dev, struct iio_dev *indio_dev)
> {
> struct ad_sigma_delta *sigma_delta = iio_device_get_drvdata(indio_dev);
> @@ -584,11 +592,18 @@ 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;
> - ret = devm_request_irq(dev, sigma_delta->spi->irq,
> - ad_sd_data_rdy_trig_poll,
> - sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,
> - indio_dev->name,
> - sigma_delta);
> + irq_set_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY);
> + ret = request_irq(sigma_delta->spi->irq,
> + ad_sd_data_rdy_trig_poll,
> + sigma_delta->info->irq_flags | IRQF_NO_AUTOEN,
> + indio_dev->name,
> + sigma_delta);
> + if (ret) {
> + irq_clear_status_flags(sigma_delta->spi->irq, IRQ_DISABLE_UNLAZY);
> + return ret;
> + }
> +
> + ret = devm_add_action_or_reset(dev, ad_sd_free_irq, sigma_delta);
> if (ret)
> return ret;
>
