linux-kernel - RE: [PATCH] iio: xilinx-ams: Unmask interrupts after updating alarms

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Message-ID:
 <IA1PR12MB77367112004CB445B805E2B59F33A@IA1PR12MB7736.namprd12.prod.outlook.com>
Date: Wed, 20 Aug 2025 11:23:02 +0000
From: "Erim, Salih" <Salih.Erim@....com>
To: Sean Anderson <sean.anderson@...ux.dev>, Jonathan Cameron
	<jic23@...nel.org>, "linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
	"O'Griofa, Conall" <conall.ogriofa@....com>
CC: David Lechner <dlechner@...libre.com>, Nuno Sá
	<nuno.sa@...log.com>, "linux-arm-kernel@...ts.infradead.org"
	<linux-arm-kernel@...ts.infradead.org>, "Simek, Michal"
	<michal.simek@....com>, Andy Shevchenko <andy@...nel.org>, Manish Narani
	<manish.narani@...inx.com>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] iio: xilinx-ams: Unmask interrupts after updating alarms

Hi Sean,

> -----Original Message-----
> From: Sean Anderson <sean.anderson@...ux.dev>
> Sent: Tuesday, July 15, 2025 1:29 AM
> To: Anand Ashok Dumbre <anand.ashok.dumbre@...inx.com>; Jonathan Cameron
> <jic23@...nel.org>; linux-iio@...r.kernel.org
> Cc: David Lechner <dlechner@...libre.com>; Nuno Sá <nuno.sa@...log.com>;
> linux-arm-kernel@...ts.infradead.org; Simek, Michal <michal.simek@....com>;
> Andy Shevchenko <andy@...nel.org>; Manish Narani
> <manish.narani@...inx.com>; linux-kernel@...r.kernel.org; Sean Anderson
> <sean.anderson@...ux.dev>
> Subject: [PATCH] iio: xilinx-ams: Unmask interrupts after updating alarms
> 
> Caution: This message originated from an External Source. Use proper caution
> when opening attachments, clicking links, or responding.
> 
> 
> To convert level-triggered alarms into edge-triggered IIO events, alarms are masked
> when they are triggered. To ensure we catch subsequent alarms, we then
> periodically poll to see if the alarm is still active.
> If it isn't, we unmask it. Active but masked alarms are stored in
> current_masked_alarm.
> 
> If an active alarm is disabled, it will remain set in current_masked_alarm until
> ams_unmask_worker clears it. If the alarm is re-enabled before
> ams_unmask_worker runs, then it will never be cleared from
> current_masked_alarm. This will prevent the alarm event from being pushed even if
> the alarm is still active.
> 
> Fix this by recalculating current_masked_alarm immediately when enabling or
> disabling alarms.
> 
> Fixes: d5c70627a794 ("iio: adc: Add Xilinx AMS driver")
> Signed-off-by: Sean Anderson <sean.anderson@...ux.dev>
> ---
> 
>  drivers/iio/adc/xilinx-ams.c | 45 ++++++++++++++++++++----------------
>  1 file changed, 25 insertions(+), 20 deletions(-)
> 
> diff --git a/drivers/iio/adc/xilinx-ams.c b/drivers/iio/adc/xilinx-ams.c index
> 76dd0343f5f7..180d4140993d 100644
> --- a/drivers/iio/adc/xilinx-ams.c
> +++ b/drivers/iio/adc/xilinx-ams.c
> @@ -389,6 +389,29 @@ static void ams_update_pl_alarm(struct ams *ams,
> unsigned long alarm_mask)
>         ams_pl_update_reg(ams, AMS_REG_CONFIG3,
> AMS_REGCFG3_ALARM_MASK, cfg);  }
> 
> +static void ams_unmask(struct ams *ams) {
> +       unsigned int status, unmask;
> +
> +       status = readl(ams->base + AMS_ISR_0);
> +
> +       /* Clear those bits which are not active anymore */
> +       unmask = (ams->current_masked_alarm ^ status) &
> + ams->current_masked_alarm;
> +
> +       /* Clear status of disabled alarm */
> +       unmask |= ams->intr_mask;
> +
> +       ams->current_masked_alarm &= status;
> +
> +       /* Also clear those which are masked out anyway */
> +       ams->current_masked_alarm &= ~ams->intr_mask;
> +
> +       /* Clear the interrupts before we unmask them */
> +       writel(unmask, ams->base + AMS_ISR_0);
> +
> +       ams_update_intrmask(ams, ~AMS_ALARM_MASK, ~AMS_ALARM_MASK);
> }
> +
>  static void ams_update_alarm(struct ams *ams, unsigned long alarm_mask)  {
>         unsigned long flags;
> @@ -401,6 +424,7 @@ static void ams_update_alarm(struct ams *ams, unsigned
> long alarm_mask)
> 
>         spin_lock_irqsave(&ams->intr_lock, flags);
>         ams_update_intrmask(ams, AMS_ISR0_ALARM_MASK, ~alarm_mask);
> +       ams_unmask(ams);
>         spin_unlock_irqrestore(&ams->intr_lock, flags);  }
> 
> @@ -1035,28 +1059,9 @@ static void ams_handle_events(struct iio_dev
> *indio_dev, unsigned long events)  static void ams_unmask_worker(struct
> work_struct *work)  {
>         struct ams *ams = container_of(work, struct ams, ams_unmask_work.work);
> -       unsigned int status, unmask;
> 
>         spin_lock_irq(&ams->intr_lock);
> -
> -       status = readl(ams->base + AMS_ISR_0);
> -
> -       /* Clear those bits which are not active anymore */
> -       unmask = (ams->current_masked_alarm ^ status) & ams-
> >current_masked_alarm;
> -
> -       /* Clear status of disabled alarm */
> -       unmask |= ams->intr_mask;
> -
> -       ams->current_masked_alarm &= status;
> -
> -       /* Also clear those which are masked out anyway */
> -       ams->current_masked_alarm &= ~ams->intr_mask;
> -
> -       /* Clear the interrupts before we unmask them */
> -       writel(unmask, ams->base + AMS_ISR_0);
> -
> -       ams_update_intrmask(ams, ~AMS_ALARM_MASK, ~AMS_ALARM_MASK);
> -
> +       ams_unmask(ams);
>         spin_unlock_irq(&ams->intr_lock);
> 
>         /* If still pending some alarm re-trigger the timer */
> --
> 2.35.1.1320.gc452695387.dirty
> 

Tested-by: Erim, Salih <Salih.Erim@....com>
Acked-by: Erim, Salih <Salih.Erim@....com>