Re: [PATCH] iio: xilinx-ams: Unmask interrupts after updating alarms

On Wed, 20 Aug 2025 11:28:27 +0000
"O'Griofa, Conall" [off-list ref] wrote:

Hi,

Looks good, thank you for taking the time to submit this patch.

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

Thanks,

Jonathan

Cheers,
Conall.

quoted

-----Original Message-----
From: Sean Anderson <sean.anderson@linux.dev>
Sent: 15 July 2025 01:29
To: Anand Ashok Dumbre <redacted>; Jonathan Cameron
[off-list ref]; linux-iio@vger.kernel.org
Cc: David Lechner <dlechner@baylibre.com>; Nuno Sá <nuno.sa@analog.com>;
linux-arm-kernel@lists.infradead.org; Simek, Michal [off-list ref];
Andy Shevchenko [off-list ref]; Manish Narani
[off-list ref]; linux-kernel@vger.kernel.org; Sean Anderson
[off-list ref]
Subject: [PATCH] iio: xilinx-ams: Unmask interrupts after updating alarms

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@linux.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-  

quoted

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  

Reviewed-by: O'Griofa, Conall <conall.ogriofa@amd.com>