quad8_irq_handler() should return irqreturn_t enum values, but it
directly returns negative errno codes from regmap operations on error.

Return IRQ_NONE if the interrupt status cannot be read. If clearing the
interrupt fails, return IRQ_HANDLED to prevent the kernel from disabling
the IRQ line due to a spurious interrupt storm. Also, log these regmap
failures with WARN_ONCE.

Fixes: 98ffe0252911 ("counter: 104-quad-8: Migrate to the regmap API")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
---
Changes in v2:
  -Return IRQ_HANDLED if regmap_write() fails.
  -Add WARN_ONCE() to log the error messages.
---
 drivers/counter/104-quad-8.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/counter/104-quad-8.c b/drivers/counter/104-quad-8.c
index ce81fc4e1ae7..836ab9349dd7 100644
--- a/drivers/counter/104-quad-8.c
+++ b/drivers/counter/104-quad-8.c
@@ -1200,8 +1200,10 @@ static irqreturn_t quad8_irq_handler(int irq, void *private)
 	int ret;
 
 	ret = regmap_read(priv->map, QUAD8_INTERRUPT_STATUS, &status);
-	if (ret)
-		return ret;
+	if (ret) {
+		WARN_ONCE(true, "quad8: regmap_read failed: %d\n", ret);
+		return IRQ_NONE;
+	}
 	if (!status)
 		return IRQ_NONE;
 
@@ -1232,8 +1234,10 @@ static irqreturn_t quad8_irq_handler(int irq, void *private)
 	}
 
 	ret = regmap_write(priv->map, QUAD8_CHANNEL_OPERATION, CLEAR_PENDING_INTERRUPTS);
-	if (ret)
-		return ret;
+	if (ret) {
+		WARN_ONCE(true, "quad8: regmap_write failed: %d\n", ret);
+		return IRQ_HANDLED;
+	}
 
 	return IRQ_HANDLED;
 }
-- 
2.50.1.windows.1

On Sun, Dec 07, 2025 at 02:00:07AM +0800, Haotian Zhang wrote:
> quad8_irq_handler() should return irqreturn_t enum values, but it
> directly returns negative errno codes from regmap operations on error.
> 
> Return IRQ_NONE if the interrupt status cannot be read. If clearing the
> interrupt fails, return IRQ_HANDLED to prevent the kernel from disabling
> the IRQ line due to a spurious interrupt storm. Also, log these regmap
> failures with WARN_ONCE.
> 
> Fixes: 98ffe0252911 ("counter: 104-quad-8: Migrate to the regmap API")
> Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
> ---
> Changes in v2:
>   -Return IRQ_HANDLED if regmap_write() fails.
>   -Add WARN_ONCE() to log the error messages.

Hi Haotian,

Thank you for making the requested changes. I have a couple more
suggestions below, and then I think this patch will be ready to merge.

>  	ret = regmap_read(priv->map, QUAD8_INTERRUPT_STATUS, &status);
> -	if (ret)
> -		return ret;
> +	if (ret) {
> +		WARN_ONCE(true, "quad8: regmap_read failed: %d\n", ret);

The warning should indicate the purpose of the operation so users know
what failed for the hardware. So perhaps "quad8: Attempt to read
Interrupt Status Register failed: %d\n" is better.

>  	ret = regmap_write(priv->map, QUAD8_CHANNEL_OPERATION, CLEAR_PENDING_INTERRUPTS);
> -	if (ret)
> -		return ret;
> +	if (ret) {
> +		WARN_ONCE(true, "quad8: regmap_write failed: %d\n", ret);

For the same reason as above, perhaps "quad8: Attempt to clear pending
interrupts by writing to Channel Operation Register failed: %d\n" is
better.

William Breathitt Gray

On Fri, Dec 12, 2025 at 12:34:07PM +0900, William Breathitt Gray wrote:
> On Sun, Dec 07, 2025 at 02:00:07AM +0800, Haotian Zhang wrote:

...

> >  	ret = regmap_read(priv->map, QUAD8_INTERRUPT_STATUS, &status);
> > -	if (ret)
> > -		return ret;
> > +	if (ret) {
> > +		WARN_ONCE(true, "quad8: regmap_read failed: %d\n", ret);
> 
> The warning should indicate the purpose of the operation so users know
> what failed for the hardware. So perhaps "quad8: Attempt to read
> Interrupt Status Register failed: %d\n" is better.
> 
> >  	ret = regmap_write(priv->map, QUAD8_CHANNEL_OPERATION, CLEAR_PENDING_INTERRUPTS);
> > -	if (ret)
> > -		return ret;
> > +	if (ret) {
> > +		WARN_ONCE(true, "quad8: regmap_write failed: %d\n", ret);
> 
> For the same reason as above, perhaps "quad8: Attempt to clear pending
> interrupts by writing to Channel Operation Register failed: %d\n" is
> better.

On top of that, I'm wondering if we can use dev_WARN_ONCE() and drop "quad8: "
prefix.

-- 
With Best Regards,
Andy Shevchenko