Re: [PATCH v3 2/5] iio: light: vcnl4000: clear DRDY interrupt when buffer disabled

[Jonathan Cameron <jic23@kernel.org>]

On Thu, 03 Sep 2026 14:53:47 +1000
Tsz Shan Chan <tsz.chan.dev@gmail.com> wrote:

> on vcnl4010/4020, interrupt status bits are cleared by writing 1 to the
> corresponding bit in the ISR register. If data ready interrupt triggers
> when the iio buffer is disabled, the DRDY bit is never cleared and the
> interrupt line stays low.
> 
> Clear the DRDY bit in the interrupt handler when the buffer is disabled.

Add something on why we might actually see this. Are we looking at a race
condition or normal operation?  I.e. does this happen on sysfs reads?
I think it is just the race condition around the buffer going down
but good to have that called out in this description if that is
correct.

Thanks,

Jonathan


> 
> Signed-off-by: Tsz Shan Chan <tchan@jacques.com.au>
> ---
>  drivers/iio/light/vcnl4000.c | 9 +++++++--
>  1 file changed, 7 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> index cf55fe6afcba..c5f34e748e1a 100644
> --- a/drivers/iio/light/vcnl4000.c
> +++ b/drivers/iio/light/vcnl4000.c
> @@ -1545,8 +1545,13 @@ static irqreturn_t vcnl4010_irq_thread(int irq, void *p)
>  					  isr & VCNL4010_INT_THR);
>  	}
>  
> -	if (isr & VCNL4010_INT_DRDY && iio_buffer_enabled(indio_dev))
> -		iio_trigger_poll_nested(indio_dev->trig);
> +	if ((isr & VCNL4010_INT_DRDY)) {
> +		if (iio_buffer_enabled(indio_dev))
> +			iio_trigger_poll_nested(indio_dev->trig);
> +		else
> +			i2c_smbus_write_byte_data(data->client, VCNL4010_ISR,
> +						  isr & VCNL4010_INT_DRDY);
> +	}
>  
>  end:
>  	return IRQ_HANDLED;
>