Re: [PATCH v6 2/2] iio: light: ROHM BH1745 colour sensor

Mudit Sharma
2024-06-29T09:10:28Z

On 28/06/2024 20:37, Jonathan Cameron wrote:
> Hi Mudit,
>
> I'd failed on previous reviews to notice the odd trigger in here.
> What is it, because it doesn't seem to be a dataready trigger as the device
> doesn't seem to provide such an interrupt?

Hi Jonathan,

Thank you for your review on this.

I've incorrect called it as a dataready trigger, I missed this as part
of my initial cleanup - apologies for the confusion caused by this. I
should potentially call it 'threshold' or 'dev'. Please suggest what you
think would be appropriate here.

The sensor has an active low interrupt pin which is connected to a GPIO
(input, pullup). When the sensor reading crosses value set in threshold
high or threshold low resisters, interrupt signal is generated and the
interrupt gets handled in 'bh1745_interrupt_handler()' (interrupt also
depends on number of consecutive judgements set in BH1745_PERSISTENCE
register)

>
> Various other comments inline.

Will address all for v7
>
...
>> +static irqreturn_t bh1745_interrupt_handler(int interrupt, void *p)
>> +{
>> + struct iio_dev *indio_dev = p;
>> + struct bh1745_data *data = iio_priv(indio_dev);
>> + int ret;
>> + int value;
>> +
>> + ret = regmap_read(data->regmap, BH1745_INTR, &value);
>> + if (ret)
>> + return IRQ_NONE;
>> +
>> + if (value & BH1745_INTR_STATUS) {
>> + guard(mutex)(&data->lock);
>> + iio_push_event(indio_dev,
>> + IIO_UNMOD_EVENT_CODE(IIO_INTENSITY, data->int_src,
>> + IIO_EV_TYPE_THRESH,
>> + IIO_EV_DIR_EITHER),
>> + iio_get_time_ns(indio_dev));
>
> What is happening here. You always push out the event and use that as
> a trigger? This is an unusual trigger if it's appropriate to use it for
> one at all. You've called it a dataready trigger but it is not obvious
> that this device provides any such signal.

When an interrupt occurs, BH1745_INTR_STATUS bit is set in the
BH1745_INTR register. Event is only pushed out when the
BH1745_INTR_STATUS bit is set.
>> +
>> + iio_trigger_poll_nested(data->trig);
>> +
>> + return IRQ_HANDLED;
>> + }
>> +
>> + return IRQ_NONE;
>> +}

Best regards,
Mudit Sharma