Re: [PATCH 4/6] iio: chemical: ens160: add triggered buffer support

[Christophe JAILLET]

Le 19/05/2024 à 16:03, Jonathan Cameron a écrit :
> On Mon, 13 May 2024 21:13:07 +0200
> Christophe JAILLET <christophe.jaillet-39ZsbGIQGT5GWvitb5QawA@xxxxxxxxxxxxxxxx> wrote:
>
> > Le 12/05/2024 à 23:04, Gustavo Silva a écrit :
> > > ENS160 supports a data ready interrupt. Use it in combination with
> > > triggered buffer for continuous data readings.
> > >
> > > Signed-off-by: Gustavo Silva <gustavograzs-Re5JQEeQqe8AvxtiuMwx3w@xxxxxxxxxxxxxxxx>
> > > ---
> >
> > ...
> >
> > > +static irqreturn_t ens160_trigger_handler(int irq, void *p)
> > > +{
> > > +	struct iio_poll_func *pf = p;
> > > +	struct iio_dev *indio_dev = pf->indio_dev;
> > > +	struct ens160_data *data = iio_priv(indio_dev);
> > > +	__le16 val;
> > > +	int ret, i, j = 0;
> > > +
> > > +	mutex_lock(&data->mutex);
> > > +
> > > +	for_each_set_bit(i, indio_dev->active_scan_mask,
> > > +			 indio_dev->masklength) {
> > > +		ret = regmap_bulk_read(data->regmap,
> > > +				       ENS160_REG_DATA_TVOC + 2 * i, &val, 2U);
> > > +		if (ret)
> > > +			goto err;
> > > +
> > > +		data->scan.chans[j++] = val;
> >
> > Is it safe? How can we know if it has been only *partly* updated? Does
> > it matter to know?
>
> You've lost me. What do you mean by partly updated?
> This won't push anything to the kfifo etc unless all succeeded.
> Or is there a race with something else in here?

Forget it, I misread the place of iio_push_to_buffers_with_timestamp().

I thought we were going through it when 'goto err'.

CJ

> > CJ
> >
> > > +	}
> > > +
> > > +	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
> > > +					   pf->timestamp);
> > > +err:
> > > +	mutex_unlock(&data->mutex);
> > > +	iio_trigger_notify_done(indio_dev->trig);
> > > +
> > > +	return IRQ_HANDLED;
> > > +}
> >
> > ...