On Thu, 22 Jun 2023 08:53:41 +0200
Leonard Göhrs <l.goehrs@xxxxxxxxxxxxxx> wrote:
> Enable buffered reading of samples from the LMP92064 ADC.
> The main benefit of this change is being able to read out current and
> voltage measurements in a single transfer, allowing instantaneous power
> measurements.
>
> Reads into the buffer can be triggered by any software triggers, e.g.
> the iio-trig-hrtimer:
>
> $ mkdir /sys/kernel/config/iio/triggers/hrtimer/my-trigger
> $ cat /sys/bus/iio/devices/iio\:device3/name
> lmp92064
> $ iio_readdev -t my-trigger -b 16 iio:device3 | hexdump
> WARNING: High-speed mode not enabled
> 0000000 0000 0176 0101 0001 5507 abd5 7645 1768
> 0000010 0000 016d 0101 0001 ee1e ac6b 7645 1768
> ...
>
> Signed-off-by: Leonard Göhrs <l.goehrs@xxxxxxxxxxxxxx>
A minor follow up comment inline.
> static int lmp92064_read_meas(struct lmp92064_adc_priv *priv, u16 *res)
> @@ -171,6 +192,29 @@ static int lmp92064_read_raw(struct iio_dev *indio_dev,
> }
> }
>
> +static irqreturn_t lmp92064_trigger_handler(int irq, void *p)
> +{
> + struct iio_poll_func *pf = p;
> + struct iio_dev *indio_dev = pf->indio_dev;
> + struct lmp92064_adc_priv *priv = iio_priv(indio_dev);
> + struct {
> + u16 values[2];
> + int64_t timestamp;
> + } data;
> + int ret;
> +
> + ret = lmp92064_read_meas(priv, data.values);
> + if (ret >= 0) {
Even thought it's more code, in IIO at least we tend to prefer to handle
errors out of line
if (ret)
goto err;
iio_push_to_buffers....
err:
iio_trigger_notify_done()
return IRQ_HANDLED;
Also, read_meas doesn't return > 0 which is implied by the above check.
> + /* Only push values if the read succeeded */
> + iio_push_to_buffers_with_timestamp(indio_dev, &data,
> + iio_get_time_ns(indio_dev));
> + }
> +
> + iio_trigger_notify_done(indio_dev->trig);
> +
> + return IRQ_HANDLED;
> +}
> +
