On 06/04/2014 10:35 AM, Peter Meerwald wrote:
Hello Lars-Peter,
thank you for reviewing this series! reply below
previously, events were always reported as enabled, but actually only
implicitly enabled when updating the buffer scan mode
Signed-off-by: Peter Meerwald <pmeerw@xxxxxxxxxx>
---
drivers/iio/adc/ad799x.c | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 insertions(+)
diff --git a/drivers/iio/adc/ad799x.c b/drivers/iio/adc/ad799x.c
index b8191f1..f8bfbcb 100644
--- a/drivers/iio/adc/ad799x.c
+++ b/drivers/iio/adc/ad799x.c
@@ -375,6 +375,39 @@ static int ad799x_read_event_config(struct iio_dev
*indio_dev,
return 0;
}
+static int ad799x_write_event_config(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ enum iio_event_type type,
+ enum iio_event_direction dir,
+ int state)
+{
+ struct ad799x_state *st = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&indio_dev->mlock);
+ if (iio_buffer_enabled(indio_dev)) {
+ ret = -EBUSY;
+ goto done;
+ }
+
+ if (state)
+ st->config |= BIT(chan->scan_index) << AD799X_CHANNEL_SHIFT;
+ else
+ st->config &= ~(BIT(chan->scan_index) <<
AD799X_CHANNEL_SHIFT);
+
+ if (st->config >> AD799X_CHANNEL_SHIFT)
+ st->config |= AD7998_ALERT_EN;
+ else
+ st->config &= ~AD7998_ALERT_EN;
+
+ ret = ad799x_write_config(st, st->config);
If I understand this correctly the enabled channels will be overwritten again
as soon as the scan mode is updated. I think that is a bit unexpected. I'm not
quite sure how to implement being able to independently enable a channel for
sampling and for event monitoring in a proper way though.
yes, this is a problem; I have no good solution
at least the enabled events show their correct status now :)
one could turn on the union set of event and scan mode channels and ignore
events or measurement when not in the event or or scan mode set, resp.
I that would be better, although it will probably require a custom demux for
the read data.
sysfs-bus-iio documentation says
"So if you want to be sure you have set what you think you have, check the
contents of these attributes after everything is configured. Drivers
may have to buffer any parameters so that they are consistent
when a given event type is enabled at a future point (and not
those for whatever event was previously enabled)."
so there already is a warning :)
another question:
is an event supposed to occur on crossing the threshold or whenever and
as long as the ADC value exceeds the threshold?
the ad7997 does the later, the documentation is not very clear what is
to be expected
It should probably only generate an event when it crosses the threshold
everything else makes little sense since we'd just generate a IRQ storm.
E.g. you can't make a over-temperature event go away in the interrupt
handler. I think in some drivers we temporarily disable the interrupt and
then start polling and wait for the value to go back below the threshold and
then re-enable it.
- Lars
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