On 04/01/2015 08:15 AM, Lars-Peter Clausen wrote:
On 04/01/2015 05:02 PM, Daniel Baluta wrote:
On Wed, Apr 1, 2015 at 5:39 PM, Lars-Peter Clausen <lars@xxxxxxxxxx>
wrote:
On 04/01/2015 04:04 PM, Daniel Baluta wrote:
[...]
+static const struct iio_chan_spec_ext_info ltr501_ext_info[] = {
+ {
+ .name = "intr_persist",
+ .read = ltr501_read_intr_prst,
+ .write = ltr501_write_intr_prst,
+ .shared = IIO_SHARED_BY_TYPE,
+ },
+ {},
+};
+
Would be nice to standardize persistence attribute
(IIO_CHAN_INFO_PERSISTENCE).
If I understand the behavior correctly it causes that the event
needs to be
triggered at least n times before the event is reported by the chip.
In my
opinion 'persistence' is not a good term for that. I'm not sure what a
better term is but I think it should go more in the direction of
ratelimit
or something.
I've seen this term used for many devices:
* TSL25911 ambient light sensor [1]
[ One set of thresholds can be configured to trigger an interrupt
only when
the ambient light exceeds them for a configurable amount of time
(persistence)
]
* TAOS TCS34725 ambient light sensor [2]
[
The interrupt persistence filter allows the user to define the number
of consecutive
out-of-threshold events necessary before generating an interrupt.
]
* Avago SAPDS-9950, Sensortek STK3310
I think the TSL25911 datasheet best describes this parameter, as the
amount of time
that ambient light should exceed a threshold until an interrupt is
generated.
Ok, that makes more sense. I misunderstood the initial description as
that the signal would have to go first above the threshold then below
the threshold, and this for a number of times. Whereas it needs to
exceed the threshold for a certain amount of time before the event is
triggered. If it goes below the threshold before the persistence
interval no event is triggered and the counter is reset.
Yes, it needs to cross the threshold n number of times before a event is
generated.
--
Sathyanarayanan Kuppuswamy
Android kernel developer
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