On 04/01/2015 10:48 AM, Lars-Peter Clausen wrote:
On 04/01/2015 07:45 PM, sathyanarayanan kuppuswamy wrote:
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.
Wait. It needs to cross the threshold or it needs to stay above the
threshold?
Following is the logic for this chip.
If ( data > Upper_threshold or data < Lower_threshold)
generate_event()
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--
Sathyanarayanan Kuppuswamy
Android kernel developer
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