Added rate control support for ALS and proximity
threshold interrupts.Also, Added support to modify
and read ALS & proximity sensor sampling frequency.
LTR-501 supports interrupt rate control using persistence
register settings. Writing <n> to persistence register
would generate interrupt only if there are <n> consecutive
data values outside the threshold range.
Since we don't have any existing ABI's to directly
control the persistence register count, we have implemented
the rate control using IIO_EV_INFO_PERIOD. _period event
attribute represents the amount of time in seconds an
event should be true for the device to generate the
interrupt. So using _period value and device frequency,
persistence count is calculated in driver using following
logic.
count = period / measurement_rate
If the given period is not a multiple of measurement rate then
we round up the value to next multiple.
This patch also handles change to persistence count whenever
there is change in frequency.
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
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