Re: [PATCH 2/2] iio: invensense: improve period measurement by using a longer delay

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Fri, Jul 17, 2026 at 02:39:41PM +0200, Jean-Baptiste Maneyrol via B4 Relay wrote:

> Period measurement can be difficult when using high sampling
> frequency where the jitter criteria is hard to meet because of the
> system jitter.
> 
> This new version is using the delta time between 2 distant interrupts
> to measure an interval of at least 20ms. 20ms is a good compromise
> between the mitigation of system jitter and the delay to update
> period. This way we decorrelate the period measurement from the
> interrupt timestamps syncing using only the 2 last interrupts.

...

>  void inv_sensors_timestamp_interrupt(struct inv_sensors_timestamp *ts,
>  				     size_t sample_nb, int64_t timestamp)
>  {
> +	const int64_t delta_threshold =
> +			INV_SENSORS_TIMESTAMP_MIN(INV_SENSORS_MIN_IT_DELTA,
> +						  ts->chip.jitter);

This is less readable than the split version.

	const s64 delta_threshold;

Also, what const gives us here?

>  	struct inv_sensors_timestamp_interval *it;
>  	int64_t delta, interval;
>  	uint32_t period;
> -	bool valid = false;
> +	bool valid;

	delta_threshold =
		INV_SENSORS_TIMESTAMP_MIN(INV_SENSORS_MIN_IT_DELTA, ts->chip.jitter);

(yes, I would go for a bit longer line).


>  	if (sample_nb == 0)
>  		return;

And why to assign it if we have to return, for example here?
Move the assignment closer to its first user.

-- 
With Best Regards,
Andy Shevchenko