Re: [PATCH v4] iio: tcs3472: implement wait time and sampling frequency

On Tue, Jun 09, 2026 at 03:36:03PM +0200, Aldo Conte wrote:
> On 09/06/26 14:15, Andy Shevchenko wrote:
> > On Tue, Jun 09, 2026 at 12:27:52PM +0200, Aldo Conte wrote:

...

> > > case IIO_EV_INFO_PERIOD:
> > > 		period = tcs3472_cycle_time_us(data) *
> > > 			tcs3472_intr_pers[data->apers];
> > > 		*val = period / USEC_PER_SEC;
> > > 		*val2 = period % USEC_PER_SEC;
> > 
> > Again, use HZ-based multiplier, see above.
> 
> Here i do not understand why MICROHZ_PER_HZ is better.
> In the previous case, we were indeed referring to the denominator of the
> calculation, which was actually a frequency, so MICROHZ_PER_HZ is indeed
> correct.
> But in this case, we are calculating the integer and fractional parts of a
> period, so I think this would be fine.
> Tell me where I’m going wrong.

Hmm... I think you are right and I stand corrected.

> > > 		return IIO_VAL_INT_PLUS_MICRO;
> > > 
> > > write becomes:
> > > 
> > > case IIO_EV_INFO_PERIOD:{
> > > 		unsigned int cycle_us;
> > > 
> > > 		period = val * USEC_PER_SEC + val2;
> > 
> > And again, use HZ-based multiplier, see above.
> 
> as above...

...

> > > 		for (i = 1; i < ARRAY_SIZE(tcs3472_intr_pers) - 1; i++) {
> > > 			if (period <= cycle_us * tcs3472_intr_pers[i])
> > > 				break;
> > > 		}
> > 
> > do {} while () seems better choice here (and do it in reverse order?).
> 
> Could you suggest the do {} while {} form, which seems better? Because I
> think it is already comprehensible.

OK, it's not do {} while

		i = ARRAY_SIZE(tcs3472_intr_pers);
		while (i--) {
			if (period > cycle_us * tcs3472_intr_pers[i])
				break;
		}

if I am not mistaken... OTOH, the for-loop is in the original code, perhaps
better to leave this approach and change separately if needed.

-- 
With Best Regards,
Andy Shevchenko