Messages in this thread | | | Date | Fri, 24 Mar 2023 08:29:44 +0200 | From | Matti Vaittinen <> | Subject | Re: [PATCH v5 5/8] iio: test: test gain-time-scale helpers |
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On 3/22/23 11:07, Matti Vaittinen wrote: > Some light sensors can adjust both the HW-gain and integration time. > There are cases where adjusting the integration time has similar impact > to the scale of the reported values as gain setting has. > > IIO users do typically expect to handle scale by a single writable 'scale' > entry. Driver should then adjust the gain/time accordingly. > > It however is difficult for a driver to know whether it should change > gain or integration time to meet the requested scale. Usually it is > preferred to have longer integration time which usually improves > accuracy, but there may be use-cases where long measurement times can be > an issue. Thus it can be preferable to allow also changing the > integration time - but mitigate the scale impact by also changing the gain > underneath. Eg, if integration time change doubles the measured values, > the driver can reduce the HW-gain to half. > > The theory of the computations of gain-time-scale is simple. However, > some people (undersigned) got that implemented wrong for more than once. > Hence some gain-time-scale helpers were introduced. > > Add some simple tests to verify the most hairy functions. > > Signed-off-by: Matti Vaittinen <mazziesaccount@gmail.com> > > --- > Changes: > v4 => v5: > - remove empty lines from Kconfig > - adapt to drop of the non devm iio_init
I think you may want to skip reviewing this specific patch. After having a chat with Greg, David, and Maxime it seems this will be changed quite a bit for v6.
Most notably, I am planning to drop the generic helpers and struct gts_test. I'll also simplify the signatures of __test_init_iio_gain_scale() and test_init_iio_gain_scale().
Yours, -- Matti
-- Matti Vaittinen Linux kernel developer at ROHM Semiconductors Oulu Finland
~~ When things go utterly wrong vim users can always type :help! ~~
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