From: Matti Vaittinen <mazziesaccount@gmail.com>
To: Matti Vaittinen <matti.vaittinen@fi.rohmeurope.com>
Cc: Jonathan Cameron <jic23@kernel.org>,
Lars-Peter Clausen <lars@metafoo.de>,
Liam Beguin <liambeguin@gmail.com>,
Randy Dunlap <rdunlap@infradead.org>,
Masahiro Yamada <masahiroy@kernel.org>,
linux-kernel@vger.kernel.org, linux-iio@vger.kernel.org,
Stephen Boyd <sboyd@kernel.org>,
Maxime Ripard <maxime@cerno.tech>
Subject: Re: [PATCH v5 5/8] iio: test: test gain-time-scale helpers
Date: Fri, 24 Mar 2023 08:29:44 +0200 [thread overview]
Message-ID: <21a888a1-95e3-cdf9-2a1d-1bb8b3d27a16@gmail.com> (raw)
In-Reply-To: <3f33fc551c0698b4cddb0d39911dddf7599c6317.1679474247.git.mazziesaccount@gmail.com>
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! ~~
next prev parent reply other threads:[~2023-03-24 6:31 UTC|newest]
Thread overview: 61+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-22 9:05 [PATCH v5 0/8] Support ROHM BU27034 ALS sensor Matti Vaittinen
2023-03-22 9:05 ` [PATCH v5 1/8] drivers: kunit: Generic helpers for test device creation Matti Vaittinen
2023-03-22 12:04 ` Greg Kroah-Hartman
2023-03-22 12:07 ` Greg Kroah-Hartman
2023-03-22 13:48 ` Matti Vaittinen
2023-03-22 18:57 ` Greg Kroah-Hartman
2023-03-23 7:17 ` Vaittinen, Matti
2023-03-23 8:58 ` Greg Kroah-Hartman
2023-03-23 9:20 ` Matti Vaittinen
2023-03-23 10:25 ` Greg Kroah-Hartman
2023-03-23 10:43 ` Matti Vaittinen
2023-03-23 10:01 ` Matti Vaittinen
2023-03-23 10:27 ` Greg Kroah-Hartman
2023-03-23 11:00 ` Matti Vaittinen
2023-03-23 10:12 ` Maxime Ripard
2023-03-23 10:21 ` Greg Kroah-Hartman
2023-03-23 12:16 ` Matti Vaittinen
2023-03-23 12:29 ` Maxime Ripard
2023-03-23 13:02 ` Matti Vaittinen
2023-03-23 16:36 ` Maxime Ripard
2023-03-24 6:11 ` Matti Vaittinen
2023-03-24 6:34 ` David Gow
2023-03-24 6:51 ` Matti Vaittinen
2023-03-24 9:52 ` David Gow
2023-03-24 10:05 ` Matti Vaittinen
2023-03-24 10:17 ` Matti Vaittinen
2023-03-25 4:35 ` David Gow
2023-03-25 7:26 ` Matti Vaittinen
2023-03-24 12:46 ` Maxime Ripard
2023-03-24 12:31 ` Maxime Ripard
2023-03-25 5:40 ` David Gow
2023-03-29 19:43 ` Maxime Ripard
2023-03-25 17:50 ` Jonathan Cameron
2023-03-26 17:16 ` Lars-Peter Clausen
2023-04-01 15:30 ` Jonathan Cameron
2023-03-29 19:46 ` Maxime Ripard
2023-04-01 15:36 ` Jonathan Cameron
2023-03-24 12:36 ` Maxime Ripard
2023-03-24 12:43 ` Greg Kroah-Hartman
2023-03-24 13:02 ` Maxime Ripard
2023-03-24 13:42 ` Greg Kroah-Hartman
2023-03-22 12:08 ` Greg Kroah-Hartman
2023-03-23 7:30 ` David Gow
2023-03-23 8:35 ` Matti Vaittinen
2023-03-23 9:02 ` Greg Kroah-Hartman
2023-03-23 10:07 ` Maxime Ripard
2023-03-22 9:06 ` [PATCH v5 2/8] drm/tests: helpers: Use generic helpers Matti Vaittinen
2023-03-22 9:06 ` [PATCH v5 3/8] dt-bindings: iio: light: Support ROHM BU27034 Matti Vaittinen
2023-03-22 9:06 ` [PATCH v5 4/8] iio: light: Add gain-time-scale helpers Matti Vaittinen
2023-03-22 9:07 ` [PATCH v5 5/8] iio: test: test " Matti Vaittinen
2023-03-24 6:29 ` Matti Vaittinen [this message]
2023-03-22 9:07 ` [PATCH v5 6/8] MAINTAINERS: Add IIO " Matti Vaittinen
2023-03-22 9:07 ` [PATCH v5 7/8] iio: light: ROHM BU27034 Ambient Light Sensor Matti Vaittinen
2023-03-26 16:19 ` Jonathan Cameron
2023-03-27 7:16 ` Vaittinen, Matti
2023-03-22 9:08 ` [PATCH v5 8/8] MAINTAINERS: Add ROHM BU27034 Matti Vaittinen
2023-03-22 10:01 ` [PATCH v5 0/8] Support ROHM BU27034 ALS sensor Andy Shevchenko
2023-03-22 10:34 ` Javier Martinez Canillas
2023-03-22 10:59 ` Matti Vaittinen
2023-03-22 11:02 ` Andy Shevchenko
2023-03-23 9:28 ` Maxime Ripard
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