Re: [PATCH v3 2/6] iio: light: Add gain-time-scale helpers

[Matti Vaittinen]

On 3/13/23 15:29, Andy Shevchenko wrote:
> On Mon, Mar 13, 2023 at 03:11:52PM +0200, Matti Vaittinen wrote:
> > On 3/13/23 14:40, Andy Shevchenko wrote:
> > > On Sun, Mar 12, 2023 at 05:08:48PM +0000, Jonathan Cameron wrote:
> > > > On Sun, 12 Mar 2023 17:06:38 +0000
> > > > Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
>
> ...
>
> > > > Ah. I forgot the tests that don't have a device so can't use devm.
> > >
> > > Why not? I have seen, IIRC, test cases inside the kernel that fakes the device
> > > for that.
> >
> > I'd appreciated any pointer for such an example if you have one at hand. (I
> > can do the digging if you don't though!)
> >
> > I am not a fan of unit tests. They add huge amount of inertia to
> > development, and in worst case, they stop people from contributing where
> > improving a feature requires test code modification(s). And harder the test
> > code is to understand, worse the unwanted side-effects. Also, harder the
> > test code is to read, more time and effort it requires to analyze a test
> > failure... Hence, I am _very_ conservative what comes to adding size of test
> > code with anything that is not strictly required.
> >
> > After that being said, unit tests are a great tool when carefully used - and
> > I assume/hope stubbing a device for devm_ tests does not add much extra...
> > But let me see if I can find an example :)
>
> drivers/gpu/drm/tests/drm_managed_test.c ?
>
> (somewhere underneath:
>
>   ret = platform_driver_register(&fake_platform_driver);
>
> which suggests... what exactly? :-)

Thanks!

--Matti

--
Matti Vaittinen
Linux kernel developer at ROHM Semiconductors
Oulu Finland

~~ When things go utterly wrong vim users can always type :help! ~~