Re: [PATCH v1 4/7] iio: st_sensors: Call st_sensors_power_enable() from bus drivers

[Andy Shevchenko]

On Sun, Apr 18, 2021 at 1:54 PM Jonathan Cameron <jic23@xxxxxxxxxx> wrote:
> On Wed, 14 Apr 2021 22:54:51 +0300
> Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote:
>
> > In case we would initialize two IIO devices from one physical device,
> > we shouldn't have a clash on regulators. That's why move
> > st_sensors_power_enable() call from core to bus drivers.
>
> Why is this a problem?

You can't have two regulators of the same name on the same device.
IIRC the regulator framework produces a good splat for this.

>  The two instances would double up and both get +
> enable + disable the regulators.  However, that shouldn't matter as
> they are reference counted anyway.
>
> Perhaps an example?  Even in patch 6 I can only see that it is wasteful
> to do it twice, rather than wrong as such.

Believe me, I would like to avoid that, but it seems a limitation of
the regulator framework. It simply produces a splat. I'll try to
reproduce it again (because this series started like a couple of years
ago, just eventually I found a time to clean up and submit) and will
tell you how it is going.


-- 
With Best Regards,
Andy Shevchenko