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Date: Tue, 5 Oct 2010 15:52:24 -0700
From: Mark Brown <broonie@opensource.wolfsonmicro.com>
To: Linus Walleij <linus.ml.walleij@gmail.com>
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Subject: Re: [PATCH v2] Input: Make ADS7846 independent on regulator
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On Wed, Oct 06, 2010 at 12:09:39AM +0200, Linus Walleij wrote:

> This wrapper function will accept non-existing regulators and
> not treat them as errors. Consumers will have to NULL-check their
> regulators.

No, this is actively unhelpful.  If consumers can null check their
regulators then they can just as well do an IS_ERR() check and if we
just eat null pointers like this then the API doesn't degrade gracefully
when it can't implement things - for example, your regulator_set_voltage() 
will report success when it fails to set a voltage which is going to
upset any consumer that thinks it did actually change the current
voltage.

The existing dummy regulator support already does all this in a manner
which is much less invasive for the core.