Re: [PATCH] Input: ads7846: add regulator support

[Mike Rapoport <mike@compulab.co.il>]

Mark Brown wrote:
> On Fri, Feb 05, 2010 at 10:45:09PM +0200, Mike Rapoport wrote:
>> On Thu, Feb 4, 2010 at 6:21 PM, Mark Brown
> 
>>> The bodge I'm thinking of would do something like log an error and
>>> substitute in a dummy regulator when regulator_get() would have failed
>>> so that the driver sees behaviour equivalent to the stubbed regulator
>>> API if the bodge is active.  A central thing seems much more sensible
>>> here - there's nothing specific to this driver going on here and having
>>> the API behave in a consistent manner seems good.
> 
>> I agree that such approach have more sense than checking for -ENODEV
>> in each and every driver that uses the regulator framework. I just
>> wonder, if there should be some mechanism that  can switch the
>> substitution of the dummy regulators on and off. And if yes, how
>> should the platform code communicate with the regulator core the need
>> for such dummy regulators...
> 
> So, having thought about this a bit more we actually have two different
> use cases here.  One is where you've got a system which has software
> controllable regulators for everything but may not have plumbed in all
> the supplies, the other is for systems where only a very few supplies
> are on software controlled regulators which are just trying to save the
> hassle of hooking up the bulk of the supplies to fixed voltage
> regulators.  These two use cases should probably be handled differently
> - the first one is really expected to have all the supplies hooked up
> and so should warn when using the bodge regulator but the warning isn't
> helpful in the second case.

Sounds right to me.

> We already have some support for boards to set up the API in the form of
> regulator_set_full_constraints() so we could do something similar for
> dummy regulators, or create a new single API to set a bunch of options
> via a struct which is probably less hassle going forward.

Struct sounds more reasonable that just a call to e.g.
regulator_warn_dummy_fixed_regulator :)

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-- 
Sincerely yours,
Mike.