linux-kernel - Re: [RFC 3/5] regulator: core: Only apply constraints if available on list voltage

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Date:	Wed, 30 Jul 2014 10:49:25 +0200
From:	Javier Martinez Canillas <javier.martinez@...labora.co.uk>
To:	Mark Brown <broonie@...nel.org>
CC:	Kukjin Kim <kgene.kim@...sung.com>,
	Doug Anderson <dianders@...omium.org>,
	Olof Johansson <olof@...om.net>,
	Yuvaraj Kumar C D <yuvaraj.cd@...il.com>,
	linux-samsung-soc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [RFC 3/5] regulator: core: Only apply constraints if available
 on list voltage

Hello Mark, thanks a lot for all your feedback.

On 07/29/2014 07:18 PM, Mark Brown wrote:
> On Tue, Jul 29, 2014 at 06:28:57PM +0200, Javier Martinez Canillas wrote:
>> 
>> But for load switches that don't define a voltage output, the parent
>> supply voltage is used so the constraints should only be applied if
>> they were defined for the child regulators.
> 
> No, think about what you're doing here and why we're filtering out
> unsettable voltages - this causes problems for consumers on regulators
> that don't have any ability to vary voltages since they will now be able
> to list voltages that they can't select.  
> 

Understood. Thanks for the explanation.

> I would also expect any regulator where the supplied devices are able to
> vary the voltage to explicitly provide a constraint even if the
> implementation is done in a parent regulator.  There may be constraints
> on the child supply which aren't directly present on the parent supply
> and can be ignored if the child supply is turned off.
> 

Agreed, if I explicitly set the voltage constraints on the child supply then
this patch is indeed not needed.

Best regards,
Javier
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