linux-kernel - Re: [PATCH v3 1/2] ASoC: codecs: add TA5720 digital amplifier DT bindings

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Date:	Tue, 26 Apr 2016 12:00:51 -0500
From:	Andreas Dannenberg <dannenberg@...com>
To:	Mark Brown <broonie@...nel.org>
CC:	<alsa-devel@...a-project.org>, <devicetree@...r.kernel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Jaroslav Kysela <perex@...ex.cz>,
	Takashi Iwai <tiwai@...e.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 1/2] ASoC: codecs: add TA5720 digital amplifier DT
 bindings

On Tue, Apr 26, 2016 at 05:50:06PM +0100, Mark Brown wrote:
> On Tue, Apr 26, 2016 at 11:14:25AM -0500, Andreas Dannenberg wrote:
> > On Tue, Apr 26, 2016 at 04:37:07PM +0100, Mark Brown wrote:
> > > On Mon, Apr 25, 2016 at 03:17:35PM -0500, Andreas Dannenberg wrote:
> 
> > > > +Optional properties:
> 
> > > > +- dvdd-supply : phandle to a 3.3-V supply for the digital circuitry
> > > > +- pvdd-supply : phandle to a supply used for the Class-D amp and the analog
> 
> > > This suggests that the device doesn't need power...  
> 
> > no power, now that would be nice! :)  What this was supposed to mean is
> > that the properties are optional, the power of course is not. The DT has
> 
> They should only be optional if they may really be missing.  We may
> attempt to be liberal in the DTs we accept but we should not encourage
> sloppily written DTs.

Thanks for the guidance and the background. Will move them to "required"
but I'll wait a few more days before re-submitting in case there is
additional feedback on the patch series.

Regards,
Andreas

> 
> > really no control over how I wire up my HW and I'd argue most folks just
> > permanently power the TAS5720 since the shutdown current is just a few
> > uAs IIRC in order to save some BOM cost. But I suppose the DT description
> > is such that the Kernel can more intelligently handle things based on
> > what the driver is doing if somebody choses and implements additional
> > regulator/power switch HW. Or did I misunderstand your point?
> 
> It doesn't really matter if a given system ends up controlling things
> actively, we still want to be consistent in describing them since it is
> less error prone when it does become relevant.