linux-kernel - Re: [PATCH 6/6] regulator: anatop: set default voltage selector for pcie

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Message-ID: <1492013514.15082.35.camel@pengutronix.de>
Date:   Wed, 12 Apr 2017 18:11:54 +0200
From:   Lucas Stach <l.stach@...gutronix.de>
To:     Dong Aisheng <dongas86@...il.com>
Cc:     Mark Brown <broonie@...nel.org>,
        Dong Aisheng <aisheng.dong@....com>,
        Richard Zhu <hongxing.zhu@....com>, lgirdwood@...il.com,
        linux-kernel@...r.kernel.org, kernel@...gutronix.de,
        yibin.gong@....com, shawnguo@...nel.org,
        linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH 6/6] regulator: anatop: set default voltage selector for
 pcie

Am Donnerstag, den 13.04.2017, 15:41 +0800 schrieb Dong Aisheng:
> On Tue, Apr 11, 2017 at 09:40:03PM +0100, Mark Brown wrote:
> > On Wed, Apr 12, 2017 at 09:58:47AM +0800, Dong Aisheng wrote:
> > > Set the initial voltage selector for vddpcie in case it's disabled
> > > by default.
> > 
> > Why is this the only anatop regulator which can have this problem and
> > how do we know this is a good value?
> 
> Anatop regulator has no separate gate bit.
> e.g.
> 00000 Power gated off
> 00001 Target core voltage = 0.725V
> ...
> So it may have no valid default voltage in case it's disabled in
> bootloader.
> e.g. regulator_enable() may not work.
> 
> The default voltage 1.100v this patch sets is defined in reference
> manual.

Huh? Shouldn't regulator_enable bring the voltage in a range defined by
the constraints in the DT?

Regards,
Lucas