linux-kernel - Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323 regulator

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Message-ID: <1453965401.19407.18.camel@mtksdaap41>
Date:	Thu, 28 Jan 2016 15:16:41 +0800
From:	Henry Chen <henryc.chen@...iatek.com>
To:	Mark Brown <broonie@...nel.org>
CC:	John Crispin <blogic@...nwrt.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	<linux-kernel@...r.kernel.org>,
	<linux-mediatek@...ts.infradead.org>,
	"Matthias Brugger" <matthias.bgg@...il.com>,
	Chen Zhong <chen.zhong@...iatek.com>,
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH V4 2/2] regulator: mt6323: Add support for MT6323
 regulator

Hi Mark,

On Wed, 2016-01-27 at 14:41 +0000, Mark Brown wrote:
> On Wed, Jan 27, 2016 at 01:00:59PM +0100, John Crispin wrote:
> 
> > +		/* Constrain board-specific capabilities according to what
> > +		 * this driver and the chip itself can actually do.
> > +		 */
> > +		c = rdev->constraints;
> > +		c->valid_modes_mask |= REGULATOR_MODE_NORMAL |
> > +				       REGULATOR_MODE_STANDBY;
> > +		c->valid_ops_mask |= REGULATOR_CHANGE_MODE;
> 
> No, drivers should *never* enable things that weren't explictly enabled
> by the machine constraints.  This misses the whole point of having
> constraints.  They are there so that the system integrator can enable
> the functionality that is safe on a given board.  

Okay..the constrains should be define on device tree.
But which optional properties was suitable to fill on device tree if consumers want to call
regulator_set_mode directly ?
I have check the of_regulator.c and not found the suitable property name which can set valid_modes_mask & valid_ops_mask.

Thanks,
Henry 
> 
> The comment is also inaccurate, it claims it's imposing constraints but
> in fact it's adding additional permissions.
> _______________________________________________
> Linux-mediatek mailing list
> Linux-mediatek@...ts.infradead.org
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