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From: Liam Girdwood <lrg@slimlogic.co.uk>
To: Wolfram Sang <w.sang@pengutronix.de>
Cc: Mark Brown <broonie@opensource.wolfsonmicro.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH] regulator: add driver for MAX8660/8661
Date: Thu, 24 Sep 2009 19:21:46 +0100	[thread overview]
Message-ID: <1253816506.11624.889.camel@vega> (raw)
In-Reply-To: <20090924180727.GA6408@pengutronix.de>

On Thu, 2009-09-24 at 20:07 +0200, Wolfram Sang wrote:
> > > +	if (MAX8660_DCDC_MIN_UV + selector * MAX8660_DCDC_STEP > max_uV)
> > > +		return -EINVAL;
> > 
> > Not important but using list_voltage() here would be a little nicer.
> 
> Well, uhm, yeah :)
> 
> > > +static struct regulator_ops max8660_dcdc_ops = {
> > > +	.is_enabled = max8660_dcdc_is_enabled,
> > > +	.list_voltage = max8660_dcdc_list,
> > > +	.set_voltage = max8660_dcdc_set,
> > > +	.get_voltage = max8660_dcdc_get,
> > > +	/* no set_mode() & friends: forced PWM does not save any power */
> > 
> > Forced PWM is normally a power loss - the benefit it gives is the
> > ability to respond to sudden spikes in load without voltage droops.  The
> > power benefit from not having it enabled is usually only apparent at
> > lower loads.
> 
> Understood. Well, as this chip automatically switches PWM on/off depending on
> the load (formula is in the datasheet), it seems to me that the forced-PWM mode
> is mainly used for systems which prefer low-noise on the signal. So, the above
> comment could just be dropped. Liam, could you do this, or shall I resend?

Would be easier for me if you could resend. Mark and I are at LPC today
so not really in a position to code (or even answers mails quickly).

Thanks

Liam


  parent reply	other threads:[~2009-09-24 18:21 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-09-24 13:24 [PATCH] regulator: add driver for MAX8660/8661 Wolfram Sang
2009-09-24 17:39 ` Mark Brown
2009-09-24 18:07   ` Wolfram Sang
2009-09-24 18:13     ` Mark Brown
2009-09-24 18:21     ` Liam Girdwood [this message]
2009-09-25  7:39       ` [PATCH V2] " Wolfram Sang
2009-09-25 17:23         ` Mark Brown
2009-09-29 16:46         ` Liam Girdwood

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