linux-kernel - Re: [PATCH] regulator: add driver for MAX8660/8661

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Date:	Thu, 24 Sep 2009 20:07:27 +0200
From:	Wolfram Sang <w.sang@...gutronix.de>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
Cc:	linux-kernel@...r.kernel.org, Liam Girdwood <lrg@...mlogic.co.uk>
Subject: Re: [PATCH] regulator: add driver for MAX8660/8661


> > +	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?

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |

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