linux-kernel - Re: [NEW DRIVER V3 8/8] DA9058 REGULATOR driver

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Date:	Mon, 17 Sep 2012 06:40:18 -0400
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	"Opensource [Anthony Olech]" <anthony.olech.opensource@...semi.com>
Cc:	Liam Girdwood <lrg@...com>, Guenter Roeck <linux@...ck-us.net>,
	Jean Delvare <khali@...ux-fr.org>,
	Randy Dunlap <rdunlap@...otime.net>,
	LKML <linux-kernel@...r.kernel.org>,
	David Dajun Chen <david.chen@...semi.com>
Subject: Re: [NEW DRIVER V3 8/8] DA9058 REGULATOR driver

On Mon, Sep 17, 2012 at 10:29:43AM +0000, Opensource [Anthony Olech] wrote:

> > Why is this function writing to the hardware, especially writing the same value
> > every time?

> the ramp_register is DA9058_SUPPLY_REG and it is marked as volitile.
> Writing to the ramp enable bit starts the voltage change. When the PMIC has
> finished making the change it resets the bit. Thus to make another voltage
> change the bit needs to be set again.

This function is retrieving the amount of time it would take to set the
voltage.  Why would it be starting a voltage ramp?  The fact that it's
not setting the new voltage in the hardware ought to be a warning sign
here...
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