linux-kernel - RE: [PATCH V3] regulator: DA9211 : new regulator driver

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Date:	Mon, 30 Jun 2014 16:11:36 +0900
From:	<james.ban.opensource@...semi.com>
To:	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	Support Opensource <support.opensource@...semi.com>,
	LKML <linux-kernel@...r.kernel.org>
CC:	David Dajun Chen <david.chen@...semi.com>
Subject: RE: [PATCH V3] regulator: DA9211 : new regulator driver

> -----Original Message-----
> From: Mark Brown [mailto:broonie@...nel.org]
> Sent: Saturday, June 28, 2014 12:01 AM
> To: Opensource [James Seong-Won Ban]
> Cc: Liam Girdwood; Support Opensource; LKML; David Dajun Chen
> Subject: Re: [PATCH V3] regulator: DA9211 : new regulator driver
> 
> On Mon, Jun 02, 2014 at 08:17:03AM +0100, James Ban wrote:
> 
> > This is the driver for the Dialog DA9211 Multi-phase 12A DC-DC Buck
> > Converter regulator. It communicates via an I2C bus to the device.
> 
> This *still* seems to have all the same problems with inconsistent handling of
> the A and B register sets
> 
> > +	/* Make sure to exit from suspend mode on enable */
> > +	if (regulator->reg_rselect == DA9211_RSEL_NO_GPIO) {
> > +		ret = regmap_update_bits(chip->regmap, info->conf.reg,
> > +					info->conf.sel_mask,
> > +					DA9211_VBUCKA_SEL_A);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> 
> Here it forces set A if and only if in no GPIO mode but...
> 
> > +static int da9211_regulator_set_suspend_voltage(struct regulator_dev *rdev,
> > +						int uV)
> > +{
> > +	struct da9211_regulator *regulator = rdev_get_drvdata(rdev);
> > +	struct da9211_regulator_info *info = regulator->info;
> > +	struct da9211 *chip = regulator->da9211;
> > +	int ret;
> > +
> > +	ret = regulator_map_voltage_linear(rdev, uV, uV);
> > +	if (ret < 0)
> > +		return ret;
> > +
> > +	return regmap_update_bits(chip->regmap, info->volt.reg_b,
> > +				 info->volt.v_mask, ret);
> > +}
> 
> ...this unconditionally uses set B and...
> 
> > +static int da9211_suspend_enable(struct regulator_dev *rdev) {
> > +	struct da9211_regulator *regulator = rdev_get_drvdata(rdev);
> > +	struct da9211_regulator_info *info = regulator->info;
> > +	struct da9211 *chip = regulator->da9211;
> > +
> > +	/* Select register set B for voltage ramping. */
> > +	if (regulator->reg_rselect == DA9211_RSEL_NO_GPIO)
> > +		return regmap_update_bits(chip->regmap, info->conf.reg,
> > +					info->conf.sel_mask,
> > +					DA9211_VBUCKA_SEL_B);
> > +	else
> > +		return 0;
> > +}
> 
> ...this uses B if not using a GPIO and otherwise reports success without actually
> doing anything (which seems buggy).  These behaviours aren't compatible with
> each other, set_suspend_voltage() will break if set B is selected by GPIO for
> example.
> 
> Please either go through and try to make these things all consistent or
> (probably better) strip out the suspend and probably GPIO handling for now, get
> the bulk of the driver merged, and then come back and try to deal with those
> tricky bits.
Though the GPIO control and suspend was introduced for more usability of user,
You seems to want more strict compatibility at any case.
As your suggestion, I will strip out the suspend and GPIO handling.
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