linux-kernel - Re: [RFC PATCH 2/8] regulator: Add Dialog DA906x voltage regulators support.

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Date:	Wed, 29 Aug 2012 15:50:00 +0100
From:	Krystian Garbaciak <krystian.garbaciak@...semi.com>
To:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
CC:	<linux-kernel@...r.kernel.org>, <rtc-linux@...glegroups.com>,
	<lm-sensors@...sensors.org>, <linux-input@...r.kernel.org>,
	<linux-watchdog@...r.kernel.org>, <linux-leds@...r.kernel.org>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	Liam Girdwood <lrg@...com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	Alessandro Zummo <a.zummo@...ertech.it>,
	Jean Delvare <khali@...ux-fr.org>,
	Dmitry Torokhov <dmitry.torokhov@...il.com>,
	Ashish Jangam <ashish.jangam@...tcummins.com>,
	Andrew Jones <drjones@...hat.com>,
	Donggeun Kim <dg77.kim@...sung.com>,
	Philippe Rétornaz <philippe.retornaz@...l.ch>,
	"Wim Van Sebroeck" <wim@...ana.be>,
	Bryan Wu <bryan.wu@...onical.com>,
	Richard Purdie <rpurdie@...ys.net>,
	Anthony Olech <anthony.olech@...semi.com>
Subject: Re: [RFC PATCH 2/8] regulator: Add Dialog DA906x voltage regulators support.

> > +static int da906x_set_voltage(struct regulator_dev *rdev,
> > +				int min_uV, int max_uV, unsigned *selector)
> > +{
> > +	struct da906x_regulator *regl = rdev_get_drvdata(rdev);
> > +	const struct field *fvol = &regl->info->voltage;
> > +	int ret;
> > +	unsigned val;
> > +
> > +	val = regulator_map_voltage_linear(rdev, min_uV, max_uV);
> > +	if (val < 0)
> > +		return -EINVAL;
> > +
> > +	val = (val + fvol->offset) << fvol->shift;
> > +	ret = da906x_reg_update(regl->hw, fvol->addr, fvol->mask, val);
> > +	if (ret >= 0)
> > +		*selector = val;
> > +
> > +	return ret;
> > +}
> 
> This is just set_voltage_sel_regmap().

Because, for some regulators, this is required: val += fvol->offset,
I was only able to reduce it to the following form.

+static int da9063_set_voltage(struct regulator_dev *rdev,
+			      int min_uV, int max_uV, unsigned *selector)
+{
+	struct da9063_regulator *regl = rdev_get_drvdata(rdev);
+	const struct field *fvol = &regl->info->voltage;
+	int ret;
+	unsigned val;
+
+	val = regulator_map_voltage_linear(rdev, min_uV, max_uV);
+	if (val < 0)
+		return -EINVAL;
+
+	val += fvol->offset;
+
+	ret = regulator_set_voltage_sel_regmap(rdev, val);
+	if (ret >= 0)
+		*selector = val;
+
+	return ret;
+}

> > +static int da906x_enable(struct regulator_dev *rdev)
> > +{
> > +	struct da906x_regulator *regl = rdev_get_drvdata(rdev);
> > +	int ret;
> > +
> > +	if (regl->info->suspend.mask) {
> > +		/* Make sure to exit from suspend mode on enable */
> > +		ret = da906x_reg_clear_bits(regl->hw, regl->info->suspend.addr,
> > +					    regl->info->suspend.mask);
> > +		if (ret < 0)
> > +			return ret;
> > +
> > +		/* BUCKs need mode update after wake-up from suspend state. */
> > +		ret = da906x_update_mode_internal(regl, SYS_STATE_NORMAL);
> > +		if (ret < 0)
> > +			return ret;
> > +	}
> > +
> > +	return regulator_enable_regmap(rdev);
> 
> If suspend_mask is optional the regulators using it should just use the
> standard operation.

I guess, you meant here to call regulator_enable_regmap() directly for
regulators NOT using suspend.mask. Then, I will do it.

> > +/* Regulator event handlers */
> > +irqreturn_t da906x_ldo_lim_event(int irq, void *data)
> 
> By "event handler" you mean "interrupt"

Yes. I think, I will update the comment line.

> > +	bits = da906x_reg_read(hw, DA906X_REG_STATUS_D);
> > +	if (bits < 0)
> > +		return IRQ_HANDLED;
> 
> If you fail to detect an interrupt you report that you handled one...?

For me there is no sensible return value for this case.
However, I consider changing the reaction on read failure by reporting event
for all regulators, that might cause this interrupt:
+	bits = da9063_reg_read(hw, DA9063_REG_STATUS_D);
+	if (bits < 0)
+		bits = ~0;

I will update the driver according to your remaining comments.

Thank you for your comments,
Krystian

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