linux-kernel - Re: [PATCH v3 RESEND] regulator: Add S5M8767A regulator driver

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Message-ID: <20111229105729.GF2909@opensource.wolfsonmicro.com>
Date:	Thu, 29 Dec 2011 10:57:30 +0000
From:	Mark Brown <broonie@...nsource.wolfsonmicro.com>
To:	Sangbeom Kim <sbkim73@...sung.com>
Cc:	lrg@...com, sameo@...ux.intel.com, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 RESEND] regulator: Add S5M8767A regulator driver

On Thu, Dec 29, 2011 at 07:55:25AM +0900, Sangbeom Kim wrote:

> +static int s5m8767_get_voltage_sel(struct regulator_dev *rdev)
> +{

...

> +	if (rdev->desc && rdev->desc->ops && rdev->desc->ops->list_voltage)
> +		return rdev->desc->ops->list_voltage(rdev, val);
> +
> +	return val;
> +}

This looks really strange - get_voltage_sel() should return a selector
but the return value of list_voltage() is a voltage.

> +static int s5m8767_reg_disable_suspend(struct regulator_dev *rdev)
> +{
> +	struct s5m8767_info *s5m8767 = rdev_get_drvdata(rdev);
> +	int ret, reg;
> +	int  mask = 0, pattern = 0;
> +	int reg_id = s5m8767_get_reg_id(rdev);
> +
> +	switch (reg_id) {
> +	case S5M8767_LDO1 ... S5M8767_LDO28:
> +		mask = 0xc0;
> +		pattern = 0xc0;
> +		break;
> +	case S5M8767_BUCK1 ... S5M8767_BUCK9:
> +		mask = 0xc0;
> +		pattern = 0xc0;
> +		break;
> +	}

Looks like mask and pattern are always the same?  Shouldn't this return
an error if reg_id is out of bounds?

> +	ret = s5m8767_get_register(rdev, &reg);
> +	if (ret)
> +		return ret;
> +
> +	return s5m_reg_update(s5m8767->iodev, reg, ~pattern, mask);

The above looks like it's going to update the same registers as the
regular enable and disable which isn't right, this function is for
updating suspend mode configuration.

> +static int s5m8767_set_voltage_time_sel(struct regulator_dev *rdev,
> +					     unsigned int old_sel,
> +					     unsigned int new_sel)
> +{

> +	s5m_reg_read(s5m8767->iodev, reg, &val);
> +	val = val & mask;
> +
> +	if (old_sel < new_sel)
> +		return DIV_ROUND_UP(desc->step * (i - val),
> +					s5m8767->ramp_delay);
> +	else
> +		return 0;

Why does this function need to read from the hardware?  It's not
reading a ramp configuration from the hardware and the start and finish
selectors are both supplied as arguments.

> +	size = sizeof(struct regulator_dev *) * S5M8767_REG_MAX;
> +	s5m8767->rdev = kzalloc(size, GFP_KERNEL);
> +	if (!s5m8767->rdev) {
> +		kfree(s5m8767);

You shouldn't mix devm_ and regular functions.

> +		return -ENOMEM;
> +	}

Why not use devm_kzalloc() for this too?

> +	s5m8767->num_regulators = pdata->num_regulators;

Just pass in fixed size arrays of regulator configurations - the core
can handle unconfigured regulators.

> +	do {
> +		ret = s5m_reg_read(s5m8767->iodev, reg, &val);
> +		if (ret)
> +			return ret;
> +
> +		s5m_reg_update(s5m8767->iodev, reg,
> +				((val & 0x3f) | 0x40), 0xff);
> +		reg++;
> +		if ((reg == S5M8767_REG_LDO9CTRL) ||
> +			(reg == S5M8767_REG_LDO11CTRL) ||
> +			(reg == S5M8767_REG_LDO13CTRL) ||
> +			(reg == S5M8767_REG_LDO17CTRL))
> +			reg++;
> +	} while (reg <= S5M8767_REG_LDO16CTRL);

What does this do?

> +	if (s5m8767->buck2_ramp || s5m8767->buck3_ramp
> +		|| s5m8767->buck4_ramp) {
> +		if (s5m8767->ramp_delay < 15)
> +			s5m_reg_update(s5m8767->iodev, S5M8767_REG_DVSRAMP,
> +					s5m8767->ramp_delay - 1, 0xf0);
> +		else if (s5m8767->ramp_delay == 15)
> +			s5m_reg_update(s5m8767->iodev, S5M8767_REG_DVSRAMP,
> +					0xc0, 0xf0);
> +		else if (s5m8767->ramp_delay == 25)
> +			s5m_reg_update(s5m8767->iodev, S5M8767_REG_DVSRAMP,
> +					0xd0, 0xf0);
> +		else if (s5m8767->ramp_delay == 50)
> +			s5m_reg_update(s5m8767->iodev, S5M8767_REG_DVSRAMP,
> +					0xe0, 0xf0);
> +		else if (s5m8767->ramp_delay == 100)
> +			s5m_reg_update(s5m8767->iodev, S5M8767_REG_DVSRAMP,
> +					0xf0, 0xf0);
> +		else
> +			s5m_reg_update(s5m8767->iodev, S5M8767_REG_DVSRAMP,
> +					0x90, 0xf0);
> +	}

This looks like a switch statement.
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