linux-kernel - Re: [PATCH 3/4] regulator: Add a regulator driver for the PM8008 PMIC

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Message-ID: <fbd80685df0a86b30868187e2556d67f@codeaurora.org>
Date:   Tue, 28 Sep 2021 17:46:54 +0530
From:   skakit@...eaurora.org
To:     Mark Brown <broonie@...nel.org>
Cc:     Andy Gross <agross@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Lee Jones <lee.jones@...aro.org>,
        Liam Girdwood <lgirdwood@...il.com>, mka@...omium.org,
        swboyd@...omium.org, Das Srinagesh <gurus@...eaurora.org>,
        David Collins <collinsd@...eaurora.org>, kgunda@...eaurora.org,
        Subbaraman Narayanamurthy <subbaram@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] regulator: Add a regulator driver for the PM8008 PMIC

Hi Mark,

Thanks for reviewing the changes!

On 2021-09-17 21:08, Mark Brown wrote:
> On Fri, Sep 17, 2021 at 04:15:37PM +0530, Satya Priya wrote:
> 
>> +static int pm8008_regulator_is_enabled(struct regulator_dev *rdev)
>> +{
>> +	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
>> +	int rc;
>> +	u8 reg;
>> +
>> +	rc = pm8008_read(pm8008_reg->regmap,
>> +			LDO_ENABLE_REG(pm8008_reg->base), &reg, 1);
>> +	if (rc < 0) {
>> +		pr_err("failed to read enable reg rc=%d\n", rc);
>> +		return rc;
>> +	}
>> +
>> +	return !!(reg & ENABLE_BIT);
>> +}
> 
> This could just be regulator_is_enabled_regmap().  There's also a lot 
> of
> instances in the driver where it's using pr_err() not dev_err() (and
> similarly for the debug prints).
> 

Okay, I'll use the helper regulator_is_enabled_regmap() here and remove 
this completely.

>> +
>> +static int pm8008_regulator_enable(struct regulator_dev *rdev)
>> +{
>> +	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
>> +	int rc, current_uv, delay_us, delay_ms, retry_count = 10;
>> +	u8 reg;
> 
> This is the regmap helper.
> 

Okay, I'll use regulator_enable_regmap().

>> +	/*
>> +	 * Wait for the VREG_READY status bit to be set using a timeout 
>> delay
>> +	 * calculated from the current commanded voltage.
>> +	 */
>> +	delay_us = STARTUP_DELAY_USEC
>> +			+ DIV_ROUND_UP(current_uv, pm8008_reg->step_rate);
>> +	delay_ms = DIV_ROUND_UP(delay_us, 1000);
> 
> Set poll_enable_time and implement get_status() then this will be
> handled by the core.
> 

Anyway I will be removing this API.

>> +static int pm8008_regulator_disable(struct regulator_dev *rdev)
>> +{
> 
> Use the regmap helper.
> 

Ok, I'll use regulator_disable_regmap.

>> +	rc = pm8008_write_voltage(pm8008_reg, min_uv, max_uv);
>> +	if (rc < 0)
>> +		return rc;
> 
> This is the only place where write_voltage() is called, may as well 
> just
> inline it.
> 

Okay.

>> +	init_voltage = -EINVAL;
>> +	of_property_read_u32(reg_node, "qcom,init-voltage", &init_voltage);
> 
> Why does this property exist and if it's needed why is it specific to
> this device?  It looks like the device allows you to read the voltage 
> on
> startup from the regmap.
> 

I think it is not necessary, will remove it.

>> +	init_data = of_get_regulator_init_data(dev, reg_node,
>> +						&pm8008_reg->rdesc);
>> +	if (init_data == NULL) {
>> +		dev_err(dev, "%s: failed to get regulator data\n", name);
>> +		return -ENODATA;
>> +	}
>> +	if (!init_data->constraints.name) {
>> +		dev_err(dev, "%s: regulator name missing\n", name);
>> +		return -EINVAL;
>> +	}
> 
> Just let the core find the init data for you, there is no reason to
> insist on a system provided name - that is an entirely optional 
> property
> for systems to use, there is no reason for a regulator driver to care.
> 

OK, I will remove this if check.

>> +	init_data->constraints.input_uV = init_data->constraints.max_uV;
>> +	init_data->constraints.valid_ops_mask |= REGULATOR_CHANGE_STATUS
>> +						| REGULATOR_CHANGE_VOLTAGE;
> 
> This is absolutely not something that a regulator driver should be
> doing, the whole point with constraints is that they come from the
> machine.
> 

Okay I will remove this.

>> +static int pm8008_parse_regulator(struct regmap *regmap, struct 
>> device *dev)
>> +{
>> +	int rc = 0;
>> +	const char *name;
>> +	struct device_node *child;
>> +	struct pm8008_regulator *pm8008_reg;
>> +
>> +	/* parse each subnode and register regulator for regulator child */
>> +	for_each_available_child_of_node(dev->of_node, child) {
>> +		pm8008_reg = devm_kzalloc(dev, sizeof(*pm8008_reg), GFP_KERNEL);
>> +		if (!pm8008_reg)
> 
> You shouldn't be doing this, just unconditionally register all the
> regulators supported by the chip.  If they don't appear in the DT 
> that's
> totally fine - it gives read only access which can be useful for
> diagnostics.

Okay will remove this check as well.

-Satya Priya.