diff mbox series

[3/4] regulator: Add a regulator driver for the PM8008 PMIC

Message ID 1631875538-22473-4-git-send-email-skakit@codeaurora.org (mailing list archive)
State Superseded
Headers show
Series Add Qualcomm Technologies, Inc. PM8008 regulator driver | expand

Commit Message

Satya Priya Sept. 17, 2021, 10:45 a.m. UTC
From: satya priya <skakit@codeaurora.org>

Qualcomm Technologies, Inc. PM8008 is an I2C controlled PMIC
containing 7 LDO regulators.  Add a PM8008 regulator driver to
support PMIC regulator management via the regulator framework.

Signed-off-by: satya priya <skakit@codeaurora.org>
---
 drivers/regulator/Kconfig                 |   9 +
 drivers/regulator/Makefile                |   1 +
 drivers/regulator/qcom-pm8008-regulator.c | 441 ++++++++++++++++++++++++++++++
 3 files changed, 451 insertions(+)
 create mode 100644 drivers/regulator/qcom-pm8008-regulator.c

Comments

Mark Brown Sept. 17, 2021, 3:38 p.m. UTC | #1
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).

> +
> +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.

> +	/*
> +	 * 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.

> +static int pm8008_regulator_disable(struct regulator_dev *rdev)
> +{

Use the regmap helper.

> +	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.

> +	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.

> +	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.

> +	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.

> +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.
Satya Priya Sept. 28, 2021, 12:16 p.m. UTC | #2
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.
diff mbox series

Patch

diff --git a/drivers/regulator/Kconfig b/drivers/regulator/Kconfig
index e35cca5..888ce30 100644
--- a/drivers/regulator/Kconfig
+++ b/drivers/regulator/Kconfig
@@ -916,6 +916,15 @@  config REGULATOR_PWM
 	  This driver supports PWM controlled voltage regulators. PWM
 	  duty cycle can increase or decrease the voltage.
 
+config REGULATOR_QCOM_PM8008
+	tristate "Qualcomm Technologies, Inc. PM8008 PMIC regulators"
+	depends on MFD_QCOM_PM8008
+	help
+	  Select this option to get support for the voltage regulators
+	  of Qualcomm Technologies, Inc. PM8008 PMIC chip. PM8008 has 7 LDO
+	  regulators. This driver provides support for basic operations like
+	  set/get voltage and enable/disable.
+
 config REGULATOR_QCOM_RPM
 	tristate "Qualcomm RPM regulator driver"
 	depends on MFD_QCOM_RPM
diff --git a/drivers/regulator/Makefile b/drivers/regulator/Makefile
index 9e382b5..5e935ff 100644
--- a/drivers/regulator/Makefile
+++ b/drivers/regulator/Makefile
@@ -100,6 +100,7 @@  obj-$(CONFIG_REGULATOR_MT6380)	+= mt6380-regulator.o
 obj-$(CONFIG_REGULATOR_MT6397)	+= mt6397-regulator.o
 obj-$(CONFIG_REGULATOR_MTK_DVFSRC) += mtk-dvfsrc-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_LABIBB) += qcom-labibb-regulator.o
+obj-$(CONFIG_REGULATOR_QCOM_PM8008) += qcom-pm8008-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPM) += qcom_rpm-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_RPMH) += qcom-rpmh-regulator.o
 obj-$(CONFIG_REGULATOR_QCOM_SMD_RPM) += qcom_smd-regulator.o
diff --git a/drivers/regulator/qcom-pm8008-regulator.c b/drivers/regulator/qcom-pm8008-regulator.c
new file mode 100644
index 0000000..fdc2f16
--- /dev/null
+++ b/drivers/regulator/qcom-pm8008-regulator.c
@@ -0,0 +1,441 @@ 
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2021, The Linux Foundation. All rights reserved. */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/pm.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/string.h>
+#include <linux/regulator/driver.h>
+#include <linux/regulator/machine.h>
+#include <linux/regulator/of_regulator.h>
+
+#define STARTUP_DELAY_USEC		20
+#define VSET_STEP_MV			8
+#define VSET_STEP_UV			(VSET_STEP_MV * 1000)
+
+#define LDO_ENABLE_REG(base)		(base + 0x46)
+#define ENABLE_BIT			BIT(7)
+
+#define LDO_STATUS1_REG(base)		(base + 0x08)
+#define VREG_READY_BIT			BIT(7)
+
+#define LDO_VSET_LB_REG(base)		(base + 0x40)
+
+#define LDO_STEPPER_CTL_REG(base)	(base + 0x3b)
+#define STEP_RATE_MASK			GENMASK(1, 0)
+
+#define PM8008_MAX_LDO			7
+
+struct regulator_data {
+	char		*name;
+	char		*supply_name;
+	int		min_uv;
+	int		max_uv;
+	int		min_dropout_uv;
+};
+
+struct pm8008_regulator {
+	struct device		*dev;
+	struct regmap		*regmap;
+	struct regulator_desc	rdesc;
+	struct regulator_dev	*rdev;
+	struct device_node	*of_node;
+	u16			base;
+	int			step_rate;
+};
+
+static const struct regulator_data reg_data[PM8008_MAX_LDO] = {
+	/* name  parent      min_uv  max_uv  headroom_uv */
+	{"l1", "vdd_l1_l2",  528000, 1504000, 225000},
+	{"l2", "vdd_l1_l2",  528000, 1504000, 225000},
+	{"l3", "vdd_l3_l4", 1504000, 3400000, 200000},
+	{"l4", "vdd_l3_l4", 1504000, 3400000, 200000},
+	{"l5", "vdd_l5",    1504000, 3400000, 300000},
+	{"l6", "vdd_l6",    1504000, 3400000, 300000},
+	{"l7", "vdd_l7",    1504000, 3400000, 300000},
+};
+
+static int pm8008_read(struct regmap *regmap,  u16 reg, u8 *val, int count)
+{
+	int rc;
+
+	rc = regmap_bulk_read(regmap, reg, val, count);
+	if (rc < 0)
+		pr_err("failed to read %#x, rc=%d\n", reg, rc);
+
+	return rc;
+}
+
+static int pm8008_write(struct regmap *regmap, u16 reg, u8 *val, int count)
+{
+	int rc;
+
+	pr_debug("Writing [%*ph] from address %#x\n", count, val, reg);
+	rc = regmap_bulk_write(regmap, reg, val, count);
+	if (rc < 0)
+		pr_err("failed to write %#x rc=%d\n", reg, rc);
+
+	return rc;
+}
+
+static int pm8008_masked_write(struct regmap *regmap, u16 reg, u8 mask,
+				u8 val)
+{
+	int rc;
+
+	pr_debug("Writing %#x to %#x with mask %#x\n", val, reg, mask);
+	rc = regmap_update_bits(regmap, reg, mask, val);
+	if (rc < 0)
+		pr_err("failed to write %#x to %#x with mask %#x rc=%d\n",
+				val, reg, mask, rc);
+
+	return rc;
+}
+
+static int pm8008_regulator_get_voltage(struct regulator_dev *rdev)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	u8 vset_raw[2];
+	int rc;
+
+	rc = pm8008_read(pm8008_reg->regmap,
+			LDO_VSET_LB_REG(pm8008_reg->base),
+			vset_raw, 2);
+	if (rc < 0) {
+		pr_err("failed to read regulator voltage rc=%d\n", rc);
+		return rc;
+	}
+
+	return (vset_raw[1] << 8 | vset_raw[0]) * 1000;
+}
+
+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);
+}
+
+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;
+
+	current_uv = pm8008_regulator_get_voltage(rdev);
+	if (current_uv < 0) {
+		pr_err("failed to get current voltage rc=%d\n", current_uv);
+		return current_uv;
+	}
+
+	rc = pm8008_masked_write(pm8008_reg->regmap,
+				LDO_ENABLE_REG(pm8008_reg->base),
+				ENABLE_BIT, ENABLE_BIT);
+	if (rc < 0) {
+		pr_err("failed to enable regulator rc=%d\n", rc);
+		return rc;
+	}
+
+	/*
+	 * 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);
+
+	/* Retry 10 times for VREG_READY before bailing out */
+	while (retry_count--) {
+		if (delay_ms > 20)
+			msleep(delay_ms);
+		else
+			usleep_range(delay_us, delay_us + 100);
+
+		rc = pm8008_read(pm8008_reg->regmap,
+				LDO_STATUS1_REG(pm8008_reg->base), &reg, 1);
+		if (rc < 0) {
+			pr_err("failed to read regulator status rc=%d\n", rc);
+			goto disable_ldo;
+		}
+		if (reg & VREG_READY_BIT) {
+			pr_debug("regulator enabled\n");
+			return 0;
+		}
+	}
+
+	pr_err("failed to enable regulator, VREG_READY not set\n");
+	rc = -ETIME;
+
+disable_ldo:
+	pm8008_masked_write(pm8008_reg->regmap,
+			LDO_ENABLE_REG(pm8008_reg->base), ENABLE_BIT, 0);
+
+	return rc;
+}
+
+static int pm8008_regulator_disable(struct regulator_dev *rdev)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	int rc;
+
+	rc = pm8008_masked_write(pm8008_reg->regmap,
+				LDO_ENABLE_REG(pm8008_reg->base),
+				ENABLE_BIT, 0);
+	if (rc < 0) {
+		pr_err("failed to disable regulator rc=%d\n", rc);
+		return rc;
+	}
+
+	pr_debug("regulator disabled\n");
+	return 0;
+}
+
+static int pm8008_write_voltage(struct pm8008_regulator *pm8008_reg, int min_uv,
+				int max_uv)
+{
+	int rc = 0, mv;
+	u8 vset_raw[2];
+
+	mv = DIV_ROUND_UP(min_uv, 1000);
+
+	/*
+	 * Each LSB of regulator is 1mV and the voltage setpoint
+	 * should be multiple of 8mV(step).
+	 */
+	mv = DIV_ROUND_UP(mv, VSET_STEP_MV) * VSET_STEP_MV;
+	if (mv * 1000 > max_uv) {
+		pr_err("requested voltage (%d uV) above maximum limit (%d uV)\n",
+				mv*1000, max_uv);
+		return -EINVAL;
+	}
+
+	vset_raw[0] = mv & 0xff;
+	vset_raw[1] = (mv & 0xff00) >> 8;
+	rc = pm8008_write(pm8008_reg->regmap, LDO_VSET_LB_REG(pm8008_reg->base),
+			vset_raw, 2);
+	if (rc < 0) {
+		pr_err("failed to write voltage rc=%d\n", rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+static int pm8008_regulator_set_voltage_time(struct regulator_dev *rdev,
+				int old_uV, int new_uv)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+
+	return DIV_ROUND_UP(abs(new_uv - old_uV), pm8008_reg->step_rate);
+}
+
+static int pm8008_regulator_set_voltage(struct regulator_dev *rdev,
+				int min_uv, int max_uv, unsigned int *selector)
+{
+	struct pm8008_regulator *pm8008_reg = rdev_get_drvdata(rdev);
+	int rc;
+
+	rc = pm8008_write_voltage(pm8008_reg, min_uv, max_uv);
+	if (rc < 0)
+		return rc;
+
+	*selector = DIV_ROUND_UP(min_uv - pm8008_reg->rdesc.min_uV,
+				VSET_STEP_UV);
+
+	pr_debug("voltage set to %d\n", min_uv);
+	return 0;
+}
+
+static const struct regulator_ops pm8008_regulator_ops = {
+	.enable		= pm8008_regulator_enable,
+	.disable		= pm8008_regulator_disable,
+	.is_enabled		= pm8008_regulator_is_enabled,
+	.set_voltage		= pm8008_regulator_set_voltage,
+	.get_voltage		= pm8008_regulator_get_voltage,
+	.list_voltage		= regulator_list_voltage_linear,
+	.set_voltage_time	= pm8008_regulator_set_voltage_time,
+};
+
+static int pm8008_register_ldo(struct pm8008_regulator *pm8008_reg,
+						const char *name)
+{
+	struct regulator_config reg_config = {};
+	struct regulator_init_data *init_data;
+	struct device *dev = pm8008_reg->dev;
+	struct device_node *reg_node = pm8008_reg->of_node;
+	int rc, i, init_voltage;
+	u32 base = 0;
+	u8 reg;
+
+	/* get regulator data */
+	for (i = 0; i < PM8008_MAX_LDO; i++)
+		if (strstr(name, reg_data[i].name))
+			break;
+
+	if (i == PM8008_MAX_LDO) {
+		dev_err(dev, "Invalid regulator name %s\n", name);
+		return -EINVAL;
+	}
+
+	rc = of_property_read_u32(reg_node, "reg", &base);
+	if (rc < 0) {
+		dev_err(dev, "%s: failed to get regulator base rc=%d\n", name, rc);
+		return rc;
+	}
+	pm8008_reg->base = base;
+
+	init_voltage = -EINVAL;
+	of_property_read_u32(reg_node, "qcom,init-voltage", &init_voltage);
+
+	/* get slew rate */
+	rc = pm8008_read(pm8008_reg->regmap,
+			LDO_STEPPER_CTL_REG(pm8008_reg->base), &reg, 1);
+	if (rc < 0) {
+		dev_err(dev, "%s: failed to read step rate configuration rc=%d\n",
+				name, rc);
+		return rc;
+	}
+	pm8008_reg->step_rate = 38400 >> (reg & STEP_RATE_MASK);
+
+	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;
+	}
+
+	/* configure the initial voltage for the regulator */
+	if (init_voltage > 0) {
+		rc = pm8008_write_voltage(pm8008_reg, init_voltage,
+					init_data->constraints.max_uV);
+		if (rc < 0)
+			dev_err(dev, "%s: failed to set initial voltage rc=%d\n",
+					name, rc);
+	}
+
+	init_data->constraints.input_uV = init_data->constraints.max_uV;
+	init_data->constraints.valid_ops_mask |= REGULATOR_CHANGE_STATUS
+						| REGULATOR_CHANGE_VOLTAGE;
+	reg_config.dev = dev;
+	reg_config.init_data = init_data;
+	reg_config.driver_data = pm8008_reg;
+	reg_config.of_node = reg_node;
+
+	pm8008_reg->rdesc.type = REGULATOR_VOLTAGE;
+	pm8008_reg->rdesc.ops = &pm8008_regulator_ops;
+	pm8008_reg->rdesc.name = init_data->constraints.name;
+	pm8008_reg->rdesc.supply_name = reg_data[i].supply_name;
+	pm8008_reg->rdesc.uV_step = VSET_STEP_UV;
+	pm8008_reg->rdesc.min_uV = reg_data[i].min_uv;
+	pm8008_reg->rdesc.n_voltages
+		= ((reg_data[i].max_uv - reg_data[i].min_uv)
+			/ pm8008_reg->rdesc.uV_step) + 1;
+
+	pm8008_reg->rdesc.min_dropout_uV = reg_data[i].min_dropout_uv;
+	of_property_read_u32(reg_node, "qcom,min-dropout-voltage",
+			     &pm8008_reg->rdesc.min_dropout_uV);
+
+	pm8008_reg->rdev = devm_regulator_register(dev, &pm8008_reg->rdesc,
+						&reg_config);
+	if (IS_ERR(pm8008_reg->rdev)) {
+		rc = PTR_ERR(pm8008_reg->rdev);
+		dev_err(dev, "%s: failed to register regulator rc=%d\n",
+				pm8008_reg->rdesc.name, rc);
+		return rc;
+	}
+
+	pr_debug("%s regulator registered\n", name);
+
+	return 0;
+}
+
+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)
+			return -ENOMEM;
+
+		pm8008_reg->regmap = regmap;
+		pm8008_reg->of_node = child;
+		pm8008_reg->dev = dev;
+
+		rc = of_property_read_string(child, "regulator-name", &name);
+		if (rc)
+			continue;
+
+		rc = pm8008_register_ldo(pm8008_reg, name);
+		if (rc < 0) {
+			dev_err(dev, "failed to register regulator %s rc=%d\n",
+					name, rc);
+			return rc;
+		}
+	}
+
+	return 0;
+}
+
+static int pm8008_regulator_probe(struct platform_device *pdev)
+{
+	int rc = 0;
+	struct regmap *regmap;
+
+	regmap = dev_get_regmap(pdev->dev.parent, NULL);
+	if (!regmap) {
+		dev_err(&pdev->dev, "parent regmap is missing\n");
+		return -EINVAL;
+	}
+
+	rc = pm8008_parse_regulator(regmap, &pdev->dev);
+	if (rc < 0) {
+		dev_err(&pdev->dev, "failed to parse device tree rc=%d\n", rc);
+		return rc;
+	}
+
+	return 0;
+}
+
+static const struct of_device_id pm8008_regulator_match_table[] = {
+	{ .compatible = "qcom,pm8008-regulator", },
+	{ },
+};
+
+static struct platform_driver pm8008_regulator_driver = {
+	.driver	= {
+		.name		= "qcom,pm8008-regulator",
+		.of_match_table	= pm8008_regulator_match_table,
+	},
+	.probe		= pm8008_regulator_probe,
+};
+
+module_platform_driver(pm8008_regulator_driver);
+
+MODULE_DESCRIPTION("Qualcomm PM8008 PMIC Regulator Driver");
+MODULE_LICENSE("GPL v2");