arch/arm/mach-msm/spm-regulator.c - kernel/msm - Git at Google

 /* Copyright (c) 2013, The Linux Foundation. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 and
  * only version 2 as published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  */

 #define pr_fmt(fmt) "%s: " fmt, __func__

 #include <linux/delay.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/slab.h>
 #include <linux/spmi.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/of_regulator.h>

 #include "spm.h"
 #include "spm-regulator.h"

 #define SPM_REGULATOR_DRIVER_NAME "qcom,spm-regulator"

 struct voltage_range {
 	int min_uV;
 	int set_point_min_uV;
 	int max_uV;
 	int step_uV;
 };

 /* Properties for FTS2 type QPNP PMIC regulators. */

 static const struct voltage_range fts2_range0 = {0, 350000, 1275000,  5000};
 static const struct voltage_range fts2_range1 = {0, 700000, 2040000, 10000};

 #define QPNP_FTS2_REG_TYPE		0x04
 #define QPNP_FTS2_REG_SUBTYPE		0x05
 #define QPNP_FTS2_REG_VOLTAGE_RANGE	0x40
 #define QPNP_FTS2_REG_VOLTAGE_SETPOINT	0x41
 #define QPNP_FTS2_REG_MODE		0x45
 #define QPNP_FTS2_REG_STEP_CTRL		0x61

 #define QPNP_FTS2_TYPE			0x1C
 #define QPNP_FTS2_SUBTYPE		0x08

 #define QPNP_FTS2_MODE_PWM		0x80
 #define QPNP_FTS2_MODE_AUTO		0x40

 #define QPNP_FTS2_STEP_CTRL_STEP_MASK	0x18
 #define QPNP_FTS2_STEP_CTRL_STEP_SHIFT	3
 #define QPNP_FTS2_STEP_CTRL_DELAY_MASK	0x07
 #define QPNP_FTS2_STEP_CTRL_DELAY_SHIFT	0

 /* Clock rate in kHz of the FTS2 regulator reference clock. */
 #define QPNP_FTS2_CLOCK_RATE		19200

 /* Time to delay in us to ensure that a mode change has completed. */
 #define QPNP_FTS2_MODE_CHANGE_DELAY	50

 /* Minimum time in us that it takes to complete a single SPMI write. */
 #define QPNP_SPMI_WRITE_MIN_DELAY	8

 /*
  * The ratio QPNP_FTS2_STEP_MARGIN_NUM/QPNP_FTS2_STEP_MARGIN_DEN is use to
  * adjust the step rate in order to account for oscillator variance.
  */
 #define QPNP_FTS2_STEP_MARGIN_NUM	4
 #define QPNP_FTS2_STEP_MARGIN_DEN	5

 struct spm_vreg {
 	struct regulator_desc		rdesc;
 	struct regulator_dev		*rdev;
 	struct spmi_device		*spmi_dev;
 	const struct voltage_range	*range;
 	int				uV;
 	int				last_set_uV;
 	unsigned			vlevel;
 	unsigned			last_set_vlevel;
 	bool				online;
 	u16				spmi_base_addr;
 	u8				init_mode;
 	int				step_rate;
 };

 static int qpnp_fts2_set_mode(struct spm_vreg *vreg, u8 mode)
 {
 	int rc;

 	rc = spmi_ext_register_writel(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
 		vreg->spmi_base_addr + QPNP_FTS2_REG_MODE, &mode, 1);
 	if (rc)
 		dev_err(&vreg->spmi_dev->dev, "%s: could not write to mode register, rc=%d\n",
 			__func__, rc);

 	return rc;
 }

 static int _spm_regulator_set_voltage(struct regulator_dev *rdev)
 {
 	struct spm_vreg *vreg = rdev_get_drvdata(rdev);
 	int rc;

 	if (vreg->vlevel == vreg->last_set_vlevel)
 		return 0;

 	if (!(vreg->init_mode & QPNP_FTS2_MODE_PWM)
 	    && vreg->uV > vreg->last_set_uV) {
 		/* Switch to PWM mode so that voltage ramping is fast. */
 		rc = qpnp_fts2_set_mode(vreg, QPNP_FTS2_MODE_PWM);
 		if (rc)
 			return rc;
 	}

 	rc = msm_spm_apcs_set_vdd(vreg->vlevel);
 	if (rc) {
 		pr_err("%s: msm_spm_set_vdd failed %d\n", vreg->rdesc.name, rc);
 		return rc;
 	}

 	if (vreg->uV > vreg->last_set_uV) {
 		/* Wait for voltage stepping to complete. */
 		udelay(DIV_ROUND_UP(vreg->uV - vreg->last_set_uV,
 					vreg->step_rate));
 	}

 	if (!(vreg->init_mode & QPNP_FTS2_MODE_PWM)
 	    && vreg->uV > vreg->last_set_uV) {
 		/* Wait for mode transition to complete. */
 		udelay(QPNP_FTS2_MODE_CHANGE_DELAY - QPNP_SPMI_WRITE_MIN_DELAY);
 		/* Switch to AUTO mode so that power consumption is lowered. */
 		rc = qpnp_fts2_set_mode(vreg, QPNP_FTS2_MODE_AUTO);
 		if (rc)
 			return rc;
 	}

 	vreg->last_set_uV = vreg->uV;
 	vreg->last_set_vlevel = vreg->vlevel;

 	return rc;
 }

 static int spm_regulator_set_voltage(struct regulator_dev *rdev, int min_uV,
 					int max_uV, unsigned *selector)
 {
 	struct spm_vreg *vreg = rdev_get_drvdata(rdev);
 	const struct voltage_range *range = vreg->range;
 	int uV = min_uV;
 	unsigned vlevel;

 	if (uV < range->set_point_min_uV && max_uV >= range->set_point_min_uV)
 		uV = range->set_point_min_uV;

 	if (uV < range->set_point_min_uV || uV > range->max_uV) {
 		pr_err("%s: request v=[%d, %d] is outside possible v=[%d, %d]\n",
 			vreg->rdesc.name, min_uV, max_uV,
 			range->set_point_min_uV, range->max_uV);
 		return -EINVAL;
 	}

 	vlevel = DIV_ROUND_UP(uV - range->min_uV, range->step_uV);
 	uV = vlevel * range->step_uV + range->min_uV;

 	if (uV > max_uV) {
 		pr_err("%s: request v=[%d, %d] cannot be met by any set point\n",
 			vreg->rdesc.name, min_uV, max_uV);
 		return -EINVAL;
 	}

 	vreg->vlevel = vlevel;
 	vreg->uV = uV;
 	*selector = vlevel -
 		(vreg->range->set_point_min_uV - vreg->range->min_uV)
 			/ vreg->range->step_uV;

 	if (!vreg->online)
 		return 0;

 	return _spm_regulator_set_voltage(rdev);
 }

 static int spm_regulator_get_voltage(struct regulator_dev *rdev)
 {
 	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

 	return vreg->uV;
 }

 static int spm_regulator_list_voltage(struct regulator_dev *rdev,
 					unsigned selector)
 {
 	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

 	if (selector >= vreg->rdesc.n_voltages)
 		return 0;

 	return selector * vreg->range->step_uV + vreg->range->set_point_min_uV;
 }

 static int spm_regulator_enable(struct regulator_dev *rdev)
 {
 	struct spm_vreg *vreg = rdev_get_drvdata(rdev);
 	int rc;

 	rc = _spm_regulator_set_voltage(rdev);

 	if (!rc)
 		vreg->online = true;

 	return rc;
 }

 static int spm_regulator_disable(struct regulator_dev *rdev)
 {
 	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

 	vreg->online = false;

 	return 0;
 }

 static int spm_regulator_is_enabled(struct regulator_dev *rdev)
 {
 	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

 	return vreg->online;
 }

 static struct regulator_ops spm_regulator_ops = {
 	.get_voltage	= spm_regulator_get_voltage,
 	.set_voltage	= spm_regulator_set_voltage,
 	.list_voltage	= spm_regulator_list_voltage,
 	.enable		= spm_regulator_enable,
 	.disable	= spm_regulator_disable,
 	.is_enabled	= spm_regulator_is_enabled,
 };

 static int qpnp_fts2_check_type(struct spm_vreg *vreg)
 {
 	int rc;
 	u8 type[2];

 	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
 		vreg->spmi_base_addr + QPNP_FTS2_REG_TYPE, type, 2);
 	if (rc) {
 		dev_err(&vreg->spmi_dev->dev, "%s: could not read type register, rc=%d\n",
 			__func__, rc);
 		return rc;
 	}

 	if (type[0] != QPNP_FTS2_TYPE || type[1] != QPNP_FTS2_SUBTYPE) {
 		dev_err(&vreg->spmi_dev->dev, "%s: invalid type=0x%02X or subtype=0x%02X register value\n",
 			__func__, type[0], type[1]);
 		return -ENODEV;
 	}

 	return rc;
 }

 static int qpnp_fts2_init_range(struct spm_vreg *vreg)
 {
 	int rc;
 	u8 reg = 0;

 	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
 		vreg->spmi_base_addr + QPNP_FTS2_REG_VOLTAGE_RANGE, &reg, 1);
 	if (rc) {
 		dev_err(&vreg->spmi_dev->dev, "%s: could not read voltage range register, rc=%d\n",
 			__func__, rc);
 		return rc;
 	}

 	if (reg == 0x00) {
 		vreg->range = &fts2_range0;
 	} else if (reg == 0x01) {
 		vreg->range = &fts2_range1;
 	} else {
 		dev_err(&vreg->spmi_dev->dev, "%s: voltage range=%d is invalid\n",
 			__func__, reg);
 		rc = -EINVAL;
 	}

 	return rc;
 }

 static int qpnp_fts2_init_voltage(struct spm_vreg *vreg)
 {
 	int rc;
 	u8 reg = 0;

 	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
 		vreg->spmi_base_addr + QPNP_FTS2_REG_VOLTAGE_SETPOINT, &reg, 1);
 	if (rc) {
 		dev_err(&vreg->spmi_dev->dev, "%s: could not read voltage setpoint register, rc=%d\n",
 			__func__, rc);
 		return rc;
 	}

 	vreg->vlevel = reg;
 	vreg->uV = vreg->vlevel * vreg->range->step_uV + vreg->range->min_uV;
 	vreg->last_set_uV = vreg->uV;

 	return rc;
 }

 static int qpnp_fts2_init_mode(struct spm_vreg *vreg)
 {
 	int rc;

 	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
 		vreg->spmi_base_addr + QPNP_FTS2_REG_MODE, &vreg->init_mode, 1);
 	if (rc)
 		dev_err(&vreg->spmi_dev->dev, "%s: could not read mode register, rc=%d\n",
 			__func__, rc);

 	return rc;
 }

 static int qpnp_fts2_init_step_rate(struct spm_vreg *vreg)
 {
 	int rc;
 	u8 reg = 0;
 	int step, delay;

 	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
 		vreg->spmi_base_addr + QPNP_FTS2_REG_STEP_CTRL, &reg, 1);
 	if (rc) {
 		dev_err(&vreg->spmi_dev->dev, "%s: could not read stepping control register, rc=%d\n",
 			__func__, rc);
 		return rc;
 	}

 	step = (reg & QPNP_FTS2_STEP_CTRL_STEP_MASK)
 		>> QPNP_FTS2_STEP_CTRL_STEP_SHIFT;
 	delay = (reg & QPNP_FTS2_STEP_CTRL_DELAY_MASK)
 		>> QPNP_FTS2_STEP_CTRL_DELAY_SHIFT;

 	/* step_rate has units of uV/us. */
 	vreg->step_rate = QPNP_FTS2_CLOCK_RATE * vreg->range->step_uV
 				* (1 << step);
 	vreg->step_rate /= 1000 * (8 << delay);
 	vreg->step_rate = vreg->step_rate * QPNP_FTS2_STEP_MARGIN_NUM
 				/ QPNP_FTS2_STEP_MARGIN_DEN;

 	/* Ensure that the stepping rate is greater than 0. */
 	vreg->step_rate = max(vreg->step_rate, 1);

 	return rc;
 }

 static int __devinit spm_regulator_probe(struct spmi_device *spmi)
 {
 	struct device_node *node = spmi->dev.of_node;
 	struct regulator_init_data *init_data;
 	struct spm_vreg *vreg;
 	struct resource *res;
 	int rc;

 	if (!node) {
 		dev_err(&spmi->dev, "%s: device node missing\n", __func__);
 		return -ENODEV;
 	}

 	vreg = devm_kzalloc(&spmi->dev, sizeof(*vreg), GFP_KERNEL);
 	if (!vreg) {
 		pr_err("allocation failed.\n");
 		return -ENOMEM;
 	}
 	vreg->spmi_dev = spmi;

 	res = spmi_get_resource(spmi, NULL, IORESOURCE_MEM, 0);
 	if (!res) {
 		dev_err(&spmi->dev, "%s: node is missing base address\n",
 			__func__);
 		return -EINVAL;
 	}
 	vreg->spmi_base_addr = res->start;

 	rc = qpnp_fts2_check_type(vreg);
 	if (rc)
 		return rc;

 	/*
 	 * The FTS2 regulator must be initialized to range 0 or range 1 during
 	 * PMIC power on sequence.  Once it is set, it cannot be changed
 	 * dynamically.
 	 */
 	rc = qpnp_fts2_init_range(vreg);
 	if (rc)
 		return rc;

 	rc = qpnp_fts2_init_voltage(vreg);
 	if (rc)
 		return rc;

 	rc = qpnp_fts2_init_mode(vreg);
 	if (rc)
 		return rc;

 	rc = qpnp_fts2_init_step_rate(vreg);
 	if (rc)
 		return rc;

 	init_data = of_get_regulator_init_data(&spmi->dev, node);
 	if (!init_data) {
 		dev_err(&spmi->dev, "%s: unable to allocate memory\n",
 				__func__);
 		return -ENOMEM;
 	}
 	init_data->constraints.input_uV = init_data->constraints.max_uV;
 	init_data->constraints.valid_ops_mask |= REGULATOR_CHANGE_STATUS
 						| REGULATOR_CHANGE_VOLTAGE;

 	if (!init_data->constraints.name) {
 		dev_err(&spmi->dev, "%s: node is missing regulator name\n",
 			__func__);
 		return -EINVAL;
 	}

 	vreg->rdesc.name	= init_data->constraints.name;
 	vreg->rdesc.type	= REGULATOR_VOLTAGE;
 	vreg->rdesc.owner	= THIS_MODULE;
 	vreg->rdesc.ops		= &spm_regulator_ops;
 	vreg->rdesc.n_voltages
 		= (vreg->range->max_uV - vreg->range->set_point_min_uV)
 			/ vreg->range->step_uV + 1;

 	vreg->rdev = regulator_register(&vreg->rdesc, &spmi->dev,
 					init_data, vreg, node);
 	if (IS_ERR(vreg->rdev)) {
 		rc = PTR_ERR(vreg->rdev);
 		dev_err(&spmi->dev, "%s: regulator_register failed, rc=%d\n",
 			__func__, rc);
 		return rc;
 	}

 	dev_set_drvdata(&spmi->dev, vreg);

 	pr_info("name=%s, range=%s, voltage=%d uV, mode=%s, step rate=%d uV/us\n",
 		vreg->rdesc.name, vreg->range == &fts2_range0 ? "LV" : "MV",
 		vreg->uV,
 		vreg->init_mode & QPNP_FTS2_MODE_PWM ? "PWM" :
 		    (vreg->init_mode & QPNP_FTS2_MODE_AUTO ? "AUTO" : "PFM"),
 		vreg->step_rate);

 	return rc;
 }

 static int __devexit spm_regulator_remove(struct spmi_device *spmi)
 {
 	struct spm_vreg *vreg = dev_get_drvdata(&spmi->dev);

 	regulator_unregister(vreg->rdev);

 	return 0;
 }

 static struct of_device_id spm_regulator_match_table[] = {
 	{ .compatible = SPM_REGULATOR_DRIVER_NAME, },
 	{}
 };

 static const struct spmi_device_id spm_regulator_id[] = {
 	{ SPM_REGULATOR_DRIVER_NAME, 0 },
 	{}
 };
 MODULE_DEVICE_TABLE(spmi, spm_regulator_id);

 static struct spmi_driver spm_regulator_driver = {
 	.driver = {
 		.name		= SPM_REGULATOR_DRIVER_NAME,
 		.of_match_table = spm_regulator_match_table,
 		.owner		= THIS_MODULE,
 	},
 	.probe		= spm_regulator_probe,
 	.remove		= __devexit_p(spm_regulator_remove),
 	.id_table	= spm_regulator_id,
 };

 /**
  * spm_regulator_init() - register spmi driver for spm-regulator
  *
  * This initialization function should be called in systems in which driver
  * registration ordering must be controlled precisely.
  *
  * Returns 0 on success or errno on failure.
  */
 int __init spm_regulator_init(void)
 {
 	static bool has_registered;

 	if (has_registered)
 		return 0;
 	else
 		has_registered = true;

 	return spmi_driver_register(&spm_regulator_driver);
 }
 EXPORT_SYMBOL(spm_regulator_init);

 static void __exit spm_regulator_exit(void)
 {
 	spmi_driver_unregister(&spm_regulator_driver);
 }

 arch_initcall(spm_regulator_init);
 module_exit(spm_regulator_exit);

 MODULE_LICENSE("GPL v2");
 MODULE_DESCRIPTION("SPM regulator driver");
 MODULE_ALIAS("platform:spm-regulator");
	/* Copyright (c) 2013, The Linux Foundation. All rights reserved.
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 and
	* only version 2 as published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*/

	#define pr_fmt(fmt) "%s: " fmt, __func__

	#include <linux/delay.h>
	#include <linux/err.h>
	#include <linux/init.h>
	#include <linux/kernel.h>
	#include <linux/module.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/slab.h>
	#include <linux/spmi.h>
	#include <linux/regulator/driver.h>
	#include <linux/regulator/machine.h>
	#include <linux/regulator/of_regulator.h>

	#include "spm.h"
	#include "spm-regulator.h"

	#define SPM_REGULATOR_DRIVER_NAME "qcom,spm-regulator"

	struct voltage_range {
	int min_uV;
	int set_point_min_uV;
	int max_uV;
	int step_uV;
	};

	/* Properties for FTS2 type QPNP PMIC regulators. */

	static const struct voltage_range fts2_range0 = {0, 350000, 1275000, 5000};
	static const struct voltage_range fts2_range1 = {0, 700000, 2040000, 10000};

	#define QPNP_FTS2_REG_TYPE 0x04
	#define QPNP_FTS2_REG_SUBTYPE 0x05
	#define QPNP_FTS2_REG_VOLTAGE_RANGE 0x40
	#define QPNP_FTS2_REG_VOLTAGE_SETPOINT 0x41
	#define QPNP_FTS2_REG_MODE 0x45
	#define QPNP_FTS2_REG_STEP_CTRL 0x61

	#define QPNP_FTS2_TYPE 0x1C
	#define QPNP_FTS2_SUBTYPE 0x08

	#define QPNP_FTS2_MODE_PWM 0x80
	#define QPNP_FTS2_MODE_AUTO 0x40

	#define QPNP_FTS2_STEP_CTRL_STEP_MASK 0x18
	#define QPNP_FTS2_STEP_CTRL_STEP_SHIFT 3
	#define QPNP_FTS2_STEP_CTRL_DELAY_MASK 0x07
	#define QPNP_FTS2_STEP_CTRL_DELAY_SHIFT 0

	/* Clock rate in kHz of the FTS2 regulator reference clock. */
	#define QPNP_FTS2_CLOCK_RATE 19200

	/* Time to delay in us to ensure that a mode change has completed. */
	#define QPNP_FTS2_MODE_CHANGE_DELAY 50

	/* Minimum time in us that it takes to complete a single SPMI write. */
	#define QPNP_SPMI_WRITE_MIN_DELAY 8

	/*
	* The ratio QPNP_FTS2_STEP_MARGIN_NUM/QPNP_FTS2_STEP_MARGIN_DEN is use to
	* adjust the step rate in order to account for oscillator variance.
	*/
	#define QPNP_FTS2_STEP_MARGIN_NUM 4
	#define QPNP_FTS2_STEP_MARGIN_DEN 5

	struct spm_vreg {
	struct regulator_desc rdesc;
	struct regulator_dev *rdev;
	struct spmi_device *spmi_dev;
	const struct voltage_range *range;
	int uV;
	int last_set_uV;
	unsigned vlevel;
	unsigned last_set_vlevel;
	bool online;
	u16 spmi_base_addr;
	u8 init_mode;
	int step_rate;
	};

	static int qpnp_fts2_set_mode(struct spm_vreg *vreg, u8 mode)
	{
	int rc;

	rc = spmi_ext_register_writel(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
	vreg->spmi_base_addr + QPNP_FTS2_REG_MODE, &mode, 1);
	if (rc)
	dev_err(&vreg->spmi_dev->dev, "%s: could not write to mode register, rc=%d\n",
	__func__, rc);

	return rc;
	}

	static int _spm_regulator_set_voltage(struct regulator_dev *rdev)
	{
	struct spm_vreg *vreg = rdev_get_drvdata(rdev);
	int rc;

	if (vreg->vlevel == vreg->last_set_vlevel)
	return 0;

	if (!(vreg->init_mode & QPNP_FTS2_MODE_PWM)
	&& vreg->uV > vreg->last_set_uV) {
	/* Switch to PWM mode so that voltage ramping is fast. */
	rc = qpnp_fts2_set_mode(vreg, QPNP_FTS2_MODE_PWM);
	if (rc)
	return rc;
	}

	rc = msm_spm_apcs_set_vdd(vreg->vlevel);
	if (rc) {
	pr_err("%s: msm_spm_set_vdd failed %d\n", vreg->rdesc.name, rc);
	return rc;
	}

	if (vreg->uV > vreg->last_set_uV) {
	/* Wait for voltage stepping to complete. */
	udelay(DIV_ROUND_UP(vreg->uV - vreg->last_set_uV,
	vreg->step_rate));
	}

	if (!(vreg->init_mode & QPNP_FTS2_MODE_PWM)
	&& vreg->uV > vreg->last_set_uV) {
	/* Wait for mode transition to complete. */
	udelay(QPNP_FTS2_MODE_CHANGE_DELAY - QPNP_SPMI_WRITE_MIN_DELAY);
	/* Switch to AUTO mode so that power consumption is lowered. */
	rc = qpnp_fts2_set_mode(vreg, QPNP_FTS2_MODE_AUTO);
	if (rc)
	return rc;
	}

	vreg->last_set_uV = vreg->uV;
	vreg->last_set_vlevel = vreg->vlevel;

	return rc;
	}

	static int spm_regulator_set_voltage(struct regulator_dev *rdev, int min_uV,
	int max_uV, unsigned *selector)
	{
	struct spm_vreg *vreg = rdev_get_drvdata(rdev);
	const struct voltage_range *range = vreg->range;
	int uV = min_uV;
	unsigned vlevel;

	if (uV < range->set_point_min_uV && max_uV >= range->set_point_min_uV)
	uV = range->set_point_min_uV;

	if (uV < range->set_point_min_uV \|\| uV > range->max_uV) {
	pr_err("%s: request v=[%d, %d] is outside possible v=[%d, %d]\n",
	vreg->rdesc.name, min_uV, max_uV,
	range->set_point_min_uV, range->max_uV);
	return -EINVAL;
	}

	vlevel = DIV_ROUND_UP(uV - range->min_uV, range->step_uV);
	uV = vlevel * range->step_uV + range->min_uV;

	if (uV > max_uV) {
	pr_err("%s: request v=[%d, %d] cannot be met by any set point\n",
	vreg->rdesc.name, min_uV, max_uV);
	return -EINVAL;
	}

	vreg->vlevel = vlevel;
	vreg->uV = uV;
	*selector = vlevel -
	(vreg->range->set_point_min_uV - vreg->range->min_uV)
	/ vreg->range->step_uV;

	if (!vreg->online)
	return 0;

	return _spm_regulator_set_voltage(rdev);
	}

	static int spm_regulator_get_voltage(struct regulator_dev *rdev)
	{
	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

	return vreg->uV;
	}

	static int spm_regulator_list_voltage(struct regulator_dev *rdev,
	unsigned selector)
	{
	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

	if (selector >= vreg->rdesc.n_voltages)
	return 0;

	return selector * vreg->range->step_uV + vreg->range->set_point_min_uV;
	}

	static int spm_regulator_enable(struct regulator_dev *rdev)
	{
	struct spm_vreg *vreg = rdev_get_drvdata(rdev);
	int rc;

	rc = _spm_regulator_set_voltage(rdev);

	if (!rc)
	vreg->online = true;

	return rc;
	}

	static int spm_regulator_disable(struct regulator_dev *rdev)
	{
	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

	vreg->online = false;

	return 0;
	}

	static int spm_regulator_is_enabled(struct regulator_dev *rdev)
	{
	struct spm_vreg *vreg = rdev_get_drvdata(rdev);

	return vreg->online;
	}

	static struct regulator_ops spm_regulator_ops = {
	.get_voltage = spm_regulator_get_voltage,
	.set_voltage = spm_regulator_set_voltage,
	.list_voltage = spm_regulator_list_voltage,
	.enable = spm_regulator_enable,
	.disable = spm_regulator_disable,
	.is_enabled = spm_regulator_is_enabled,
	};

	static int qpnp_fts2_check_type(struct spm_vreg *vreg)
	{
	int rc;
	u8 type[2];

	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
	vreg->spmi_base_addr + QPNP_FTS2_REG_TYPE, type, 2);
	if (rc) {
	dev_err(&vreg->spmi_dev->dev, "%s: could not read type register, rc=%d\n",
	__func__, rc);
	return rc;
	}

	if (type[0] != QPNP_FTS2_TYPE \|\| type[1] != QPNP_FTS2_SUBTYPE) {
	dev_err(&vreg->spmi_dev->dev, "%s: invalid type=0x%02X or subtype=0x%02X register value\n",
	__func__, type[0], type[1]);
	return -ENODEV;
	}

	return rc;
	}

	static int qpnp_fts2_init_range(struct spm_vreg *vreg)
	{
	int rc;
	u8 reg = 0;

	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
	vreg->spmi_base_addr + QPNP_FTS2_REG_VOLTAGE_RANGE, &reg, 1);
	if (rc) {
	dev_err(&vreg->spmi_dev->dev, "%s: could not read voltage range register, rc=%d\n",
	__func__, rc);
	return rc;
	}

	if (reg == 0x00) {
	vreg->range = &fts2_range0;
	} else if (reg == 0x01) {
	vreg->range = &fts2_range1;
	} else {
	dev_err(&vreg->spmi_dev->dev, "%s: voltage range=%d is invalid\n",
	__func__, reg);
	rc = -EINVAL;
	}

	return rc;
	}

	static int qpnp_fts2_init_voltage(struct spm_vreg *vreg)
	{
	int rc;
	u8 reg = 0;

	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
	vreg->spmi_base_addr + QPNP_FTS2_REG_VOLTAGE_SETPOINT, &reg, 1);
	if (rc) {
	dev_err(&vreg->spmi_dev->dev, "%s: could not read voltage setpoint register, rc=%d\n",
	__func__, rc);
	return rc;
	}

	vreg->vlevel = reg;
	vreg->uV = vreg->vlevel * vreg->range->step_uV + vreg->range->min_uV;
	vreg->last_set_uV = vreg->uV;

	return rc;
	}

	static int qpnp_fts2_init_mode(struct spm_vreg *vreg)
	{
	int rc;

	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
	vreg->spmi_base_addr + QPNP_FTS2_REG_MODE, &vreg->init_mode, 1);
	if (rc)
	dev_err(&vreg->spmi_dev->dev, "%s: could not read mode register, rc=%d\n",
	__func__, rc);

	return rc;
	}

	static int qpnp_fts2_init_step_rate(struct spm_vreg *vreg)
	{
	int rc;
	u8 reg = 0;
	int step, delay;

	rc = spmi_ext_register_readl(vreg->spmi_dev->ctrl, vreg->spmi_dev->sid,
	vreg->spmi_base_addr + QPNP_FTS2_REG_STEP_CTRL, &reg, 1);
	if (rc) {
	dev_err(&vreg->spmi_dev->dev, "%s: could not read stepping control register, rc=%d\n",
	__func__, rc);
	return rc;
	}

	step = (reg & QPNP_FTS2_STEP_CTRL_STEP_MASK)
	>> QPNP_FTS2_STEP_CTRL_STEP_SHIFT;
	delay = (reg & QPNP_FTS2_STEP_CTRL_DELAY_MASK)
	>> QPNP_FTS2_STEP_CTRL_DELAY_SHIFT;

	/* step_rate has units of uV/us. */
	vreg->step_rate = QPNP_FTS2_CLOCK_RATE * vreg->range->step_uV
	* (1 << step);
	vreg->step_rate /= 1000 * (8 << delay);
	vreg->step_rate = vreg->step_rate * QPNP_FTS2_STEP_MARGIN_NUM
	/ QPNP_FTS2_STEP_MARGIN_DEN;

	/* Ensure that the stepping rate is greater than 0. */
	vreg->step_rate = max(vreg->step_rate, 1);

	return rc;
	}

	static int __devinit spm_regulator_probe(struct spmi_device *spmi)
	{
	struct device_node *node = spmi->dev.of_node;
	struct regulator_init_data *init_data;
	struct spm_vreg *vreg;
	struct resource *res;
	int rc;

	if (!node) {
	dev_err(&spmi->dev, "%s: device node missing\n", __func__);
	return -ENODEV;
	}

	vreg = devm_kzalloc(&spmi->dev, sizeof(*vreg), GFP_KERNEL);
	if (!vreg) {
	pr_err("allocation failed.\n");
	return -ENOMEM;
	}
	vreg->spmi_dev = spmi;

	res = spmi_get_resource(spmi, NULL, IORESOURCE_MEM, 0);
	if (!res) {
	dev_err(&spmi->dev, "%s: node is missing base address\n",
	__func__);
	return -EINVAL;
	}
	vreg->spmi_base_addr = res->start;

	rc = qpnp_fts2_check_type(vreg);
	if (rc)
	return rc;

	/*
	* The FTS2 regulator must be initialized to range 0 or range 1 during
	* PMIC power on sequence. Once it is set, it cannot be changed
	* dynamically.
	*/
	rc = qpnp_fts2_init_range(vreg);
	if (rc)
	return rc;

	rc = qpnp_fts2_init_voltage(vreg);
	if (rc)
	return rc;

	rc = qpnp_fts2_init_mode(vreg);
	if (rc)
	return rc;

	rc = qpnp_fts2_init_step_rate(vreg);
	if (rc)
	return rc;

	init_data = of_get_regulator_init_data(&spmi->dev, node);
	if (!init_data) {
	dev_err(&spmi->dev, "%s: unable to allocate memory\n",
	__func__);
	return -ENOMEM;
	}
	init_data->constraints.input_uV = init_data->constraints.max_uV;
	init_data->constraints.valid_ops_mask \|= REGULATOR_CHANGE_STATUS
	\| REGULATOR_CHANGE_VOLTAGE;

	if (!init_data->constraints.name) {
	dev_err(&spmi->dev, "%s: node is missing regulator name\n",
	__func__);
	return -EINVAL;
	}

	vreg->rdesc.name = init_data->constraints.name;
	vreg->rdesc.type = REGULATOR_VOLTAGE;
	vreg->rdesc.owner = THIS_MODULE;
	vreg->rdesc.ops = &spm_regulator_ops;
	vreg->rdesc.n_voltages
	= (vreg->range->max_uV - vreg->range->set_point_min_uV)
	/ vreg->range->step_uV + 1;

	vreg->rdev = regulator_register(&vreg->rdesc, &spmi->dev,
	init_data, vreg, node);
	if (IS_ERR(vreg->rdev)) {
	rc = PTR_ERR(vreg->rdev);
	dev_err(&spmi->dev, "%s: regulator_register failed, rc=%d\n",
	__func__, rc);
	return rc;
	}

	dev_set_drvdata(&spmi->dev, vreg);

	pr_info("name=%s, range=%s, voltage=%d uV, mode=%s, step rate=%d uV/us\n",
	vreg->rdesc.name, vreg->range == &fts2_range0 ? "LV" : "MV",
	vreg->uV,
	vreg->init_mode & QPNP_FTS2_MODE_PWM ? "PWM" :
	(vreg->init_mode & QPNP_FTS2_MODE_AUTO ? "AUTO" : "PFM"),
	vreg->step_rate);

	return rc;
	}

	static int __devexit spm_regulator_remove(struct spmi_device *spmi)
	{
	struct spm_vreg *vreg = dev_get_drvdata(&spmi->dev);

	regulator_unregister(vreg->rdev);

	return 0;
	}

	static struct of_device_id spm_regulator_match_table[] = {
	{ .compatible = SPM_REGULATOR_DRIVER_NAME, },
	{}
	};

	static const struct spmi_device_id spm_regulator_id[] = {
	{ SPM_REGULATOR_DRIVER_NAME, 0 },
	{}
	};
	MODULE_DEVICE_TABLE(spmi, spm_regulator_id);

	static struct spmi_driver spm_regulator_driver = {
	.driver = {
	.name = SPM_REGULATOR_DRIVER_NAME,
	.of_match_table = spm_regulator_match_table,
	.owner = THIS_MODULE,
	},
	.probe = spm_regulator_probe,
	.remove = __devexit_p(spm_regulator_remove),
	.id_table = spm_regulator_id,
	};

	/**
	* spm_regulator_init() - register spmi driver for spm-regulator
	*
	* This initialization function should be called in systems in which driver
	* registration ordering must be controlled precisely.
	*
	* Returns 0 on success or errno on failure.
	*/
	int __init spm_regulator_init(void)
	{
	static bool has_registered;

	if (has_registered)
	return 0;
	else
	has_registered = true;

	return spmi_driver_register(&spm_regulator_driver);
	}
	EXPORT_SYMBOL(spm_regulator_init);

	static void __exit spm_regulator_exit(void)
	{
	spmi_driver_unregister(&spm_regulator_driver);
	}

	arch_initcall(spm_regulator_init);
	module_exit(spm_regulator_exit);

	MODULE_LICENSE("GPL v2");
	MODULE_DESCRIPTION("SPM regulator driver");
	MODULE_ALIAS("platform:spm-regulator");