drivers/regulator/pwm-regulator.c - linux - Git at Google

 /*
  * Regulator driver for PWM Regulators
  *
  * Copyright (C) 2014 - STMicroelectronics Inc.
  *
  * Author: Lee Jones <lee.jones@linaro.org>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  */

 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/err.h>
 #include <linux/regulator/driver.h>
 #include <linux/regulator/machine.h>
 #include <linux/regulator/of_regulator.h>
 #include <linux/of.h>
 #include <linux/of_device.h>
 #include <linux/pwm.h>
 #include <linux/gpio/consumer.h>

 struct pwm_continuous_reg_data {
 	unsigned int min_uV_dutycycle;
 	unsigned int max_uV_dutycycle;
 	unsigned int dutycycle_unit;
 };

 struct pwm_regulator_data {
 	/*  Shared */
 	struct pwm_device *pwm;

 	/* Voltage table */
 	struct pwm_voltages *duty_cycle_table;

 	/* Continuous mode info */
 	struct pwm_continuous_reg_data continuous;

 	/* regulator descriptor */
 	struct regulator_desc desc;

 	/* Regulator ops */
 	struct regulator_ops ops;

 	int state;

 	/* Enable GPIO */
 	struct gpio_desc *enb_gpio;
 };

 struct pwm_voltages {
 	unsigned int uV;
 	unsigned int dutycycle;
 };

 /**
  * Voltage table call-backs
  */
 static void pwm_regulator_init_state(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 	struct pwm_state pwm_state;
 	unsigned int dutycycle;
 	int i;

 	pwm_get_state(drvdata->pwm, &pwm_state);
 	dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);

 	for (i = 0; i < rdev->desc->n_voltages; i++) {
 		if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
 			drvdata->state = i;
 			return;
 		}
 	}
 }

 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);

 	if (drvdata->state < 0)
 		pwm_regulator_init_state(rdev);

 	return drvdata->state;
 }

 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
 					 unsigned selector)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 	struct pwm_state pstate;
 	int ret;

 	pwm_init_state(drvdata->pwm, &pstate);
 	pwm_set_relative_duty_cycle(&pstate,
 			drvdata->duty_cycle_table[selector].dutycycle, 100);

 	ret = pwm_apply_state(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
 	}

 	drvdata->state = selector;

 	return 0;
 }

 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
 				      unsigned selector)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);

 	if (selector >= rdev->desc->n_voltages)
 		return -EINVAL;

 	return drvdata->duty_cycle_table[selector].uV;
 }

 static int pwm_regulator_enable(struct regulator_dev *dev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

 	gpiod_set_value_cansleep(drvdata->enb_gpio, 1);

 	return pwm_enable(drvdata->pwm);
 }

 static int pwm_regulator_disable(struct regulator_dev *dev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

 	pwm_disable(drvdata->pwm);

 	gpiod_set_value_cansleep(drvdata->enb_gpio, 0);

 	return 0;
 }

 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

 	if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
 		return false;

 	return pwm_is_enabled(drvdata->pwm);
 }

 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 	int min_uV = rdev->constraints->min_uV;
 	int max_uV = rdev->constraints->max_uV;
 	int diff_uV = max_uV - min_uV;
 	struct pwm_state pstate;
 	unsigned int diff_duty;
 	unsigned int voltage;

 	pwm_get_state(drvdata->pwm, &pstate);

 	voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);

 	/*
 	 * The dutycycle for min_uV might be greater than the one for max_uV.
 	 * This is happening when the user needs an inversed polarity, but the
 	 * PWM device does not support inversing it in hardware.
 	 */
 	if (max_uV_duty < min_uV_duty) {
 		voltage = min_uV_duty - voltage;
 		diff_duty = min_uV_duty - max_uV_duty;
 	} else {
 		voltage = voltage - min_uV_duty;
 		diff_duty = max_uV_duty - min_uV_duty;
 	}

 	voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);

 	return voltage + min_uV;
 }

 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 				     int req_min_uV, int req_max_uV,
 				     unsigned int *selector)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
 	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
 	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
 	int min_uV = rdev->constraints->min_uV;
 	int max_uV = rdev->constraints->max_uV;
 	int diff_uV = max_uV - min_uV;
 	struct pwm_state pstate;
 	unsigned int diff_duty;
 	unsigned int dutycycle;
 	int ret;

 	pwm_init_state(drvdata->pwm, &pstate);

 	/*
 	 * The dutycycle for min_uV might be greater than the one for max_uV.
 	 * This is happening when the user needs an inversed polarity, but the
 	 * PWM device does not support inversing it in hardware.
 	 */
 	if (max_uV_duty < min_uV_duty)
 		diff_duty = min_uV_duty - max_uV_duty;
 	else
 		diff_duty = max_uV_duty - min_uV_duty;

 	dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
 					  diff_duty,
 					  diff_uV);

 	if (max_uV_duty < min_uV_duty)
 		dutycycle = min_uV_duty - dutycycle;
 	else
 		dutycycle = min_uV_duty + dutycycle;

 	pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);

 	ret = pwm_apply_state(drvdata->pwm, &pstate);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
 		return ret;
 	}

 	return 0;
 }

 static struct regulator_ops pwm_regulator_voltage_table_ops = {
 	.set_voltage_sel = pwm_regulator_set_voltage_sel,
 	.get_voltage_sel = pwm_regulator_get_voltage_sel,
 	.list_voltage    = pwm_regulator_list_voltage,
 	.map_voltage     = regulator_map_voltage_iterate,
 	.enable          = pwm_regulator_enable,
 	.disable         = pwm_regulator_disable,
 	.is_enabled      = pwm_regulator_is_enabled,
 };

 static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
 	.get_voltage = pwm_regulator_get_voltage,
 	.set_voltage = pwm_regulator_set_voltage,
 	.enable          = pwm_regulator_enable,
 	.disable         = pwm_regulator_disable,
 	.is_enabled      = pwm_regulator_is_enabled,
 };

 static struct regulator_desc pwm_regulator_desc = {
 	.name		= "pwm-regulator",
 	.type		= REGULATOR_VOLTAGE,
 	.owner		= THIS_MODULE,
 	.supply_name    = "pwm",
 };

 static int pwm_regulator_init_table(struct platform_device *pdev,
 				    struct pwm_regulator_data *drvdata)
 {
 	struct device_node *np = pdev->dev.of_node;
 	struct pwm_voltages *duty_cycle_table;
 	unsigned int length = 0;
 	int ret;

 	of_find_property(np, "voltage-table", &length);

 	if ((length < sizeof(*duty_cycle_table)) ||
 	    (length % sizeof(*duty_cycle_table))) {
 		dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
 			length);
 		return -EINVAL;
 	}

 	duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
 	if (!duty_cycle_table)
 		return -ENOMEM;

 	ret = of_property_read_u32_array(np, "voltage-table",
 					 (u32 *)duty_cycle_table,
 					 length / sizeof(u32));
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
 		return ret;
 	}

 	drvdata->state			= -EINVAL;
 	drvdata->duty_cycle_table	= duty_cycle_table;
 	memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
 	       sizeof(drvdata->ops));
 	drvdata->desc.ops = &drvdata->ops;
 	drvdata->desc.n_voltages	= length / sizeof(*duty_cycle_table);

 	return 0;
 }

 static int pwm_regulator_init_continuous(struct platform_device *pdev,
 					 struct pwm_regulator_data *drvdata)
 {
 	u32 dutycycle_range[2] = { 0, 100 };
 	u32 dutycycle_unit = 100;

 	memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
 	       sizeof(drvdata->ops));
 	drvdata->desc.ops = &drvdata->ops;
 	drvdata->desc.continuous_voltage_range = true;

 	of_property_read_u32_array(pdev->dev.of_node,
 				   "pwm-dutycycle-range",
 				   dutycycle_range, 2);
 	of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
 			     &dutycycle_unit);

 	if (dutycycle_range[0] > dutycycle_unit ||
 	    dutycycle_range[1] > dutycycle_unit)
 		return -EINVAL;

 	drvdata->continuous.dutycycle_unit = dutycycle_unit;
 	drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
 	drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];

 	return 0;
 }

 static int pwm_regulator_probe(struct platform_device *pdev)
 {
 	const struct regulator_init_data *init_data;
 	struct pwm_regulator_data *drvdata;
 	struct regulator_dev *regulator;
 	struct regulator_config config = { };
 	struct device_node *np = pdev->dev.of_node;
 	enum gpiod_flags gpio_flags;
 	int ret;

 	if (!np) {
 		dev_err(&pdev->dev, "Device Tree node missing\n");
 		return -EINVAL;
 	}

 	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
 	if (!drvdata)
 		return -ENOMEM;

 	memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));

 	if (of_find_property(np, "voltage-table", NULL))
 		ret = pwm_regulator_init_table(pdev, drvdata);
 	else
 		ret = pwm_regulator_init_continuous(pdev, drvdata);
 	if (ret)
 		return ret;

 	init_data = of_get_regulator_init_data(&pdev->dev, np,
 					       &drvdata->desc);
 	if (!init_data)
 		return -ENOMEM;

 	config.of_node = np;
 	config.dev = &pdev->dev;
 	config.driver_data = drvdata;
 	config.init_data = init_data;

 	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
 	if (IS_ERR(drvdata->pwm)) {
 		ret = PTR_ERR(drvdata->pwm);
 		dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
 		return ret;
 	}

 	if (init_data->constraints.boot_on || init_data->constraints.always_on)
 		gpio_flags = GPIOD_OUT_HIGH;
 	else
 		gpio_flags = GPIOD_OUT_LOW;
 	drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
 						    gpio_flags);
 	if (IS_ERR(drvdata->enb_gpio)) {
 		ret = PTR_ERR(drvdata->enb_gpio);
 		dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
 		return ret;
 	}

 	ret = pwm_adjust_config(drvdata->pwm);
 	if (ret)
 		return ret;

 	regulator = devm_regulator_register(&pdev->dev,
 					    &drvdata->desc, &config);
 	if (IS_ERR(regulator)) {
 		ret = PTR_ERR(regulator);
 		dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
 			drvdata->desc.name, ret);
 		return ret;
 	}

 	return 0;
 }

 static const struct of_device_id pwm_of_match[] = {
 	{ .compatible = "pwm-regulator" },
 	{ },
 };
 MODULE_DEVICE_TABLE(of, pwm_of_match);

 static struct platform_driver pwm_regulator_driver = {
 	.driver = {
 		.name		= "pwm-regulator",
 		.of_match_table = of_match_ptr(pwm_of_match),
 	},
 	.probe = pwm_regulator_probe,
 };

 module_platform_driver(pwm_regulator_driver);

 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
 MODULE_DESCRIPTION("PWM Regulator Driver");
 MODULE_ALIAS("platform:pwm-regulator");
	/*
	* Regulator driver for PWM Regulators
	*
	* Copyright (C) 2014 - STMicroelectronics Inc.
	*
	* Author: Lee Jones <lee.jones@linaro.org>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*/

	#include <linux/module.h>
	#include <linux/init.h>
	#include <linux/err.h>
	#include <linux/regulator/driver.h>
	#include <linux/regulator/machine.h>
	#include <linux/regulator/of_regulator.h>
	#include <linux/of.h>
	#include <linux/of_device.h>
	#include <linux/pwm.h>
	#include <linux/gpio/consumer.h>

	struct pwm_continuous_reg_data {
	unsigned int min_uV_dutycycle;
	unsigned int max_uV_dutycycle;
	unsigned int dutycycle_unit;
	};

	struct pwm_regulator_data {
	/* Shared */
	struct pwm_device *pwm;

	/* Voltage table */
	struct pwm_voltages *duty_cycle_table;

	/* Continuous mode info */
	struct pwm_continuous_reg_data continuous;

	/* regulator descriptor */
	struct regulator_desc desc;

	/* Regulator ops */
	struct regulator_ops ops;

	int state;

	/* Enable GPIO */
	struct gpio_desc *enb_gpio;
	};

	struct pwm_voltages {
	unsigned int uV;
	unsigned int dutycycle;
	};

	/**
	* Voltage table call-backs
	*/
	static void pwm_regulator_init_state(struct regulator_dev *rdev)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	struct pwm_state pwm_state;
	unsigned int dutycycle;
	int i;

	pwm_get_state(drvdata->pwm, &pwm_state);
	dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);

	for (i = 0; i < rdev->desc->n_voltages; i++) {
	if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
	drvdata->state = i;
	return;
	}
	}
	}

	static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);

	if (drvdata->state < 0)
	pwm_regulator_init_state(rdev);

	return drvdata->state;
	}

	static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
	unsigned selector)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	struct pwm_state pstate;
	int ret;

	pwm_init_state(drvdata->pwm, &pstate);
	pwm_set_relative_duty_cycle(&pstate,
	drvdata->duty_cycle_table[selector].dutycycle, 100);

	ret = pwm_apply_state(drvdata->pwm, &pstate);
	if (ret) {
	dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
	return ret;
	}

	drvdata->state = selector;

	return 0;
	}

	static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
	unsigned selector)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);

	if (selector >= rdev->desc->n_voltages)
	return -EINVAL;

	return drvdata->duty_cycle_table[selector].uV;
	}

	static int pwm_regulator_enable(struct regulator_dev *dev)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

	gpiod_set_value_cansleep(drvdata->enb_gpio, 1);

	return pwm_enable(drvdata->pwm);
	}

	static int pwm_regulator_disable(struct regulator_dev *dev)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

	pwm_disable(drvdata->pwm);

	gpiod_set_value_cansleep(drvdata->enb_gpio, 0);

	return 0;
	}

	static int pwm_regulator_is_enabled(struct regulator_dev *dev)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);

	if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
	return false;

	return pwm_is_enabled(drvdata->pwm);
	}

	static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
	int min_uV = rdev->constraints->min_uV;
	int max_uV = rdev->constraints->max_uV;
	int diff_uV = max_uV - min_uV;
	struct pwm_state pstate;
	unsigned int diff_duty;
	unsigned int voltage;

	pwm_get_state(drvdata->pwm, &pstate);

	voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);

	/*
	* The dutycycle for min_uV might be greater than the one for max_uV.
	* This is happening when the user needs an inversed polarity, but the
	* PWM device does not support inversing it in hardware.
	*/
	if (max_uV_duty < min_uV_duty) {
	voltage = min_uV_duty - voltage;
	diff_duty = min_uV_duty - max_uV_duty;
	} else {
	voltage = voltage - min_uV_duty;
	diff_duty = max_uV_duty - min_uV_duty;
	}

	voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);

	return voltage + min_uV;
	}

	static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
	int req_min_uV, int req_max_uV,
	unsigned int *selector)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
	unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
	unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
	int min_uV = rdev->constraints->min_uV;
	int max_uV = rdev->constraints->max_uV;
	int diff_uV = max_uV - min_uV;
	struct pwm_state pstate;
	unsigned int diff_duty;
	unsigned int dutycycle;
	int ret;

	pwm_init_state(drvdata->pwm, &pstate);

	/*
	* The dutycycle for min_uV might be greater than the one for max_uV.
	* This is happening when the user needs an inversed polarity, but the
	* PWM device does not support inversing it in hardware.
	*/
	if (max_uV_duty < min_uV_duty)
	diff_duty = min_uV_duty - max_uV_duty;
	else
	diff_duty = max_uV_duty - min_uV_duty;

	dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
	diff_duty,
	diff_uV);

	if (max_uV_duty < min_uV_duty)
	dutycycle = min_uV_duty - dutycycle;
	else
	dutycycle = min_uV_duty + dutycycle;

	pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);

	ret = pwm_apply_state(drvdata->pwm, &pstate);
	if (ret) {
	dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
	return ret;
	}

	return 0;
	}

	static struct regulator_ops pwm_regulator_voltage_table_ops = {
	.set_voltage_sel = pwm_regulator_set_voltage_sel,
	.get_voltage_sel = pwm_regulator_get_voltage_sel,
	.list_voltage = pwm_regulator_list_voltage,
	.map_voltage = regulator_map_voltage_iterate,
	.enable = pwm_regulator_enable,
	.disable = pwm_regulator_disable,
	.is_enabled = pwm_regulator_is_enabled,
	};

	static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
	.get_voltage = pwm_regulator_get_voltage,
	.set_voltage = pwm_regulator_set_voltage,
	.enable = pwm_regulator_enable,
	.disable = pwm_regulator_disable,
	.is_enabled = pwm_regulator_is_enabled,
	};

	static struct regulator_desc pwm_regulator_desc = {
	.name = "pwm-regulator",
	.type = REGULATOR_VOLTAGE,
	.owner = THIS_MODULE,
	.supply_name = "pwm",
	};

	static int pwm_regulator_init_table(struct platform_device *pdev,
	struct pwm_regulator_data *drvdata)
	{
	struct device_node *np = pdev->dev.of_node;
	struct pwm_voltages *duty_cycle_table;
	unsigned int length = 0;
	int ret;

	of_find_property(np, "voltage-table", &length);

	if ((length < sizeof(*duty_cycle_table)) \|\|
	(length % sizeof(*duty_cycle_table))) {
	dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
	length);
	return -EINVAL;
	}

	duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
	if (!duty_cycle_table)
	return -ENOMEM;

	ret = of_property_read_u32_array(np, "voltage-table",
	(u32 *)duty_cycle_table,
	length / sizeof(u32));
	if (ret) {
	dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
	return ret;
	}

	drvdata->state = -EINVAL;
	drvdata->duty_cycle_table = duty_cycle_table;
	memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
	sizeof(drvdata->ops));
	drvdata->desc.ops = &drvdata->ops;
	drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);

	return 0;
	}

	static int pwm_regulator_init_continuous(struct platform_device *pdev,
	struct pwm_regulator_data *drvdata)
	{
	u32 dutycycle_range[2] = { 0, 100 };
	u32 dutycycle_unit = 100;

	memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
	sizeof(drvdata->ops));
	drvdata->desc.ops = &drvdata->ops;
	drvdata->desc.continuous_voltage_range = true;

	of_property_read_u32_array(pdev->dev.of_node,
	"pwm-dutycycle-range",
	dutycycle_range, 2);
	of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
	&dutycycle_unit);

	if (dutycycle_range[0] > dutycycle_unit \|\|
	dutycycle_range[1] > dutycycle_unit)
	return -EINVAL;

	drvdata->continuous.dutycycle_unit = dutycycle_unit;
	drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
	drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];

	return 0;
	}

	static int pwm_regulator_probe(struct platform_device *pdev)
	{
	const struct regulator_init_data *init_data;
	struct pwm_regulator_data *drvdata;
	struct regulator_dev *regulator;
	struct regulator_config config = { };
	struct device_node *np = pdev->dev.of_node;
	enum gpiod_flags gpio_flags;
	int ret;

	if (!np) {
	dev_err(&pdev->dev, "Device Tree node missing\n");
	return -EINVAL;
	}

	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
	if (!drvdata)
	return -ENOMEM;

	memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));

	if (of_find_property(np, "voltage-table", NULL))
	ret = pwm_regulator_init_table(pdev, drvdata);
	else
	ret = pwm_regulator_init_continuous(pdev, drvdata);
	if (ret)
	return ret;

	init_data = of_get_regulator_init_data(&pdev->dev, np,
	&drvdata->desc);
	if (!init_data)
	return -ENOMEM;

	config.of_node = np;
	config.dev = &pdev->dev;
	config.driver_data = drvdata;
	config.init_data = init_data;

	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
	if (IS_ERR(drvdata->pwm)) {
	ret = PTR_ERR(drvdata->pwm);
	dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
	return ret;
	}

	if (init_data->constraints.boot_on \|\| init_data->constraints.always_on)
	gpio_flags = GPIOD_OUT_HIGH;
	else
	gpio_flags = GPIOD_OUT_LOW;
	drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
	gpio_flags);
	if (IS_ERR(drvdata->enb_gpio)) {
	ret = PTR_ERR(drvdata->enb_gpio);
	dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
	return ret;
	}

	ret = pwm_adjust_config(drvdata->pwm);
	if (ret)
	return ret;

	regulator = devm_regulator_register(&pdev->dev,
	&drvdata->desc, &config);
	if (IS_ERR(regulator)) {
	ret = PTR_ERR(regulator);
	dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
	drvdata->desc.name, ret);
	return ret;
	}

	return 0;
	}

	static const struct of_device_id pwm_of_match[] = {
	{ .compatible = "pwm-regulator" },
	{ },
	};
	MODULE_DEVICE_TABLE(of, pwm_of_match);

	static struct platform_driver pwm_regulator_driver = {
	.driver = {
	.name = "pwm-regulator",
	.of_match_table = of_match_ptr(pwm_of_match),
	},
	.probe = pwm_regulator_probe,
	};

	module_platform_driver(pwm_regulator_driver);

	MODULE_LICENSE("GPL");
	MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
	MODULE_DESCRIPTION("PWM Regulator Driver");
	MODULE_ALIAS("platform:pwm-regulator");