drivers/regulator/pwm-regulator.c - kernel/quantenna - 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/delay.h>
 #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>

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

 	/* Voltage table */
 	struct pwm_voltages *duty_cycle_table;

 	/* regulator descriptor */
 	struct regulator_desc desc;

 	/* Regulator ops */
 	struct regulator_ops ops;

 	int state;

 	/* Continuous voltage */
 	int volt_uV;
 };

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

 /**
  * Voltage table call-backs
  */
 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(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_args pargs;
 	int dutycycle;
 	int ret;

 	pwm_get_args(drvdata->pwm, &pargs);

 	dutycycle = (pargs.period *
 		    drvdata->duty_cycle_table[selector].dutycycle) / 100;

 	ret = pwm_config(drvdata->pwm, dutycycle, pargs.period);
 	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);

 	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);

 	return 0;
 }

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

 	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);

 	return drvdata->volt_uV;
 }

 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
 					int min_uV, int max_uV,
 					unsigned *selector)
 {
 	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
 	unsigned int ramp_delay = rdev->constraints->ramp_delay;
 	struct pwm_args pargs;
 	unsigned int req_diff = min_uV - rdev->constraints->min_uV;
 	unsigned int diff;
 	unsigned int duty_pulse;
 	u64 req_period;
 	u32 rem;
 	int ret;

 	pwm_get_args(drvdata->pwm, &pargs);
 	diff = rdev->constraints->max_uV - rdev->constraints->min_uV;

 	/* First try to find out if we get the iduty cycle time which is
 	 * factor of PWM period time. If (request_diff_to_min * pwm_period)
 	 * is perfect divided by voltage_range_diff then it is possible to
 	 * get duty cycle time which is factor of PWM period. This will help
 	 * to get output voltage nearer to requested value as there is no
 	 * calculation loss.
 	 */
 	req_period = req_diff * pargs.period;
 	div_u64_rem(req_period, diff, &rem);
 	if (!rem) {
 		do_div(req_period, diff);
 		duty_pulse = (unsigned int)req_period;
 	} else {
 		duty_pulse = (pargs.period / 100) * ((req_diff * 100) / diff);
 	}

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

 	ret = pwm_enable(drvdata->pwm);
 	if (ret) {
 		dev_err(&rdev->dev, "Failed to enable PWM: %d\n", ret);
 		return ret;
 	}
 	drvdata->volt_uV = min_uV;

 	/* Delay required by PWM regulator to settle to the new voltage */
 	usleep_range(ramp_delay, ramp_delay + 1000);

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

 	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;
 	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;
 	}

 	/*
 	 * FIXME: pwm_apply_args() should be removed when switching to the
 	 * atomic PWM API.
 	 */
 	pwm_apply_args(drvdata->pwm);

 	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/delay.h>
	#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>

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

	/* Voltage table */
	struct pwm_voltages *duty_cycle_table;

	/* regulator descriptor */
	struct regulator_desc desc;

	/* Regulator ops */
	struct regulator_ops ops;

	int state;

	/* Continuous voltage */
	int volt_uV;
	};

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

	/**
	* Voltage table call-backs
	*/
	static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(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_args pargs;
	int dutycycle;
	int ret;

	pwm_get_args(drvdata->pwm, &pargs);

	dutycycle = (pargs.period *
	drvdata->duty_cycle_table[selector].dutycycle) / 100;

	ret = pwm_config(drvdata->pwm, dutycycle, pargs.period);
	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);

	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);

	return 0;
	}

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

	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);

	return drvdata->volt_uV;
	}

	static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
	int min_uV, int max_uV,
	unsigned *selector)
	{
	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	unsigned int ramp_delay = rdev->constraints->ramp_delay;
	struct pwm_args pargs;
	unsigned int req_diff = min_uV - rdev->constraints->min_uV;
	unsigned int diff;
	unsigned int duty_pulse;
	u64 req_period;
	u32 rem;
	int ret;

	pwm_get_args(drvdata->pwm, &pargs);
	diff = rdev->constraints->max_uV - rdev->constraints->min_uV;

	/* First try to find out if we get the iduty cycle time which is
	* factor of PWM period time. If (request_diff_to_min * pwm_period)
	* is perfect divided by voltage_range_diff then it is possible to
	* get duty cycle time which is factor of PWM period. This will help
	* to get output voltage nearer to requested value as there is no
	* calculation loss.
	*/
	req_period = req_diff * pargs.period;
	div_u64_rem(req_period, diff, &rem);
	if (!rem) {
	do_div(req_period, diff);
	duty_pulse = (unsigned int)req_period;
	} else {
	duty_pulse = (pargs.period / 100) * ((req_diff * 100) / diff);
	}

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

	ret = pwm_enable(drvdata->pwm);
	if (ret) {
	dev_err(&rdev->dev, "Failed to enable PWM: %d\n", ret);
	return ret;
	}
	drvdata->volt_uV = min_uV;

	/* Delay required by PWM regulator to settle to the new voltage */
	usleep_range(ramp_delay, ramp_delay + 1000);

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

	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;
	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;
	}

	/*
	* FIXME: pwm_apply_args() should be removed when switching to the
	* atomic PWM API.
	*/
	pwm_apply_args(drvdata->pwm);

	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");