[deliverable/linux.git] / drivers / regulator / pwm-regulator.c

/*
 * 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;
	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);
	unsigned int pwm_reg_period;
	int dutycycle;
	int ret;

	pwm_reg_period = pwm_get_period(drvdata->pwm);

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

	ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
	if (ret) {
		dev_err(&rdev->dev, "Failed to configure PWM\n");
		return ret;
	}

	drvdata->state = selector;

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

	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;
}

/**
 * Continuous voltage call-backs
 */
static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV)
{
	int min_uV = rdev->constraints->min_uV;
	int max_uV = rdev->constraints->max_uV;
	int diff = max_uV - min_uV;

	return 100 - (((req_uV * 100) - (min_uV * 100)) / diff);
}

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;
	unsigned int period = pwm_get_period(drvdata->pwm);
	int duty_cycle;
	int ret;

	duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV);

	ret = pwm_config(drvdata->pwm, (period / 100) * duty_cycle, period);
	if (ret) {
		dev_err(&rdev->dev, "Failed to configure PWM\n");
		return ret;
	}

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

static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
	.get_voltage = pwm_regulator_get_voltage,
	.set_voltage = pwm_regulator_set_voltage,
};

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\n");
		return ret;
	}

	drvdata->duty_cycle_table	= duty_cycle_table;
	pwm_regulator_desc.ops		= &pwm_regulator_voltage_table_ops;
	pwm_regulator_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)
{
	pwm_regulator_desc.ops = &pwm_regulator_voltage_continuous_ops;
	pwm_regulator_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;

	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,
					       &pwm_regulator_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)) {
		dev_err(&pdev->dev, "Failed to get PWM\n");
		return PTR_ERR(drvdata->pwm);
	}

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

	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");
Commit	Line	Data
	1	/*
	2	* Regulator driver for PWM Regulators
	3	*
	4	* Copyright (C) 2014 - STMicroelectronics Inc.
	5	*
	6	* Author: Lee Jones <lee.jones@linaro.org>
	7	*
	8	* This program is free software; you can redistribute it and/or modify
	9	* it under the terms of the GNU General Public License version 2 as
	10	* published by the Free Software Foundation.
	11	*/
	12
	13	#include <linux/delay.h>
	14	#include <linux/module.h>
	15	#include <linux/init.h>
	16	#include <linux/err.h>
	17	#include <linux/regulator/driver.h>
	18	#include <linux/regulator/machine.h>
	19	#include <linux/regulator/of_regulator.h>
	20	#include <linux/of.h>
	21	#include <linux/of_device.h>
	22	#include <linux/pwm.h>
	23
	24	struct pwm_regulator_data {
	25	/* Shared */
	26	struct pwm_device *pwm;
	27
	28	/* Voltage table */
	29	struct pwm_voltages *duty_cycle_table;
	30	int state;
	31
	32	/* Continuous voltage */
	33	int volt_uV;
	34	};
	35
	36	struct pwm_voltages {
	37	unsigned int uV;
	38	unsigned int dutycycle;
	39	};
	40
	41	/**
	42	* Voltage table call-backs
	43	*/
	44	static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
	45	{
	46	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	47
	48	return drvdata->state;
	49	}
	50
	51	static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
	52	unsigned selector)
	53	{
	54	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	55	unsigned int pwm_reg_period;
	56	int dutycycle;
	57	int ret;
	58
	59	pwm_reg_period = pwm_get_period(drvdata->pwm);
	60
	61	dutycycle = (pwm_reg_period *
	62	drvdata->duty_cycle_table[selector].dutycycle) / 100;
	63
	64	ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
	65	if (ret) {
	66	dev_err(&rdev->dev, "Failed to configure PWM\n");
	67	return ret;
	68	}
	69
	70	drvdata->state = selector;
	71
	72	ret = pwm_enable(drvdata->pwm);
	73	if (ret) {
	74	dev_err(&rdev->dev, "Failed to enable PWM\n");
	75	return ret;
	76	}
	77
	78	return 0;
	79	}
	80
	81	static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
	82	unsigned selector)
	83	{
	84	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	85
	86	if (selector >= rdev->desc->n_voltages)
	87	return -EINVAL;
	88
	89	return drvdata->duty_cycle_table[selector].uV;
	90	}
	91
	92	/**
	93	* Continuous voltage call-backs
	94	*/
	95	static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV)
	96	{
	97	int min_uV = rdev->constraints->min_uV;
	98	int max_uV = rdev->constraints->max_uV;
	99	int diff = max_uV - min_uV;
	100
	101	return 100 - (((req_uV * 100) - (min_uV * 100)) / diff);
	102	}
	103
	104	static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
	105	{
	106	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	107
	108	return drvdata->volt_uV;
	109	}
	110
	111	static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
	112	int min_uV, int max_uV,
	113	unsigned *selector)
	114	{
	115	struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
	116	unsigned int ramp_delay = rdev->constraints->ramp_delay;
	117	unsigned int period = pwm_get_period(drvdata->pwm);
	118	int duty_cycle;
	119	int ret;
	120
	121	duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV);
	122
	123	ret = pwm_config(drvdata->pwm, (period / 100) * duty_cycle, period);
	124	if (ret) {
	125	dev_err(&rdev->dev, "Failed to configure PWM\n");
	126	return ret;
	127	}
	128
	129	ret = pwm_enable(drvdata->pwm);
	130	if (ret) {
	131	dev_err(&rdev->dev, "Failed to enable PWM\n");
	132	return ret;
	133	}
	134	drvdata->volt_uV = min_uV;
	135
	136	/* Delay required by PWM regulator to settle to the new voltage */
	137	usleep_range(ramp_delay, ramp_delay + 1000);
	138
	139	return 0;
	140	}
	141
	142	static struct regulator_ops pwm_regulator_voltage_table_ops = {
	143	.set_voltage_sel = pwm_regulator_set_voltage_sel,
	144	.get_voltage_sel = pwm_regulator_get_voltage_sel,
	145	.list_voltage = pwm_regulator_list_voltage,
	146	.map_voltage = regulator_map_voltage_iterate,
	147	};
	148
	149	static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
	150	.get_voltage = pwm_regulator_get_voltage,
	151	.set_voltage = pwm_regulator_set_voltage,
	152	};
	153
	154	static struct regulator_desc pwm_regulator_desc = {
	155	.name = "pwm-regulator",
	156	.type = REGULATOR_VOLTAGE,
	157	.owner = THIS_MODULE,
	158	.supply_name = "pwm",
	159	};
	160
	161	static int pwm_regulator_init_table(struct platform_device *pdev,
	162	struct pwm_regulator_data *drvdata)
	163	{
	164	struct device_node *np = pdev->dev.of_node;
	165	struct pwm_voltages *duty_cycle_table;
	166	unsigned int length = 0;
	167	int ret;
	168
	169	of_find_property(np, "voltage-table", &length);
	170
	171	if ((length < sizeof(*duty_cycle_table)) \|\|
	172	(length % sizeof(*duty_cycle_table))) {
	173	dev_err(&pdev->dev,
	174	"voltage-table length(%d) is invalid\n",
	175	length);
	176	return -EINVAL;
	177	}
	178
	179	duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
	180	if (!duty_cycle_table)
	181	return -ENOMEM;
	182
	183	ret = of_property_read_u32_array(np, "voltage-table",
	184	(u32 *)duty_cycle_table,
	185	length / sizeof(u32));
	186	if (ret) {
	187	dev_err(&pdev->dev, "Failed to read voltage-table\n");
	188	return ret;
	189	}
	190
	191	drvdata->duty_cycle_table = duty_cycle_table;
	192	pwm_regulator_desc.ops = &pwm_regulator_voltage_table_ops;
	193	pwm_regulator_desc.n_voltages = length / sizeof(*duty_cycle_table);
	194
	195	return 0;
	196	}
	197
	198	static int pwm_regulator_init_continuous(struct platform_device *pdev,
	199	struct pwm_regulator_data *drvdata)
	200	{
	201	pwm_regulator_desc.ops = &pwm_regulator_voltage_continuous_ops;
	202	pwm_regulator_desc.continuous_voltage_range = true;
	203
	204	return 0;
	205	}
	206
	207	static int pwm_regulator_probe(struct platform_device *pdev)
	208	{
	209	const struct regulator_init_data *init_data;
	210	struct pwm_regulator_data *drvdata;
	211	struct regulator_dev *regulator;
	212	struct regulator_config config = { };
	213	struct device_node *np = pdev->dev.of_node;
	214	int ret;
	215
	216	if (!np) {
	217	dev_err(&pdev->dev, "Device Tree node missing\n");
	218	return -EINVAL;
	219	}
	220
	221	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
	222	if (!drvdata)
	223	return -ENOMEM;
	224
	225	if (of_find_property(np, "voltage-table", NULL))
	226	ret = pwm_regulator_init_table(pdev, drvdata);
	227	else
	228	ret = pwm_regulator_init_continuous(pdev, drvdata);
	229	if (ret)
	230	return ret;
	231
	232	init_data = of_get_regulator_init_data(&pdev->dev, np,
	233	&pwm_regulator_desc);
	234	if (!init_data)
	235	return -ENOMEM;
	236
	237	config.of_node = np;
	238	config.dev = &pdev->dev;
	239	config.driver_data = drvdata;
	240	config.init_data = init_data;
	241
	242	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
	243	if (IS_ERR(drvdata->pwm)) {
	244	dev_err(&pdev->dev, "Failed to get PWM\n");
	245	return PTR_ERR(drvdata->pwm);
	246	}
	247
	248	regulator = devm_regulator_register(&pdev->dev,
	249	&pwm_regulator_desc, &config);
	250	if (IS_ERR(regulator)) {
	251	dev_err(&pdev->dev, "Failed to register regulator %s\n",
	252	pwm_regulator_desc.name);
	253	return PTR_ERR(regulator);
	254	}
	255
	256	return 0;
	257	}
	258
	259	static const struct of_device_id pwm_of_match[] = {
	260	{ .compatible = "pwm-regulator" },
	261	{ },
	262	};
	263	MODULE_DEVICE_TABLE(of, pwm_of_match);
	264
	265	static struct platform_driver pwm_regulator_driver = {
	266	.driver = {
	267	.name = "pwm-regulator",
	268	.of_match_table = of_match_ptr(pwm_of_match),
	269	},
	270	.probe = pwm_regulator_probe,
	271	};
	272
	273	module_platform_driver(pwm_regulator_driver);
	274
	275	MODULE_LICENSE("GPL");
	276	MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
	277	MODULE_DESCRIPTION("PWM Regulator Driver");
	278	MODULE_ALIAS("platform:pwm-regulator");