1/*
  2 * Regulator driver for ST's 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/module.h>
 14#include <linux/init.h>
 15#include <linux/err.h>
 16#include <linux/regulator/driver.h>
 17#include <linux/regulator/machine.h>
 18#include <linux/regulator/of_regulator.h>
 19#include <linux/of.h>
 20#include <linux/of_device.h>
 21#include <linux/pwm.h>
 22
 23#define ST_PWM_REG_PERIOD 8448
 24
 25struct st_pwm_regulator_pdata {
 26	const struct regulator_desc *desc;
 27	struct st_pwm_voltages *duty_cycle_table;
 28};
 29
 30struct st_pwm_regulator_data {
 31	const struct st_pwm_regulator_pdata *pdata;
 32	struct pwm_device *pwm;
 33	bool enabled;
 34	int state;
 35};
 36
 37struct st_pwm_voltages {
 38	unsigned int uV;
 39	unsigned int dutycycle;
 40};
 41
 42static int st_pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
 43{
 44	struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 45
 46	return drvdata->state;
 47}
 48
 49static int st_pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
 50					    unsigned selector)
 51{
 52	struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 53	int dutycycle;
 54	int ret;
 55
 56	dutycycle = (ST_PWM_REG_PERIOD / 100) *
 57		drvdata->pdata->duty_cycle_table[selector].dutycycle;
 58
 59	ret = pwm_config(drvdata->pwm, dutycycle, ST_PWM_REG_PERIOD);
 60	if (ret) {
 61		dev_err(&dev->dev, "Failed to configure PWM\n");
 62		return ret;
 63	}
 64
 65	drvdata->state = selector;
 66
 67	if (!drvdata->enabled) {
 68		ret = pwm_enable(drvdata->pwm);
 69		if (ret) {
 70			dev_err(&dev->dev, "Failed to enable PWM\n");
 71			return ret;
 72		}
 73		drvdata->enabled = true;
 74	}
 75
 76	return 0;
 77}
 78
 79static int st_pwm_regulator_list_voltage(struct regulator_dev *dev,
 80					 unsigned selector)
 81{
 82	struct st_pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
 83
 84	if (selector >= dev->desc->n_voltages)
 85		return -EINVAL;
 86
 87	return drvdata->pdata->duty_cycle_table[selector].uV;
 88}
 89
 90static struct regulator_ops st_pwm_regulator_voltage_ops = {
 91	.set_voltage_sel = st_pwm_regulator_set_voltage_sel,
 92	.get_voltage_sel = st_pwm_regulator_get_voltage_sel,
 93	.list_voltage    = st_pwm_regulator_list_voltage,
 94	.map_voltage     = regulator_map_voltage_iterate,
 95};
 96
 97static struct st_pwm_voltages b2105_duty_cycle_table[] = {
 98	{ .uV = 1114000, .dutycycle = 0,  },
 99	{ .uV = 1095000, .dutycycle = 10, },
100	{ .uV = 1076000, .dutycycle = 20, },
101	{ .uV = 1056000, .dutycycle = 30, },
102	{ .uV = 1036000, .dutycycle = 40, },
103	{ .uV = 1016000, .dutycycle = 50, },
104	/* WARNING: Values above 50% duty-cycle cause boot failures. */
105};
106
107static const struct regulator_desc b2105_desc = {
108	.name		= "b2105-pwm-regulator",
109	.ops		= &st_pwm_regulator_voltage_ops,
110	.type		= REGULATOR_VOLTAGE,
111	.owner		= THIS_MODULE,
112	.n_voltages	= ARRAY_SIZE(b2105_duty_cycle_table),
113	.supply_name    = "pwm",
114};
115
116static const struct st_pwm_regulator_pdata b2105_info = {
117	.desc		  = &b2105_desc,
118	.duty_cycle_table = b2105_duty_cycle_table,
119};
120
121static struct of_device_id st_pwm_of_match[] = {
122	{ .compatible = "st,b2105-pwm-regulator", .data = &b2105_info, },
123	{ },
124};
125MODULE_DEVICE_TABLE(of, st_pwm_of_match);
126
127static int st_pwm_regulator_probe(struct platform_device *pdev)
128{
129	struct st_pwm_regulator_data *drvdata;
130	struct regulator_dev *regulator;
131	struct regulator_config config = { };
132	struct device_node *np = pdev->dev.of_node;
133	const struct of_device_id *of_match;
134
135	if (!np) {
136		dev_err(&pdev->dev, "Device Tree node missing\n");
137		return -EINVAL;
138	}
139
140	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
141	if (!drvdata)
142		return -ENOMEM;
143
144	of_match = of_match_device(st_pwm_of_match, &pdev->dev);
145	if (!of_match) {
146		dev_err(&pdev->dev, "failed to match of device\n");
147		return -ENODEV;
148	}
149	drvdata->pdata = of_match->data;
150
151	config.init_data = of_get_regulator_init_data(&pdev->dev, np);
152	if (!config.init_data)
153		return -ENOMEM;
154
155	config.of_node = np;
156	config.dev = &pdev->dev;
157	config.driver_data = drvdata;
158
159	drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
160	if (IS_ERR(drvdata->pwm)) {
161		dev_err(&pdev->dev, "Failed to get PWM\n");
162		return PTR_ERR(drvdata->pwm);
163	}
164
165	regulator = devm_regulator_register(&pdev->dev,
166					    drvdata->pdata->desc, &config);
167	if (IS_ERR(regulator)) {
168		dev_err(&pdev->dev, "Failed to register regulator %s\n",
169			drvdata->pdata->desc->name);
170		return PTR_ERR(regulator);
171	}
172
173	return 0;
174}
175
176static struct platform_driver st_pwm_regulator_driver = {
177	.driver = {
178		.name		= "st-pwm-regulator",
179		.owner		= THIS_MODULE,
180		.of_match_table = of_match_ptr(st_pwm_of_match),
181	},
182	.probe = st_pwm_regulator_probe,
183};
184
185module_platform_driver(st_pwm_regulator_driver);
186
187MODULE_LICENSE("GPL");
188MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
189MODULE_DESCRIPTION("ST PWM Regulator Driver");
190MODULE_ALIAS("platform:st_pwm-regulator");