blob: d3f55eaea0581999e5b5d14dbd04c32fa5f5ecda [file] [log] [blame]
Chris Zhongaa66cc62014-09-28 10:28:53 +08001/*
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/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
23struct pwm_regulator_data {
24 struct regulator_desc desc;
25 struct pwm_voltages *duty_cycle_table;
26 struct pwm_device *pwm;
27 bool enabled;
28 int state;
29};
30
31struct pwm_voltages {
32 unsigned int uV;
33 unsigned int dutycycle;
34};
35
36static int pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
37{
38 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
39
40 return drvdata->state;
41}
42
43static int pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
44 unsigned selector)
45{
46 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
47 unsigned int pwm_reg_period;
48 int dutycycle;
49 int ret;
50
51 pwm_reg_period = pwm_get_period(drvdata->pwm);
52
53 dutycycle = (pwm_reg_period *
54 drvdata->duty_cycle_table[selector].dutycycle) / 100;
55
56 ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
57 if (ret) {
58 dev_err(&dev->dev, "Failed to configure PWM\n");
59 return ret;
60 }
61
62 drvdata->state = selector;
63
64 if (!drvdata->enabled) {
65 ret = pwm_enable(drvdata->pwm);
66 if (ret) {
67 dev_err(&dev->dev, "Failed to enable PWM\n");
68 return ret;
69 }
70 drvdata->enabled = true;
71 }
72
73 return 0;
74}
75
76static int pwm_regulator_list_voltage(struct regulator_dev *dev,
77 unsigned selector)
78{
79 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
80
81 if (selector >= drvdata->desc.n_voltages)
82 return -EINVAL;
83
84 return drvdata->duty_cycle_table[selector].uV;
85}
86
87static struct regulator_ops pwm_regulator_voltage_ops = {
88 .set_voltage_sel = pwm_regulator_set_voltage_sel,
89 .get_voltage_sel = pwm_regulator_get_voltage_sel,
90 .list_voltage = pwm_regulator_list_voltage,
91 .map_voltage = regulator_map_voltage_iterate,
92};
93
94static const struct regulator_desc pwm_regulator_desc = {
95 .name = "pwm-regulator",
96 .ops = &pwm_regulator_voltage_ops,
97 .type = REGULATOR_VOLTAGE,
98 .owner = THIS_MODULE,
99 .supply_name = "pwm",
100};
101
102static int pwm_regulator_probe(struct platform_device *pdev)
103{
104 struct pwm_regulator_data *drvdata;
105 struct property *prop;
106 struct regulator_dev *regulator;
107 struct regulator_config config = { };
108 struct device_node *np = pdev->dev.of_node;
109 int length, ret;
110
111 if (!np) {
112 dev_err(&pdev->dev, "Device Tree node missing\n");
113 return -EINVAL;
114 }
115
116 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
117 if (!drvdata)
118 return -ENOMEM;
119
120 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(pwm_regulator_desc));
121
122 /* determine the number of voltage-table */
123 prop = of_find_property(np, "voltage-table", &length);
124 if (!prop) {
125 dev_err(&pdev->dev, "No voltage-table\n");
126 return -EINVAL;
127 }
128
129 if ((length < sizeof(*drvdata->duty_cycle_table)) ||
130 (length % sizeof(*drvdata->duty_cycle_table))) {
131 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
132 length);
133 return -EINVAL;
134 }
135
136 drvdata->desc.n_voltages = length / sizeof(*drvdata->duty_cycle_table);
137
138 drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev,
139 length, GFP_KERNEL);
140 if (!drvdata->duty_cycle_table)
141 return -ENOMEM;
142
143 /* read voltage table from DT property */
144 ret = of_property_read_u32_array(np, "voltage-table",
145 (u32 *)drvdata->duty_cycle_table,
146 length / sizeof(u32));
147 if (ret < 0) {
148 dev_err(&pdev->dev, "read voltage-table failed\n");
149 return ret;
150 }
151
152 config.init_data = of_get_regulator_init_data(&pdev->dev, np);
153 if (!config.init_data)
154 return -ENOMEM;
155
156 config.of_node = np;
157 config.dev = &pdev->dev;
158 config.driver_data = drvdata;
159
160 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
161 if (IS_ERR(drvdata->pwm)) {
162 dev_err(&pdev->dev, "Failed to get PWM\n");
163 return PTR_ERR(drvdata->pwm);
164 }
165
166 regulator = devm_regulator_register(&pdev->dev,
167 &drvdata->desc, &config);
168 if (IS_ERR(regulator)) {
169 dev_err(&pdev->dev, "Failed to register regulator %s\n",
170 drvdata->desc.name);
171 return PTR_ERR(regulator);
172 }
173
174 return 0;
175}
176
177static const struct of_device_id pwm_of_match[] = {
178 { .compatible = "pwm-regulator" },
179 { },
180};
181MODULE_DEVICE_TABLE(of, pwm_of_match);
182
183static struct platform_driver pwm_regulator_driver = {
184 .driver = {
185 .name = "pwm-regulator",
186 .owner = THIS_MODULE,
187 .of_match_table = of_match_ptr(pwm_of_match),
188 },
189 .probe = pwm_regulator_probe,
190};
191
192module_platform_driver(pwm_regulator_driver);
193
194MODULE_LICENSE("GPL");
195MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
196MODULE_DESCRIPTION("PWM Regulator Driver");
197MODULE_ALIAS("platform:pwm-regulator");