1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
/*
* 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>
struct pwm_regulator_data {
struct regulator_desc desc;
struct pwm_voltages *duty_cycle_table;
struct pwm_device *pwm;
bool enabled;
int state;
};
struct pwm_voltages {
unsigned int uV;
unsigned int dutycycle;
};
static int pwm_regulator_get_voltage_sel(struct regulator_dev *dev)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
return drvdata->state;
}
static int pwm_regulator_set_voltage_sel(struct regulator_dev *dev,
unsigned selector)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
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(&dev->dev, "Failed to configure PWM\n");
return ret;
}
drvdata->state = selector;
if (!drvdata->enabled) {
ret = pwm_enable(drvdata->pwm);
if (ret) {
dev_err(&dev->dev, "Failed to enable PWM\n");
return ret;
}
drvdata->enabled = true;
}
return 0;
}
static int pwm_regulator_list_voltage(struct regulator_dev *dev,
unsigned selector)
{
struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
if (selector >= drvdata->desc.n_voltages)
return -EINVAL;
return drvdata->duty_cycle_table[selector].uV;
}
static struct regulator_ops pwm_regulator_voltage_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 const struct regulator_desc pwm_regulator_desc = {
.name = "pwm-regulator",
.ops = &pwm_regulator_voltage_ops,
.type = REGULATOR_VOLTAGE,
.owner = THIS_MODULE,
.supply_name = "pwm",
};
static int pwm_regulator_probe(struct platform_device *pdev)
{
struct pwm_regulator_data *drvdata;
struct property *prop;
struct regulator_dev *regulator;
struct regulator_config config = { };
struct device_node *np = pdev->dev.of_node;
int length, 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(pwm_regulator_desc));
/* determine the number of voltage-table */
prop = of_find_property(np, "voltage-table", &length);
if (!prop) {
dev_err(&pdev->dev, "No voltage-table\n");
return -EINVAL;
}
if ((length < sizeof(*drvdata->duty_cycle_table)) ||
(length % sizeof(*drvdata->duty_cycle_table))) {
dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
length);
return -EINVAL;
}
drvdata->desc.n_voltages = length / sizeof(*drvdata->duty_cycle_table);
drvdata->duty_cycle_table = devm_kzalloc(&pdev->dev,
length, GFP_KERNEL);
if (!drvdata->duty_cycle_table)
return -ENOMEM;
/* read voltage table from DT property */
ret = of_property_read_u32_array(np, "voltage-table",
(u32 *)drvdata->duty_cycle_table,
length / sizeof(u32));
if (ret < 0) {
dev_err(&pdev->dev, "read voltage-table failed\n");
return ret;
}
config.init_data = of_get_regulator_init_data(&pdev->dev, np);
if (!config.init_data)
return -ENOMEM;
config.of_node = np;
config.dev = &pdev->dev;
config.driver_data = drvdata;
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,
&drvdata->desc, &config);
if (IS_ERR(regulator)) {
dev_err(&pdev->dev, "Failed to register regulator %s\n",
drvdata->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");
|
