tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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");