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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
24struct pwm_regulator_data {
25
26 struct pwm_device *pwm;
27
28
29 struct pwm_voltages *duty_cycle_table;
30
31
32 struct regulator_desc desc;
33
34
35 struct regulator_ops ops;
36
37 int state;
38
39
40 int volt_uV;
41};
42
43struct pwm_voltages {
44 unsigned int uV;
45 unsigned int dutycycle;
46};
47
48
49
50
51static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
52{
53 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
54
55 return drvdata->state;
56}
57
58static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
59 unsigned selector)
60{
61 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
62 unsigned int pwm_reg_period;
63 int dutycycle;
64 int ret;
65
66 pwm_reg_period = pwm_get_period(drvdata->pwm);
67
68 dutycycle = (pwm_reg_period *
69 drvdata->duty_cycle_table[selector].dutycycle) / 100;
70
71 ret = pwm_config(drvdata->pwm, dutycycle, pwm_reg_period);
72 if (ret) {
73 dev_err(&rdev->dev, "Failed to configure PWM\n");
74 return ret;
75 }
76
77 drvdata->state = selector;
78
79 return 0;
80}
81
82static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
83 unsigned selector)
84{
85 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
86
87 if (selector >= rdev->desc->n_voltages)
88 return -EINVAL;
89
90 return drvdata->duty_cycle_table[selector].uV;
91}
92
93static int pwm_regulator_enable(struct regulator_dev *dev)
94{
95 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
96
97 return pwm_enable(drvdata->pwm);
98}
99
100static int pwm_regulator_disable(struct regulator_dev *dev)
101{
102 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
103
104 pwm_disable(drvdata->pwm);
105
106 return 0;
107}
108
109static int pwm_regulator_is_enabled(struct regulator_dev *dev)
110{
111 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
112
113 return pwm_is_enabled(drvdata->pwm);
114}
115
116
117
118
119static int pwm_voltage_to_duty_cycle_percentage(struct regulator_dev *rdev, int req_uV)
120{
121 int min_uV = rdev->constraints->min_uV;
122 int max_uV = rdev->constraints->max_uV;
123 int diff = max_uV - min_uV;
124
125 return ((req_uV * 100) - (min_uV * 100)) / diff;
126}
127
128static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
129{
130 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
131
132 return drvdata->volt_uV;
133}
134
135static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
136 int min_uV, int max_uV,
137 unsigned *selector)
138{
139 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
140 unsigned int ramp_delay = rdev->constraints->ramp_delay;
141 unsigned int period = pwm_get_period(drvdata->pwm);
142 int duty_cycle;
143 int ret;
144
145 duty_cycle = pwm_voltage_to_duty_cycle_percentage(rdev, min_uV);
146
147 ret = pwm_config(drvdata->pwm, (period / 100) * duty_cycle, period);
148 if (ret) {
149 dev_err(&rdev->dev, "Failed to configure PWM\n");
150 return ret;
151 }
152
153 ret = pwm_enable(drvdata->pwm);
154 if (ret) {
155 dev_err(&rdev->dev, "Failed to enable PWM\n");
156 return ret;
157 }
158 drvdata->volt_uV = min_uV;
159
160
161 usleep_range(ramp_delay, ramp_delay + 1000);
162
163 return 0;
164}
165
166static struct regulator_ops pwm_regulator_voltage_table_ops = {
167 .set_voltage_sel = pwm_regulator_set_voltage_sel,
168 .get_voltage_sel = pwm_regulator_get_voltage_sel,
169 .list_voltage = pwm_regulator_list_voltage,
170 .map_voltage = regulator_map_voltage_iterate,
171 .enable = pwm_regulator_enable,
172 .disable = pwm_regulator_disable,
173 .is_enabled = pwm_regulator_is_enabled,
174};
175
176static struct regulator_ops pwm_regulator_voltage_continuous_ops = {
177 .get_voltage = pwm_regulator_get_voltage,
178 .set_voltage = pwm_regulator_set_voltage,
179 .enable = pwm_regulator_enable,
180 .disable = pwm_regulator_disable,
181 .is_enabled = pwm_regulator_is_enabled,
182};
183
184static struct regulator_desc pwm_regulator_desc = {
185 .name = "pwm-regulator",
186 .type = REGULATOR_VOLTAGE,
187 .owner = THIS_MODULE,
188 .supply_name = "pwm",
189};
190
191static int pwm_regulator_init_table(struct platform_device *pdev,
192 struct pwm_regulator_data *drvdata)
193{
194 struct device_node *np = pdev->dev.of_node;
195 struct pwm_voltages *duty_cycle_table;
196 unsigned int length = 0;
197 int ret;
198
199 of_find_property(np, "voltage-table", &length);
200
201 if ((length < sizeof(*duty_cycle_table)) ||
202 (length % sizeof(*duty_cycle_table))) {
203 dev_err(&pdev->dev,
204 "voltage-table length(%d) is invalid\n",
205 length);
206 return -EINVAL;
207 }
208
209 duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
210 if (!duty_cycle_table)
211 return -ENOMEM;
212
213 ret = of_property_read_u32_array(np, "voltage-table",
214 (u32 *)duty_cycle_table,
215 length / sizeof(u32));
216 if (ret) {
217 dev_err(&pdev->dev, "Failed to read voltage-table\n");
218 return ret;
219 }
220
221 drvdata->duty_cycle_table = duty_cycle_table;
222 memcpy(&drvdata->ops, &pwm_regulator_voltage_table_ops,
223 sizeof(drvdata->ops));
224 drvdata->desc.ops = &drvdata->ops;
225 drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);
226
227 return 0;
228}
229
230static int pwm_regulator_init_continuous(struct platform_device *pdev,
231 struct pwm_regulator_data *drvdata)
232{
233 memcpy(&drvdata->ops, &pwm_regulator_voltage_continuous_ops,
234 sizeof(drvdata->ops));
235 drvdata->desc.ops = &drvdata->ops;
236 drvdata->desc.continuous_voltage_range = true;
237
238 return 0;
239}
240
241static int pwm_regulator_probe(struct platform_device *pdev)
242{
243 const struct regulator_init_data *init_data;
244 struct pwm_regulator_data *drvdata;
245 struct regulator_dev *regulator;
246 struct regulator_config config = { };
247 struct device_node *np = pdev->dev.of_node;
248 int ret;
249
250 if (!np) {
251 dev_err(&pdev->dev, "Device Tree node missing\n");
252 return -EINVAL;
253 }
254
255 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
256 if (!drvdata)
257 return -ENOMEM;
258
259 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
260
261 if (of_find_property(np, "voltage-table", NULL))
262 ret = pwm_regulator_init_table(pdev, drvdata);
263 else
264 ret = pwm_regulator_init_continuous(pdev, drvdata);
265 if (ret)
266 return ret;
267
268 init_data = of_get_regulator_init_data(&pdev->dev, np,
269 &drvdata->desc);
270 if (!init_data)
271 return -ENOMEM;
272
273 config.of_node = np;
274 config.dev = &pdev->dev;
275 config.driver_data = drvdata;
276 config.init_data = init_data;
277
278 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
279 if (IS_ERR(drvdata->pwm)) {
280 dev_err(&pdev->dev, "Failed to get PWM\n");
281 return PTR_ERR(drvdata->pwm);
282 }
283
284 regulator = devm_regulator_register(&pdev->dev,
285 &drvdata->desc, &config);
286 if (IS_ERR(regulator)) {
287 dev_err(&pdev->dev, "Failed to register regulator %s\n",
288 drvdata->desc.name);
289 return PTR_ERR(regulator);
290 }
291
292 return 0;
293}
294
295static const struct of_device_id pwm_of_match[] = {
296 { .compatible = "pwm-regulator" },
297 { },
298};
299MODULE_DEVICE_TABLE(of, pwm_of_match);
300
301static struct platform_driver pwm_regulator_driver = {
302 .driver = {
303 .name = "pwm-regulator",
304 .of_match_table = of_match_ptr(pwm_of_match),
305 },
306 .probe = pwm_regulator_probe,
307};
308
309module_platform_driver(pwm_regulator_driver);
310
311MODULE_LICENSE("GPL");
312MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
313MODULE_DESCRIPTION("PWM Regulator Driver");
314MODULE_ALIAS("platform:pwm-regulator");
315
