1/*
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#include <linux/gpio/consumer.h>
23
24struct pwm_continuous_reg_data {
25 unsigned int min_uV_dutycycle;
26 unsigned int max_uV_dutycycle;
27 unsigned int dutycycle_unit;
28};
29
30struct pwm_regulator_data {
31 /* Shared */
32 struct pwm_device *pwm;
33
34 /* Voltage table */
35 struct pwm_voltages *duty_cycle_table;
36
37 /* Continuous mode info */
38 struct pwm_continuous_reg_data continuous;
39
40 /* regulator descriptor */
41 struct regulator_desc desc;
42
43 int state;
44
45 /* Enable GPIO */
46 struct gpio_desc *enb_gpio;
47};
48
49struct pwm_voltages {
50 unsigned int uV;
51 unsigned int dutycycle;
52};
53
54/**
55 * Voltage table call-backs
56 */
57static void pwm_regulator_init_state(struct regulator_dev *rdev)
58{
59 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
60 struct pwm_state pwm_state;
61 unsigned int dutycycle;
62 int i;
63
64 pwm_get_state(drvdata->pwm, &pwm_state);
65 dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
66
67 for (i = 0; i < rdev->desc->n_voltages; i++) {
68 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
69 drvdata->state = i;
70 return;
71 }
72 }
73}
74
75static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
76{
77 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
78
79 if (drvdata->state < 0)
80 pwm_regulator_init_state(rdev);
81
82 return drvdata->state;
83}
84
85static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
86 unsigned selector)
87{
88 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
89 struct pwm_state pstate;
90 int ret;
91
92 pwm_init_state(drvdata->pwm, &pstate);
93 pwm_set_relative_duty_cycle(&pstate,
94 drvdata->duty_cycle_table[selector].dutycycle, 100);
95
96 ret = pwm_apply_state(drvdata->pwm, &pstate);
97 if (ret) {
98 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
99 return ret;
100 }
101
102 drvdata->state = selector;
103
104 return 0;
105}
106
107static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
108 unsigned selector)
109{
110 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
111
112 if (selector >= rdev->desc->n_voltages)
113 return -EINVAL;
114
115 return drvdata->duty_cycle_table[selector].uV;
116}
117
118static int pwm_regulator_enable(struct regulator_dev *dev)
119{
120 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
121
122 gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
123
124 return pwm_enable(drvdata->pwm);
125}
126
127static int pwm_regulator_disable(struct regulator_dev *dev)
128{
129 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
130
131 pwm_disable(drvdata->pwm);
132
133 gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
134
135 return 0;
136}
137
138static int pwm_regulator_is_enabled(struct regulator_dev *dev)
139{
140 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
141
142 if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
143 return false;
144
145 return pwm_is_enabled(drvdata->pwm);
146}
147
148static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
149{
150 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
151 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
152 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
153 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
154 int min_uV = rdev->constraints->min_uV;
155 int max_uV = rdev->constraints->max_uV;
156 int diff_uV = max_uV - min_uV;
157 struct pwm_state pstate;
158 unsigned int diff_duty;
159 unsigned int voltage;
160
161 pwm_get_state(drvdata->pwm, &pstate);
162
163 voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
164
165 /*
166 * The dutycycle for min_uV might be greater than the one for max_uV.
167 * This is happening when the user needs an inversed polarity, but the
168 * PWM device does not support inversing it in hardware.
169 */
170 if (max_uV_duty < min_uV_duty) {
171 voltage = min_uV_duty - voltage;
172 diff_duty = min_uV_duty - max_uV_duty;
173 } else {
174 voltage = voltage - min_uV_duty;
175 diff_duty = max_uV_duty - min_uV_duty;
176 }
177
178 voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
179
180 return voltage + min_uV;
181}
182
183static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
184 int req_min_uV, int req_max_uV,
185 unsigned int *selector)
186{
187 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
188 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
189 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
190 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
191 int min_uV = rdev->constraints->min_uV;
192 int max_uV = rdev->constraints->max_uV;
193 int diff_uV = max_uV - min_uV;
194 struct pwm_state pstate;
195 unsigned int diff_duty;
196 unsigned int dutycycle;
197 int ret;
198
199 pwm_init_state(drvdata->pwm, &pstate);
200
201 /*
202 * The dutycycle for min_uV might be greater than the one for max_uV.
203 * This is happening when the user needs an inversed polarity, but the
204 * PWM device does not support inversing it in hardware.
205 */
206 if (max_uV_duty < min_uV_duty)
207 diff_duty = min_uV_duty - max_uV_duty;
208 else
209 diff_duty = max_uV_duty - min_uV_duty;
210
211 dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
212 diff_duty,
213 diff_uV);
214
215 if (max_uV_duty < min_uV_duty)
216 dutycycle = min_uV_duty - dutycycle;
217 else
218 dutycycle = min_uV_duty + dutycycle;
219
220 pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
221
222 ret = pwm_apply_state(drvdata->pwm, &pstate);
223 if (ret) {
224 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
225 return ret;
226 }
227
228 return 0;
229}
230
231static const struct regulator_ops pwm_regulator_voltage_table_ops = {
232 .set_voltage_sel = pwm_regulator_set_voltage_sel,
233 .get_voltage_sel = pwm_regulator_get_voltage_sel,
234 .list_voltage = pwm_regulator_list_voltage,
235 .map_voltage = regulator_map_voltage_iterate,
236 .enable = pwm_regulator_enable,
237 .disable = pwm_regulator_disable,
238 .is_enabled = pwm_regulator_is_enabled,
239};
240
241static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
242 .get_voltage = pwm_regulator_get_voltage,
243 .set_voltage = pwm_regulator_set_voltage,
244 .enable = pwm_regulator_enable,
245 .disable = pwm_regulator_disable,
246 .is_enabled = pwm_regulator_is_enabled,
247};
248
249static const struct regulator_desc pwm_regulator_desc = {
250 .name = "pwm-regulator",
251 .type = REGULATOR_VOLTAGE,
252 .owner = THIS_MODULE,
253 .supply_name = "pwm",
254};
255
256static int pwm_regulator_init_table(struct platform_device *pdev,
257 struct pwm_regulator_data *drvdata)
258{
259 struct device_node *np = pdev->dev.of_node;
260 struct pwm_voltages *duty_cycle_table;
261 unsigned int length = 0;
262 int ret;
263
264 of_find_property(np, "voltage-table", &length);
265
266 if ((length < sizeof(*duty_cycle_table)) ||
267 (length % sizeof(*duty_cycle_table))) {
268 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
269 length);
270 return -EINVAL;
271 }
272
273 duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
274 if (!duty_cycle_table)
275 return -ENOMEM;
276
277 ret = of_property_read_u32_array(np, "voltage-table",
278 (u32 *)duty_cycle_table,
279 length / sizeof(u32));
280 if (ret) {
281 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
282 return ret;
283 }
284
285 drvdata->state = -EINVAL;
286 drvdata->duty_cycle_table = duty_cycle_table;
287 drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
288 drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);
289
290 return 0;
291}
292
293static int pwm_regulator_init_continuous(struct platform_device *pdev,
294 struct pwm_regulator_data *drvdata)
295{
296 u32 dutycycle_range[2] = { 0, 100 };
297 u32 dutycycle_unit = 100;
298
299 drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
300 drvdata->desc.continuous_voltage_range = true;
301
302 of_property_read_u32_array(pdev->dev.of_node,
303 "pwm-dutycycle-range",
304 dutycycle_range, 2);
305 of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
306 &dutycycle_unit);
307
308 if (dutycycle_range[0] > dutycycle_unit ||
309 dutycycle_range[1] > dutycycle_unit)
310 return -EINVAL;
311
312 drvdata->continuous.dutycycle_unit = dutycycle_unit;
313 drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
314 drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
315
316 return 0;
317}
318
319static int pwm_regulator_probe(struct platform_device *pdev)
320{
321 const struct regulator_init_data *init_data;
322 struct pwm_regulator_data *drvdata;
323 struct regulator_dev *regulator;
324 struct regulator_config config = { };
325 struct device_node *np = pdev->dev.of_node;
326 enum gpiod_flags gpio_flags;
327 int ret;
328
329 if (!np) {
330 dev_err(&pdev->dev, "Device Tree node missing\n");
331 return -EINVAL;
332 }
333
334 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
335 if (!drvdata)
336 return -ENOMEM;
337
338 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
339
340 if (of_find_property(np, "voltage-table", NULL))
341 ret = pwm_regulator_init_table(pdev, drvdata);
342 else
343 ret = pwm_regulator_init_continuous(pdev, drvdata);
344 if (ret)
345 return ret;
346
347 init_data = of_get_regulator_init_data(&pdev->dev, np,
348 &drvdata->desc);
349 if (!init_data)
350 return -ENOMEM;
351
352 config.of_node = np;
353 config.dev = &pdev->dev;
354 config.driver_data = drvdata;
355 config.init_data = init_data;
356
357 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
358 if (IS_ERR(drvdata->pwm)) {
359 ret = PTR_ERR(drvdata->pwm);
360 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
361 return ret;
362 }
363
364 if (init_data->constraints.boot_on || init_data->constraints.always_on)
365 gpio_flags = GPIOD_OUT_HIGH;
366 else
367 gpio_flags = GPIOD_OUT_LOW;
368 drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
369 gpio_flags);
370 if (IS_ERR(drvdata->enb_gpio)) {
371 ret = PTR_ERR(drvdata->enb_gpio);
372 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
373 return ret;
374 }
375
376 ret = pwm_adjust_config(drvdata->pwm);
377 if (ret)
378 return ret;
379
380 regulator = devm_regulator_register(&pdev->dev,
381 &drvdata->desc, &config);
382 if (IS_ERR(regulator)) {
383 ret = PTR_ERR(regulator);
384 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
385 drvdata->desc.name, ret);
386 return ret;
387 }
388
389 return 0;
390}
391
392static const struct of_device_id pwm_of_match[] = {
393 { .compatible = "pwm-regulator" },
394 { },
395};
396MODULE_DEVICE_TABLE(of, pwm_of_match);
397
398static struct platform_driver pwm_regulator_driver = {
399 .driver = {
400 .name = "pwm-regulator",
401 .of_match_table = of_match_ptr(pwm_of_match),
402 },
403 .probe = pwm_regulator_probe,
404};
405
406module_platform_driver(pwm_regulator_driver);
407
408MODULE_LICENSE("GPL");
409MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
410MODULE_DESCRIPTION("PWM Regulator Driver");
411MODULE_ALIAS("platform:pwm-regulator");
412