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1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Regulator driver for PWM Regulators
4 *
5 * Copyright (C) 2014 - STMicroelectronics Inc.
6 *
7 * Author: Lee Jones <lee.jones@linaro.org>
8 */
9
10#include <linux/module.h>
11#include <linux/init.h>
12#include <linux/err.h>
13#include <linux/regulator/driver.h>
14#include <linux/regulator/machine.h>
15#include <linux/regulator/of_regulator.h>
16#include <linux/of.h>
17#include <linux/of_device.h>
18#include <linux/pwm.h>
19#include <linux/gpio/consumer.h>
20
21struct pwm_continuous_reg_data {
22 unsigned int min_uV_dutycycle;
23 unsigned int max_uV_dutycycle;
24 unsigned int dutycycle_unit;
25};
26
27struct pwm_regulator_data {
28 /* Shared */
29 struct pwm_device *pwm;
30
31 /* Voltage table */
32 struct pwm_voltages *duty_cycle_table;
33
34 /* Continuous mode info */
35 struct pwm_continuous_reg_data continuous;
36
37 /* regulator descriptor */
38 struct regulator_desc desc;
39
40 int state;
41
42 /* Enable GPIO */
43 struct gpio_desc *enb_gpio;
44};
45
46struct pwm_voltages {
47 unsigned int uV;
48 unsigned int dutycycle;
49};
50
51/*
52 * Voltage table call-backs
53 */
54static void pwm_regulator_init_state(struct regulator_dev *rdev)
55{
56 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
57 struct pwm_state pwm_state;
58 unsigned int dutycycle;
59 int i;
60
61 pwm_get_state(drvdata->pwm, &pwm_state);
62 dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
63
64 for (i = 0; i < rdev->desc->n_voltages; i++) {
65 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
66 drvdata->state = i;
67 return;
68 }
69 }
70}
71
72static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
73{
74 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
75
76 if (drvdata->state < 0)
77 pwm_regulator_init_state(rdev);
78
79 return drvdata->state;
80}
81
82static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
83 unsigned selector)
84{
85 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
86 struct pwm_state pstate;
87 int ret;
88
89 pwm_init_state(drvdata->pwm, &pstate);
90 pwm_set_relative_duty_cycle(&pstate,
91 drvdata->duty_cycle_table[selector].dutycycle, 100);
92
93 ret = pwm_apply_state(drvdata->pwm, &pstate);
94 if (ret) {
95 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
96 return ret;
97 }
98
99 drvdata->state = selector;
100
101 return 0;
102}
103
104static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
105 unsigned selector)
106{
107 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
108
109 if (selector >= rdev->desc->n_voltages)
110 return -EINVAL;
111
112 return drvdata->duty_cycle_table[selector].uV;
113}
114
115static int pwm_regulator_enable(struct regulator_dev *dev)
116{
117 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
118
119 gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
120
121 return pwm_enable(drvdata->pwm);
122}
123
124static int pwm_regulator_disable(struct regulator_dev *dev)
125{
126 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
127
128 pwm_disable(drvdata->pwm);
129
130 gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
131
132 return 0;
133}
134
135static int pwm_regulator_is_enabled(struct regulator_dev *dev)
136{
137 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
138
139 if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
140 return false;
141
142 return pwm_is_enabled(drvdata->pwm);
143}
144
145static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
146{
147 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
148 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
149 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
150 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
151 int min_uV = rdev->constraints->min_uV;
152 int max_uV = rdev->constraints->max_uV;
153 int diff_uV = max_uV - min_uV;
154 struct pwm_state pstate;
155 unsigned int diff_duty;
156 unsigned int voltage;
157
158 pwm_get_state(drvdata->pwm, &pstate);
159
160 voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
161
162 /*
163 * The dutycycle for min_uV might be greater than the one for max_uV.
164 * This is happening when the user needs an inversed polarity, but the
165 * PWM device does not support inversing it in hardware.
166 */
167 if (max_uV_duty < min_uV_duty) {
168 voltage = min_uV_duty - voltage;
169 diff_duty = min_uV_duty - max_uV_duty;
170 } else {
171 voltage = voltage - min_uV_duty;
172 diff_duty = max_uV_duty - min_uV_duty;
173 }
174
175 voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
176
177 return voltage + min_uV;
178}
179
180static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
181 int req_min_uV, int req_max_uV,
182 unsigned int *selector)
183{
184 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
185 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
186 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
187 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
188 int min_uV = rdev->constraints->min_uV;
189 int max_uV = rdev->constraints->max_uV;
190 int diff_uV = max_uV - min_uV;
191 struct pwm_state pstate;
192 unsigned int diff_duty;
193 unsigned int dutycycle;
194 int ret;
195
196 pwm_init_state(drvdata->pwm, &pstate);
197
198 /*
199 * The dutycycle for min_uV might be greater than the one for max_uV.
200 * This is happening when the user needs an inversed polarity, but the
201 * PWM device does not support inversing it in hardware.
202 */
203 if (max_uV_duty < min_uV_duty)
204 diff_duty = min_uV_duty - max_uV_duty;
205 else
206 diff_duty = max_uV_duty - min_uV_duty;
207
208 dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
209 diff_duty,
210 diff_uV);
211
212 if (max_uV_duty < min_uV_duty)
213 dutycycle = min_uV_duty - dutycycle;
214 else
215 dutycycle = min_uV_duty + dutycycle;
216
217 pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
218
219 ret = pwm_apply_state(drvdata->pwm, &pstate);
220 if (ret) {
221 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
222 return ret;
223 }
224
225 return 0;
226}
227
228static const struct regulator_ops pwm_regulator_voltage_table_ops = {
229 .set_voltage_sel = pwm_regulator_set_voltage_sel,
230 .get_voltage_sel = pwm_regulator_get_voltage_sel,
231 .list_voltage = pwm_regulator_list_voltage,
232 .map_voltage = regulator_map_voltage_iterate,
233 .enable = pwm_regulator_enable,
234 .disable = pwm_regulator_disable,
235 .is_enabled = pwm_regulator_is_enabled,
236};
237
238static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
239 .get_voltage = pwm_regulator_get_voltage,
240 .set_voltage = pwm_regulator_set_voltage,
241 .enable = pwm_regulator_enable,
242 .disable = pwm_regulator_disable,
243 .is_enabled = pwm_regulator_is_enabled,
244};
245
246static const struct regulator_desc pwm_regulator_desc = {
247 .name = "pwm-regulator",
248 .type = REGULATOR_VOLTAGE,
249 .owner = THIS_MODULE,
250 .supply_name = "pwm",
251};
252
253static int pwm_regulator_init_table(struct platform_device *pdev,
254 struct pwm_regulator_data *drvdata)
255{
256 struct device_node *np = pdev->dev.of_node;
257 struct pwm_voltages *duty_cycle_table;
258 unsigned int length = 0;
259 int ret;
260
261 of_find_property(np, "voltage-table", &length);
262
263 if ((length < sizeof(*duty_cycle_table)) ||
264 (length % sizeof(*duty_cycle_table))) {
265 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
266 length);
267 return -EINVAL;
268 }
269
270 duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
271 if (!duty_cycle_table)
272 return -ENOMEM;
273
274 ret = of_property_read_u32_array(np, "voltage-table",
275 (u32 *)duty_cycle_table,
276 length / sizeof(u32));
277 if (ret) {
278 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
279 return ret;
280 }
281
282 drvdata->state = -ENOTRECOVERABLE;
283 drvdata->duty_cycle_table = duty_cycle_table;
284 drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
285 drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);
286
287 return 0;
288}
289
290static int pwm_regulator_init_continuous(struct platform_device *pdev,
291 struct pwm_regulator_data *drvdata)
292{
293 u32 dutycycle_range[2] = { 0, 100 };
294 u32 dutycycle_unit = 100;
295
296 drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
297 drvdata->desc.continuous_voltage_range = true;
298
299 of_property_read_u32_array(pdev->dev.of_node,
300 "pwm-dutycycle-range",
301 dutycycle_range, 2);
302 of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
303 &dutycycle_unit);
304
305 if (dutycycle_range[0] > dutycycle_unit ||
306 dutycycle_range[1] > dutycycle_unit)
307 return -EINVAL;
308
309 drvdata->continuous.dutycycle_unit = dutycycle_unit;
310 drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
311 drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
312
313 return 0;
314}
315
316static int pwm_regulator_probe(struct platform_device *pdev)
317{
318 const struct regulator_init_data *init_data;
319 struct pwm_regulator_data *drvdata;
320 struct regulator_dev *regulator;
321 struct regulator_config config = { };
322 struct device_node *np = pdev->dev.of_node;
323 enum gpiod_flags gpio_flags;
324 int ret;
325
326 if (!np) {
327 dev_err(&pdev->dev, "Device Tree node missing\n");
328 return -EINVAL;
329 }
330
331 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
332 if (!drvdata)
333 return -ENOMEM;
334
335 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
336
337 if (of_find_property(np, "voltage-table", NULL))
338 ret = pwm_regulator_init_table(pdev, drvdata);
339 else
340 ret = pwm_regulator_init_continuous(pdev, drvdata);
341 if (ret)
342 return ret;
343
344 init_data = of_get_regulator_init_data(&pdev->dev, np,
345 &drvdata->desc);
346 if (!init_data)
347 return -ENOMEM;
348
349 config.of_node = np;
350 config.dev = &pdev->dev;
351 config.driver_data = drvdata;
352 config.init_data = init_data;
353
354 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
355 if (IS_ERR(drvdata->pwm)) {
356 ret = PTR_ERR(drvdata->pwm);
357 if (ret == -EPROBE_DEFER)
358 dev_dbg(&pdev->dev,
359 "Failed to get PWM, deferring probe\n");
360 else
361 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
362 return ret;
363 }
364
365 if (init_data->constraints.boot_on || init_data->constraints.always_on)
366 gpio_flags = GPIOD_OUT_HIGH;
367 else
368 gpio_flags = GPIOD_OUT_LOW;
369 drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
370 gpio_flags);
371 if (IS_ERR(drvdata->enb_gpio)) {
372 ret = PTR_ERR(drvdata->enb_gpio);
373 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
374 return ret;
375 }
376
377 ret = pwm_adjust_config(drvdata->pwm);
378 if (ret)
379 return ret;
380
381 regulator = devm_regulator_register(&pdev->dev,
382 &drvdata->desc, &config);
383 if (IS_ERR(regulator)) {
384 ret = PTR_ERR(regulator);
385 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
386 drvdata->desc.name, ret);
387 return ret;
388 }
389
390 return 0;
391}
392
393static const struct of_device_id pwm_of_match[] = {
394 { .compatible = "pwm-regulator" },
395 { },
396};
397MODULE_DEVICE_TABLE(of, pwm_of_match);
398
399static struct platform_driver pwm_regulator_driver = {
400 .driver = {
401 .name = "pwm-regulator",
402 .of_match_table = of_match_ptr(pwm_of_match),
403 },
404 .probe = pwm_regulator_probe,
405};
406
407module_platform_driver(pwm_regulator_driver);
408
409MODULE_LICENSE("GPL");
410MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
411MODULE_DESCRIPTION("PWM Regulator Driver");
412MODULE_ALIAS("platform:pwm-regulator");