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/platform_device.h>
14 #include <linux/regulator/driver.h>
15 #include <linux/regulator/machine.h>
16 #include <linux/regulator/of_regulator.h>
17 #include <linux/of.h>
18 #include <linux/pwm.h>
19 #include <linux/gpio/consumer.h>
20
21 struct pwm_continuous_reg_data {
22 unsigned int min_uV_dutycycle;
23 unsigned int max_uV_dutycycle;
24 unsigned int dutycycle_unit;
25 };
26
27 struct 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
46 struct pwm_voltages {
47 unsigned int uV;
48 unsigned int dutycycle;
49 };
50
51 /*
52 * Voltage table call-backs
53 */
pwm_regulator_init_state(struct regulator_dev * rdev)54 static 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
pwm_regulator_get_voltage_sel(struct regulator_dev * rdev)72 static 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
pwm_regulator_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)82 static 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_might_sleep(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
pwm_regulator_list_voltage(struct regulator_dev * rdev,unsigned selector)104 static 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
pwm_regulator_enable(struct regulator_dev * dev)115 static 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
pwm_regulator_disable(struct regulator_dev * dev)124 static 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
pwm_regulator_is_enabled(struct regulator_dev * dev)135 static 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
pwm_regulator_get_voltage(struct regulator_dev * rdev)145 static 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 if (!pstate.enabled) {
161 if (pstate.polarity == PWM_POLARITY_INVERSED)
162 pstate.duty_cycle = pstate.period;
163 else
164 pstate.duty_cycle = 0;
165 }
166
167 voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
168 if (voltage < min(max_uV_duty, min_uV_duty) ||
169 voltage > max(max_uV_duty, min_uV_duty))
170 return -ENOTRECOVERABLE;
171
172 /*
173 * The dutycycle for min_uV might be greater than the one for max_uV.
174 * This is happening when the user needs an inversed polarity, but the
175 * PWM device does not support inversing it in hardware.
176 */
177 if (max_uV_duty < min_uV_duty) {
178 voltage = min_uV_duty - voltage;
179 diff_duty = min_uV_duty - max_uV_duty;
180 } else {
181 voltage = voltage - min_uV_duty;
182 diff_duty = max_uV_duty - min_uV_duty;
183 }
184
185 voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
186
187 return voltage + min_uV;
188 }
189
pwm_regulator_set_voltage(struct regulator_dev * rdev,int req_min_uV,int req_max_uV,unsigned int * selector)190 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
191 int req_min_uV, int req_max_uV,
192 unsigned int *selector)
193 {
194 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
195 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
196 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
197 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
198 int min_uV = rdev->constraints->min_uV;
199 int max_uV = rdev->constraints->max_uV;
200 int diff_uV = max_uV - min_uV;
201 struct pwm_state pstate;
202 unsigned int diff_duty;
203 unsigned int dutycycle;
204 int ret;
205
206 pwm_init_state(drvdata->pwm, &pstate);
207
208 /*
209 * The dutycycle for min_uV might be greater than the one for max_uV.
210 * This is happening when the user needs an inversed polarity, but the
211 * PWM device does not support inversing it in hardware.
212 */
213 if (max_uV_duty < min_uV_duty)
214 diff_duty = min_uV_duty - max_uV_duty;
215 else
216 diff_duty = max_uV_duty - min_uV_duty;
217
218 dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
219 diff_duty,
220 diff_uV);
221
222 if (max_uV_duty < min_uV_duty)
223 dutycycle = min_uV_duty - dutycycle;
224 else
225 dutycycle = min_uV_duty + dutycycle;
226
227 pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
228
229 ret = pwm_apply_might_sleep(drvdata->pwm, &pstate);
230 if (ret) {
231 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
232 return ret;
233 }
234
235 return 0;
236 }
237
238 static const struct regulator_ops pwm_regulator_voltage_table_ops = {
239 .set_voltage_sel = pwm_regulator_set_voltage_sel,
240 .get_voltage_sel = pwm_regulator_get_voltage_sel,
241 .list_voltage = pwm_regulator_list_voltage,
242 .map_voltage = regulator_map_voltage_iterate,
243 .enable = pwm_regulator_enable,
244 .disable = pwm_regulator_disable,
245 .is_enabled = pwm_regulator_is_enabled,
246 };
247
248 static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
249 .get_voltage = pwm_regulator_get_voltage,
250 .set_voltage = pwm_regulator_set_voltage,
251 .enable = pwm_regulator_enable,
252 .disable = pwm_regulator_disable,
253 .is_enabled = pwm_regulator_is_enabled,
254 };
255
256 static const struct regulator_desc pwm_regulator_desc = {
257 .name = "pwm-regulator",
258 .type = REGULATOR_VOLTAGE,
259 .owner = THIS_MODULE,
260 .supply_name = "pwm",
261 };
262
pwm_regulator_init_table(struct platform_device * pdev,struct pwm_regulator_data * drvdata)263 static int pwm_regulator_init_table(struct platform_device *pdev,
264 struct pwm_regulator_data *drvdata)
265 {
266 struct device_node *np = pdev->dev.of_node;
267 struct pwm_voltages *duty_cycle_table;
268 unsigned int length = 0;
269 int ret;
270
271 of_find_property(np, "voltage-table", &length);
272
273 if ((length < sizeof(*duty_cycle_table)) ||
274 (length % sizeof(*duty_cycle_table)))
275 return dev_err_probe(&pdev->dev, -EINVAL,
276 "voltage-table length(%d) is invalid\n",
277 length);
278
279 duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
280 if (!duty_cycle_table)
281 return -ENOMEM;
282
283 ret = of_property_read_u32_array(np, "voltage-table",
284 (u32 *)duty_cycle_table,
285 length / sizeof(u32));
286 if (ret)
287 return dev_err_probe(&pdev->dev, ret,
288 "Failed to read voltage-table\n");
289
290 drvdata->state = -ENOTRECOVERABLE;
291 drvdata->duty_cycle_table = duty_cycle_table;
292 drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
293 drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);
294
295 return 0;
296 }
297
pwm_regulator_init_continuous(struct platform_device * pdev,struct pwm_regulator_data * drvdata)298 static int pwm_regulator_init_continuous(struct platform_device *pdev,
299 struct pwm_regulator_data *drvdata)
300 {
301 u32 dutycycle_range[2] = { 0, 100 };
302 u32 dutycycle_unit = 100;
303
304 drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
305 drvdata->desc.continuous_voltage_range = true;
306
307 of_property_read_u32_array(pdev->dev.of_node,
308 "pwm-dutycycle-range",
309 dutycycle_range, 2);
310 of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
311 &dutycycle_unit);
312
313 if (dutycycle_range[0] > dutycycle_unit ||
314 dutycycle_range[1] > dutycycle_unit)
315 return -EINVAL;
316
317 drvdata->continuous.dutycycle_unit = dutycycle_unit;
318 drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
319 drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
320
321 return 0;
322 }
323
pwm_regulator_init_boot_on(struct platform_device * pdev,struct pwm_regulator_data * drvdata,const struct regulator_init_data * init_data)324 static int pwm_regulator_init_boot_on(struct platform_device *pdev,
325 struct pwm_regulator_data *drvdata,
326 const struct regulator_init_data *init_data)
327 {
328 struct pwm_state pstate;
329
330 if (!init_data->constraints.boot_on || drvdata->enb_gpio)
331 return 0;
332
333 pwm_get_state(drvdata->pwm, &pstate);
334 if (pstate.enabled)
335 return 0;
336
337 /*
338 * Update the duty cycle so the output does not change
339 * when the regulator core enables the regulator (and
340 * thus the PWM channel).
341 */
342 if (pstate.polarity == PWM_POLARITY_INVERSED)
343 pstate.duty_cycle = pstate.period;
344 else
345 pstate.duty_cycle = 0;
346
347 return pwm_apply_might_sleep(drvdata->pwm, &pstate);
348 }
349
pwm_regulator_probe(struct platform_device * pdev)350 static int pwm_regulator_probe(struct platform_device *pdev)
351 {
352 const struct regulator_init_data *init_data;
353 struct pwm_regulator_data *drvdata;
354 struct regulator_dev *regulator;
355 struct regulator_config config = { };
356 struct device_node *np = pdev->dev.of_node;
357 enum gpiod_flags gpio_flags;
358 int ret;
359
360 if (!np)
361 return dev_err_probe(&pdev->dev, -EINVAL,
362 "Device Tree node missing\n");
363
364 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
365 if (!drvdata)
366 return -ENOMEM;
367
368 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
369
370 if (of_property_present(np, "voltage-table"))
371 ret = pwm_regulator_init_table(pdev, drvdata);
372 else
373 ret = pwm_regulator_init_continuous(pdev, drvdata);
374 if (ret)
375 return ret;
376
377 init_data = of_get_regulator_init_data(&pdev->dev, np,
378 &drvdata->desc);
379 if (!init_data)
380 return -ENOMEM;
381
382 config.of_node = np;
383 config.dev = &pdev->dev;
384 config.driver_data = drvdata;
385 config.init_data = init_data;
386
387 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
388 if (IS_ERR(drvdata->pwm))
389 return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->pwm),
390 "Failed to get PWM\n");
391
392 if (init_data->constraints.boot_on || init_data->constraints.always_on)
393 gpio_flags = GPIOD_OUT_HIGH;
394 else
395 gpio_flags = GPIOD_OUT_LOW;
396 drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
397 gpio_flags);
398 if (IS_ERR(drvdata->enb_gpio)) {
399 ret = PTR_ERR(drvdata->enb_gpio);
400 return dev_err_probe(&pdev->dev, ret, "Failed to get enable GPIO\n");
401 }
402
403 ret = pwm_adjust_config(drvdata->pwm);
404 if (ret)
405 return ret;
406
407 ret = pwm_regulator_init_boot_on(pdev, drvdata, init_data);
408 if (ret)
409 return dev_err_probe(&pdev->dev, ret,
410 "Failed to apply boot_on settings\n");
411
412 regulator = devm_regulator_register(&pdev->dev,
413 &drvdata->desc, &config);
414 if (IS_ERR(regulator)) {
415 ret = PTR_ERR(regulator);
416 return dev_err_probe(&pdev->dev, ret,
417 "Failed to register regulator %s\n",
418 drvdata->desc.name);
419 }
420
421 return 0;
422 }
423
424 static const struct of_device_id __maybe_unused pwm_of_match[] = {
425 { .compatible = "pwm-regulator" },
426 { },
427 };
428 MODULE_DEVICE_TABLE(of, pwm_of_match);
429
430 static struct platform_driver pwm_regulator_driver = {
431 .driver = {
432 .name = "pwm-regulator",
433 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
434 .of_match_table = of_match_ptr(pwm_of_match),
435 },
436 .probe = pwm_regulator_probe,
437 };
438
439 module_platform_driver(pwm_regulator_driver);
440
441 MODULE_LICENSE("GPL");
442 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
443 MODULE_DESCRIPTION("PWM Regulator Driver");
444 MODULE_ALIAS("platform:pwm-regulator");
445