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
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 /* Init voltage */
46 int init_uv;
47 };
48
49 struct pwm_voltages {
50 unsigned int uV;
51 unsigned int dutycycle;
52 };
53
54 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
55 int req_min_uV, int req_max_uV,
56 unsigned int *selector);
57
58 /*
59 * Voltage table call-backs
60 */
pwm_regulator_init_state(struct regulator_dev * rdev)61 static void pwm_regulator_init_state(struct regulator_dev *rdev)
62 {
63 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
64 struct pwm_state pwm_state;
65 unsigned int dutycycle;
66 int i;
67
68 pwm_get_state(drvdata->pwm, &pwm_state);
69 dutycycle = pwm_get_relative_duty_cycle(&pwm_state, 100);
70
71 for (i = 0; i < rdev->desc->n_voltages; i++) {
72 if (dutycycle == drvdata->duty_cycle_table[i].dutycycle) {
73 drvdata->state = i;
74 return;
75 }
76 }
77 }
78
pwm_regulator_get_voltage_sel(struct regulator_dev * rdev)79 static int pwm_regulator_get_voltage_sel(struct regulator_dev *rdev)
80 {
81 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
82
83 if (drvdata->state < 0)
84 pwm_regulator_init_state(rdev);
85
86 return drvdata->state;
87 }
88
pwm_regulator_set_voltage_sel(struct regulator_dev * rdev,unsigned selector)89 static int pwm_regulator_set_voltage_sel(struct regulator_dev *rdev,
90 unsigned selector)
91 {
92 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
93 struct pwm_state pstate;
94 int ret;
95
96 pwm_init_state(drvdata->pwm, &pstate);
97 pwm_set_relative_duty_cycle(&pstate,
98 drvdata->duty_cycle_table[selector].dutycycle, 100);
99
100 ret = pwm_apply_state(drvdata->pwm, &pstate);
101 if (ret) {
102 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
103 return ret;
104 }
105
106 drvdata->state = selector;
107
108 return 0;
109 }
110
pwm_regulator_list_voltage(struct regulator_dev * rdev,unsigned selector)111 static int pwm_regulator_list_voltage(struct regulator_dev *rdev,
112 unsigned selector)
113 {
114 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
115
116 if (selector >= rdev->desc->n_voltages)
117 return -EINVAL;
118
119 return drvdata->duty_cycle_table[selector].uV;
120 }
121
pwm_regulator_enable(struct regulator_dev * dev)122 static int pwm_regulator_enable(struct regulator_dev *dev)
123 {
124 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
125
126 if (drvdata->init_uv && !pwm_get_duty_cycle(drvdata->pwm))
127 pwm_regulator_set_voltage(dev, drvdata->init_uv,
128 drvdata->init_uv, NULL);
129
130 gpiod_set_value_cansleep(drvdata->enb_gpio, 1);
131
132 return pwm_enable(drvdata->pwm);
133 }
134
pwm_regulator_disable(struct regulator_dev * dev)135 static int pwm_regulator_disable(struct regulator_dev *dev)
136 {
137 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
138
139 pwm_disable(drvdata->pwm);
140
141 gpiod_set_value_cansleep(drvdata->enb_gpio, 0);
142
143 return 0;
144 }
145
pwm_regulator_is_enabled(struct regulator_dev * dev)146 static int pwm_regulator_is_enabled(struct regulator_dev *dev)
147 {
148 struct pwm_regulator_data *drvdata = rdev_get_drvdata(dev);
149
150 if (drvdata->enb_gpio && !gpiod_get_value_cansleep(drvdata->enb_gpio))
151 return false;
152
153 return pwm_is_enabled(drvdata->pwm);
154 }
155
pwm_regulator_get_voltage(struct regulator_dev * rdev)156 static int pwm_regulator_get_voltage(struct regulator_dev *rdev)
157 {
158 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
159 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
160 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
161 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
162 int min_uV = rdev->constraints->min_uV;
163 int max_uV = rdev->constraints->max_uV;
164 int diff_uV = max_uV - min_uV;
165 struct pwm_state pstate;
166 unsigned int diff_duty;
167 unsigned int voltage;
168
169 pwm_get_state(drvdata->pwm, &pstate);
170
171 voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
172
173 /*
174 * The dutycycle for min_uV might be greater than the one for max_uV.
175 * This is happening when the user needs an inversed polarity, but the
176 * PWM device does not support inversing it in hardware.
177 */
178 if (max_uV_duty < min_uV_duty) {
179 voltage = min_uV_duty - voltage;
180 diff_duty = min_uV_duty - max_uV_duty;
181 } else {
182 voltage = voltage - min_uV_duty;
183 diff_duty = max_uV_duty - min_uV_duty;
184 }
185
186 voltage = DIV_ROUND_CLOSEST_ULL((u64)voltage * diff_uV, diff_duty);
187
188 return voltage + min_uV;
189 }
190
pwm_regulator_set_voltage(struct regulator_dev * rdev,int req_min_uV,int req_max_uV,unsigned int * selector)191 static int pwm_regulator_set_voltage(struct regulator_dev *rdev,
192 int req_min_uV, int req_max_uV,
193 unsigned int *selector)
194 {
195 struct pwm_regulator_data *drvdata = rdev_get_drvdata(rdev);
196 unsigned int min_uV_duty = drvdata->continuous.min_uV_dutycycle;
197 unsigned int max_uV_duty = drvdata->continuous.max_uV_dutycycle;
198 unsigned int duty_unit = drvdata->continuous.dutycycle_unit;
199 int min_uV = rdev->constraints->min_uV;
200 int max_uV = rdev->constraints->max_uV;
201 int diff_uV = max_uV - min_uV;
202 struct pwm_state pstate;
203 unsigned int diff_duty;
204 unsigned int dutycycle;
205 int ret;
206
207 pwm_init_state(drvdata->pwm, &pstate);
208
209 /*
210 * The dutycycle for min_uV might be greater than the one for max_uV.
211 * This is happening when the user needs an inversed polarity, but the
212 * PWM device does not support inversing it in hardware.
213 */
214 if (max_uV_duty < min_uV_duty)
215 diff_duty = min_uV_duty - max_uV_duty;
216 else
217 diff_duty = max_uV_duty - min_uV_duty;
218
219 dutycycle = DIV_ROUND_CLOSEST_ULL((u64)(req_min_uV - min_uV) *
220 diff_duty,
221 diff_uV);
222
223 if (max_uV_duty < min_uV_duty)
224 dutycycle = min_uV_duty - dutycycle;
225 else
226 dutycycle = min_uV_duty + dutycycle;
227
228 pwm_set_relative_duty_cycle(&pstate, dutycycle, duty_unit);
229
230 ret = pwm_apply_state(drvdata->pwm, &pstate);
231 if (ret) {
232 dev_err(&rdev->dev, "Failed to configure PWM: %d\n", ret);
233 return ret;
234 }
235
236 return 0;
237 }
238
239 static const struct regulator_ops pwm_regulator_voltage_table_ops = {
240 .set_voltage_sel = pwm_regulator_set_voltage_sel,
241 .get_voltage_sel = pwm_regulator_get_voltage_sel,
242 .list_voltage = pwm_regulator_list_voltage,
243 .map_voltage = regulator_map_voltage_iterate,
244 .enable = pwm_regulator_enable,
245 .disable = pwm_regulator_disable,
246 .is_enabled = pwm_regulator_is_enabled,
247 };
248
249 static const struct regulator_ops pwm_regulator_voltage_continuous_ops = {
250 .get_voltage = pwm_regulator_get_voltage,
251 .set_voltage = pwm_regulator_set_voltage,
252 .enable = pwm_regulator_enable,
253 .disable = pwm_regulator_disable,
254 .is_enabled = pwm_regulator_is_enabled,
255 };
256
257 static const struct regulator_desc pwm_regulator_desc = {
258 .name = "pwm-regulator",
259 .type = REGULATOR_VOLTAGE,
260 .owner = THIS_MODULE,
261 .supply_name = "pwm",
262 };
263
pwm_regulator_init_table(struct platform_device * pdev,struct pwm_regulator_data * drvdata)264 static int pwm_regulator_init_table(struct platform_device *pdev,
265 struct pwm_regulator_data *drvdata)
266 {
267 struct device_node *np = pdev->dev.of_node;
268 struct pwm_voltages *duty_cycle_table;
269 unsigned int length = 0;
270 int ret;
271
272 of_find_property(np, "voltage-table", &length);
273
274 if ((length < sizeof(*duty_cycle_table)) ||
275 (length % sizeof(*duty_cycle_table))) {
276 dev_err(&pdev->dev, "voltage-table length(%d) is invalid\n",
277 length);
278 return -EINVAL;
279 }
280
281 duty_cycle_table = devm_kzalloc(&pdev->dev, length, GFP_KERNEL);
282 if (!duty_cycle_table)
283 return -ENOMEM;
284
285 ret = of_property_read_u32_array(np, "voltage-table",
286 (u32 *)duty_cycle_table,
287 length / sizeof(u32));
288 if (ret) {
289 dev_err(&pdev->dev, "Failed to read voltage-table: %d\n", ret);
290 return ret;
291 }
292
293 drvdata->state = -ENOTRECOVERABLE;
294 drvdata->duty_cycle_table = duty_cycle_table;
295 drvdata->desc.ops = &pwm_regulator_voltage_table_ops;
296 drvdata->desc.n_voltages = length / sizeof(*duty_cycle_table);
297
298 return 0;
299 }
300
pwm_regulator_init_continuous(struct platform_device * pdev,struct pwm_regulator_data * drvdata)301 static int pwm_regulator_init_continuous(struct platform_device *pdev,
302 struct pwm_regulator_data *drvdata)
303 {
304 u32 dutycycle_range[2] = { 0, 100 };
305 u32 dutycycle_unit = 100;
306
307 drvdata->desc.ops = &pwm_regulator_voltage_continuous_ops;
308 drvdata->desc.continuous_voltage_range = true;
309
310 of_property_read_u32_array(pdev->dev.of_node,
311 "pwm-dutycycle-range",
312 dutycycle_range, 2);
313 of_property_read_u32(pdev->dev.of_node, "pwm-dutycycle-unit",
314 &dutycycle_unit);
315
316 if (dutycycle_range[0] > dutycycle_unit ||
317 dutycycle_range[1] > dutycycle_unit)
318 return -EINVAL;
319
320 drvdata->continuous.dutycycle_unit = dutycycle_unit;
321 drvdata->continuous.min_uV_dutycycle = dutycycle_range[0];
322 drvdata->continuous.max_uV_dutycycle = dutycycle_range[1];
323
324 return 0;
325 }
326
pwm_regulator_probe(struct platform_device * pdev)327 static int pwm_regulator_probe(struct platform_device *pdev)
328 {
329 const struct regulator_init_data *init_data;
330 struct pwm_regulator_data *drvdata;
331 struct regulator_dev *regulator;
332 struct regulator_config config = { };
333 struct device_node *np = pdev->dev.of_node;
334 enum gpiod_flags gpio_flags;
335 int ret;
336 u32 init_uv;
337
338 if (!np) {
339 dev_err(&pdev->dev, "Device Tree node missing\n");
340 return -EINVAL;
341 }
342
343 drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
344 if (!drvdata)
345 return -ENOMEM;
346
347 memcpy(&drvdata->desc, &pwm_regulator_desc, sizeof(drvdata->desc));
348
349 if (of_find_property(np, "voltage-table", NULL))
350 ret = pwm_regulator_init_table(pdev, drvdata);
351 else
352 ret = pwm_regulator_init_continuous(pdev, drvdata);
353 if (ret)
354 return ret;
355
356 if (!of_property_read_u32(np, "regulator-init-microvolt", &init_uv))
357 drvdata->init_uv = init_uv;
358
359 init_data = of_get_regulator_init_data(&pdev->dev, np,
360 &drvdata->desc);
361 if (!init_data)
362 return -ENOMEM;
363
364 config.of_node = np;
365 config.dev = &pdev->dev;
366 config.driver_data = drvdata;
367 config.init_data = init_data;
368
369 drvdata->pwm = devm_pwm_get(&pdev->dev, NULL);
370 if (IS_ERR(drvdata->pwm)) {
371 ret = PTR_ERR(drvdata->pwm);
372 if (ret == -EPROBE_DEFER)
373 dev_dbg(&pdev->dev,
374 "Failed to get PWM, deferring probe\n");
375 else
376 dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
377 return ret;
378 }
379
380 if (init_data->constraints.boot_on || init_data->constraints.always_on)
381 gpio_flags = GPIOD_OUT_HIGH;
382 else
383 gpio_flags = GPIOD_OUT_LOW;
384 drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
385 gpio_flags);
386 if (IS_ERR(drvdata->enb_gpio)) {
387 ret = PTR_ERR(drvdata->enb_gpio);
388 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
389 return ret;
390 }
391
392 ret = pwm_adjust_config(drvdata->pwm);
393 if (ret)
394 return ret;
395
396 regulator = devm_regulator_register(&pdev->dev,
397 &drvdata->desc, &config);
398 if (IS_ERR(regulator)) {
399 ret = PTR_ERR(regulator);
400 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
401 drvdata->desc.name, ret);
402 return ret;
403 }
404
405 return 0;
406 }
407
408 static const struct of_device_id __maybe_unused pwm_of_match[] = {
409 { .compatible = "pwm-regulator" },
410 { },
411 };
412 MODULE_DEVICE_TABLE(of, pwm_of_match);
413
414 static struct platform_driver pwm_regulator_driver = {
415 .driver = {
416 .name = "pwm-regulator",
417 .of_match_table = of_match_ptr(pwm_of_match),
418 },
419 .probe = pwm_regulator_probe,
420 };
421
422 module_platform_driver(pwm_regulator_driver);
423
424 MODULE_LICENSE("GPL");
425 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
426 MODULE_DESCRIPTION("PWM Regulator Driver");
427 MODULE_ALIAS("platform:pwm-regulator");
428