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 voltage = pwm_get_relative_duty_cycle(&pstate, duty_unit);
161 if (voltage < min(max_uV_duty, min_uV_duty) ||
162 voltage > max(max_uV_duty, min_uV_duty))
163 return -ENOTRECOVERABLE;
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
pwm_regulator_set_voltage(struct regulator_dev * rdev,int req_min_uV,int req_max_uV,unsigned int * selector)183 static 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_might_sleep(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
231 static 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
241 static 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
249 static 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
pwm_regulator_init_table(struct platform_device * pdev,struct pwm_regulator_data * drvdata)256 static 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 = -ENOTRECOVERABLE;
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
pwm_regulator_init_continuous(struct platform_device * pdev,struct pwm_regulator_data * drvdata)293 static 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
pwm_regulator_probe(struct platform_device * pdev)319 static 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_property_present(np, "voltage-table"))
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 return dev_err_probe(&pdev->dev, PTR_ERR(drvdata->pwm),
360 "Failed to get PWM\n");
361
362 if (init_data->constraints.boot_on || init_data->constraints.always_on)
363 gpio_flags = GPIOD_OUT_HIGH;
364 else
365 gpio_flags = GPIOD_OUT_LOW;
366 drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
367 gpio_flags);
368 if (IS_ERR(drvdata->enb_gpio)) {
369 ret = PTR_ERR(drvdata->enb_gpio);
370 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
371 return ret;
372 }
373
374 ret = pwm_adjust_config(drvdata->pwm);
375 if (ret)
376 return ret;
377
378 regulator = devm_regulator_register(&pdev->dev,
379 &drvdata->desc, &config);
380 if (IS_ERR(regulator)) {
381 ret = PTR_ERR(regulator);
382 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
383 drvdata->desc.name, ret);
384 return ret;
385 }
386
387 return 0;
388 }
389
390 static const struct of_device_id __maybe_unused pwm_of_match[] = {
391 { .compatible = "pwm-regulator" },
392 { },
393 };
394 MODULE_DEVICE_TABLE(of, pwm_of_match);
395
396 static struct platform_driver pwm_regulator_driver = {
397 .driver = {
398 .name = "pwm-regulator",
399 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
400 .of_match_table = of_match_ptr(pwm_of_match),
401 },
402 .probe = pwm_regulator_probe,
403 };
404
405 module_platform_driver(pwm_regulator_driver);
406
407 MODULE_LICENSE("GPL");
408 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
409 MODULE_DESCRIPTION("PWM Regulator Driver");
410 MODULE_ALIAS("platform:pwm-regulator");
411