GNU Linux-libre 5.10.219-gnu1
[releases.git] / drivers / regulator / pwm-regulator.c
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
46 struct pwm_voltages {
47         unsigned int uV;
48         unsigned int dutycycle;
49 };
50
51 /*
52  * Voltage table call-backs
53  */
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
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
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_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
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
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
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
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
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
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_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
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
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
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
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_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                 if (ret == -EPROBE_DEFER)
361                         dev_dbg(&pdev->dev,
362                                 "Failed to get PWM, deferring probe\n");
363                 else
364                         dev_err(&pdev->dev, "Failed to get PWM: %d\n", ret);
365                 return ret;
366         }
367
368         if (init_data->constraints.boot_on || init_data->constraints.always_on)
369                 gpio_flags = GPIOD_OUT_HIGH;
370         else
371                 gpio_flags = GPIOD_OUT_LOW;
372         drvdata->enb_gpio = devm_gpiod_get_optional(&pdev->dev, "enable",
373                                                     gpio_flags);
374         if (IS_ERR(drvdata->enb_gpio)) {
375                 ret = PTR_ERR(drvdata->enb_gpio);
376                 dev_err(&pdev->dev, "Failed to get enable GPIO: %d\n", ret);
377                 return ret;
378         }
379
380         ret = pwm_adjust_config(drvdata->pwm);
381         if (ret)
382                 return ret;
383
384         regulator = devm_regulator_register(&pdev->dev,
385                                             &drvdata->desc, &config);
386         if (IS_ERR(regulator)) {
387                 ret = PTR_ERR(regulator);
388                 dev_err(&pdev->dev, "Failed to register regulator %s: %d\n",
389                         drvdata->desc.name, ret);
390                 return ret;
391         }
392
393         return 0;
394 }
395
396 static const struct of_device_id __maybe_unused pwm_of_match[] = {
397         { .compatible = "pwm-regulator" },
398         { },
399 };
400 MODULE_DEVICE_TABLE(of, pwm_of_match);
401
402 static struct platform_driver pwm_regulator_driver = {
403         .driver = {
404                 .name           = "pwm-regulator",
405                 .of_match_table = of_match_ptr(pwm_of_match),
406         },
407         .probe = pwm_regulator_probe,
408 };
409
410 module_platform_driver(pwm_regulator_driver);
411
412 MODULE_LICENSE("GPL");
413 MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
414 MODULE_DESCRIPTION("PWM Regulator Driver");
415 MODULE_ALIAS("platform:pwm-regulator");