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
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_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
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	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
190static 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
238static 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
248static 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
256static 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
263static 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
298static 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
324static 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
350static 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
424static const struct of_device_id __maybe_unused pwm_of_match[] = {
425	{ .compatible = "pwm-regulator" },
426	{ },
427};
428MODULE_DEVICE_TABLE(of, pwm_of_match);
429
430static 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
439module_platform_driver(pwm_regulator_driver);
440
441MODULE_LICENSE("GPL");
442MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
443MODULE_DESCRIPTION("PWM Regulator Driver");
444MODULE_ALIAS("platform:pwm-regulator");
445