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_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
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	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
183static 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
231static 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
241static 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
249static 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
256static 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
293static 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
319static 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
390static const struct of_device_id __maybe_unused pwm_of_match[] = {
391	{ .compatible = "pwm-regulator" },
392	{ },
393};
394MODULE_DEVICE_TABLE(of, pwm_of_match);
395
396static 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
405module_platform_driver(pwm_regulator_driver);
406
407MODULE_LICENSE("GPL");
408MODULE_AUTHOR("Lee Jones <lee.jones@linaro.org>");
409MODULE_DESCRIPTION("PWM Regulator Driver");
410MODULE_ALIAS("platform:pwm-regulator");
411