1// SPDX-License-Identifier: GPL-2.0-or-later
  2/*
  3 * gpio-regulator.c
  4 *
  5 * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
  6 *
  7 * based on fixed.c
  8 *
  9 * Copyright 2008 Wolfson Microelectronics PLC.
 10 *
 11 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 12 *
 13 * Copyright (c) 2009 Nokia Corporation
 14 * Roger Quadros <ext-roger.quadros@nokia.com>
 15 *
 16 * This is useful for systems with mixed controllable and
 17 * non-controllable regulators, as well as for allowing testing on
 18 * systems with no controllable regulators.
 19 */
 20
 21#include <linux/err.h>
 22#include <linux/mutex.h>
 23#include <linux/module.h>
 24#include <linux/platform_device.h>
 25#include <linux/regulator/driver.h>
 26#include <linux/regulator/machine.h>
 27#include <linux/regulator/of_regulator.h>
 28#include <linux/regulator/gpio-regulator.h>
 29#include <linux/gpio/consumer.h>
 30#include <linux/slab.h>
 31#include <linux/of.h>
 32
 33struct gpio_regulator_data {
 34	struct regulator_desc desc;
 35
 36	struct gpio_desc **gpiods;
 37	int nr_gpios;
 38
 39	struct gpio_regulator_state *states;
 40	int nr_states;
 41
 42	int state;
 43};
 44
 45static int gpio_regulator_get_value(struct regulator_dev *dev)
 46{
 47	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 48	int ptr;
 49
 50	for (ptr = 0; ptr < data->nr_states; ptr++)
 51		if (data->states[ptr].gpios == data->state)
 52			return data->states[ptr].value;
 53
 54	return -EINVAL;
 55}
 56
 57static int gpio_regulator_set_voltage(struct regulator_dev *dev,
 58					int min_uV, int max_uV,
 59					unsigned *selector)
 60{
 61	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 62	int ptr, target = 0, state, best_val = INT_MAX;
 63
 64	for (ptr = 0; ptr < data->nr_states; ptr++)
 65		if (data->states[ptr].value < best_val &&
 66		    data->states[ptr].value >= min_uV &&
 67		    data->states[ptr].value <= max_uV) {
 68			target = data->states[ptr].gpios;
 69			best_val = data->states[ptr].value;
 70			if (selector)
 71				*selector = ptr;
 72		}
 73
 74	if (best_val == INT_MAX)
 75		return -EINVAL;
 76
 77	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
 78		state = (target & (1 << ptr)) >> ptr;
 79		gpiod_set_value_cansleep(data->gpiods[ptr], state);
 80	}
 81	data->state = target;
 82
 83	return 0;
 84}
 85
 86static int gpio_regulator_list_voltage(struct regulator_dev *dev,
 87				      unsigned selector)
 88{
 89	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 90
 91	if (selector >= data->nr_states)
 92		return -EINVAL;
 93
 94	return data->states[selector].value;
 95}
 96
 97static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
 98					int min_uA, int max_uA)
 99{
100	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
101	int ptr, target = 0, state, best_val = 0;
102
103	for (ptr = 0; ptr < data->nr_states; ptr++)
104		if (data->states[ptr].value > best_val &&
105		    data->states[ptr].value >= min_uA &&
106		    data->states[ptr].value <= max_uA) {
107			target = data->states[ptr].gpios;
108			best_val = data->states[ptr].value;
109		}
110
111	if (best_val == 0)
112		return -EINVAL;
113
114	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
115		state = (target & (1 << ptr)) >> ptr;
116		gpiod_set_value_cansleep(data->gpiods[ptr], state);
117	}
118	data->state = target;
119
120	return 0;
121}
122
123static const struct regulator_ops gpio_regulator_voltage_ops = {
124	.get_voltage = gpio_regulator_get_value,
125	.set_voltage = gpio_regulator_set_voltage,
126	.list_voltage = gpio_regulator_list_voltage,
127};
128
129static struct gpio_regulator_config *
130of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
131			     const struct regulator_desc *desc)
132{
133	struct gpio_regulator_config *config;
134	const char *regtype;
135	int proplen, i;
136	int ngpios;
137	int ret;
138
139	config = devm_kzalloc(dev,
140			sizeof(struct gpio_regulator_config),
141			GFP_KERNEL);
142	if (!config)
143		return ERR_PTR(-ENOMEM);
144
145	config->init_data = of_get_regulator_init_data(dev, np, desc);
146	if (!config->init_data)
147		return ERR_PTR(-EINVAL);
148
149	config->supply_name = config->init_data->constraints.name;
150
151	if (of_property_read_bool(np, "enable-at-boot"))
152		config->enabled_at_boot = true;
153
154	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
155
156	/* Fetch GPIO init levels */
157	ngpios = gpiod_count(dev, NULL);
158	if (ngpios > 0) {
159		config->gflags = devm_kzalloc(dev,
160					      sizeof(enum gpiod_flags)
161					      * ngpios,
162					      GFP_KERNEL);
163		if (!config->gflags)
164			return ERR_PTR(-ENOMEM);
165
166		for (i = 0; i < ngpios; i++) {
167			u32 val;
168
169			ret = of_property_read_u32_index(np, "gpios-states", i,
170							 &val);
171
172			/* Default to high per specification */
173			if (ret)
174				config->gflags[i] = GPIOD_OUT_HIGH;
175			else
176				config->gflags[i] =
177					val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
178		}
179	}
180	config->ngpios = ngpios;
181
182	/* Fetch states. */
183	proplen = of_property_count_u32_elems(np, "states");
184	if (proplen < 0) {
185		dev_err(dev, "No 'states' property found\n");
186		return ERR_PTR(-EINVAL);
187	}
188
189	config->states = devm_kcalloc(dev,
190				proplen / 2,
191				sizeof(struct gpio_regulator_state),
192				GFP_KERNEL);
193	if (!config->states)
194		return ERR_PTR(-ENOMEM);
195
196	for (i = 0; i < proplen / 2; i++) {
197		of_property_read_u32_index(np, "states", i * 2,
198					   &config->states[i].value);
199		of_property_read_u32_index(np, "states", i * 2 + 1,
200					   &config->states[i].gpios);
201	}
202	config->nr_states = i;
203
204	config->type = REGULATOR_VOLTAGE;
205	ret = of_property_read_string(np, "regulator-type", &regtype);
206	if (ret >= 0) {
207		if (!strncmp("voltage", regtype, 7))
208			config->type = REGULATOR_VOLTAGE;
209		else if (!strncmp("current", regtype, 7))
210			config->type = REGULATOR_CURRENT;
211		else
212			dev_warn(dev, "Unknown regulator-type '%s'\n",
213				 regtype);
214	}
215
216	return config;
217}
218
219static const struct regulator_ops gpio_regulator_current_ops = {
220	.get_current_limit = gpio_regulator_get_value,
221	.set_current_limit = gpio_regulator_set_current_limit,
222};
223
224static int gpio_regulator_probe(struct platform_device *pdev)
225{
226	struct device *dev = &pdev->dev;
227	struct gpio_regulator_config *config = dev_get_platdata(dev);
228	struct device_node *np = dev->of_node;
229	struct gpio_regulator_data *drvdata;
230	struct regulator_config cfg = { };
231	struct regulator_dev *rdev;
232	enum gpiod_flags gflags;
233	int ptr, ret, state, i;
234
235	drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
236			       GFP_KERNEL);
237	if (drvdata == NULL)
238		return -ENOMEM;
239
240	if (np) {
241		config = of_get_gpio_regulator_config(dev, np,
242						      &drvdata->desc);
243		if (IS_ERR(config))
244			return PTR_ERR(config);
245	}
246
247	drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
248	if (drvdata->desc.name == NULL) {
249		dev_err(dev, "Failed to allocate supply name\n");
250		return -ENOMEM;
251	}
252
253	drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
254				       GFP_KERNEL);
255	if (!drvdata->gpiods)
256		return -ENOMEM;
257	for (i = 0; i < config->ngpios; i++) {
258		drvdata->gpiods[i] = devm_gpiod_get_index(dev,
259							  NULL,
260							  i,
261							  config->gflags[i]);
262		if (IS_ERR(drvdata->gpiods[i]))
263			return PTR_ERR(drvdata->gpiods[i]);
264		/* This is good to know */
265		gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
266	}
267	drvdata->nr_gpios = config->ngpios;
268
269	drvdata->states = devm_kmemdup(dev,
270				       config->states,
271				       config->nr_states *
272				       sizeof(struct gpio_regulator_state),
273				       GFP_KERNEL);
274	if (drvdata->states == NULL) {
275		dev_err(dev, "Failed to allocate state data\n");
276		return -ENOMEM;
277	}
278	drvdata->nr_states = config->nr_states;
279
280	drvdata->desc.owner = THIS_MODULE;
281	drvdata->desc.enable_time = config->startup_delay;
282
283	/* handle regulator type*/
284	switch (config->type) {
285	case REGULATOR_VOLTAGE:
286		drvdata->desc.type = REGULATOR_VOLTAGE;
287		drvdata->desc.ops = &gpio_regulator_voltage_ops;
288		drvdata->desc.n_voltages = config->nr_states;
289		break;
290	case REGULATOR_CURRENT:
291		drvdata->desc.type = REGULATOR_CURRENT;
292		drvdata->desc.ops = &gpio_regulator_current_ops;
293		break;
294	default:
295		dev_err(dev, "No regulator type set\n");
296		return -EINVAL;
297	}
298
299	/* build initial state from gpio init data. */
300	state = 0;
301	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
302		if (config->gflags[ptr] == GPIOD_OUT_HIGH)
303			state |= (1 << ptr);
304	}
305	drvdata->state = state;
306
307	cfg.dev = dev;
308	cfg.init_data = config->init_data;
309	cfg.driver_data = drvdata;
310	cfg.of_node = np;
311
312	/*
313	 * The signal will be inverted by the GPIO core if flagged so in the
314	 * decriptor.
315	 */
316	if (config->enabled_at_boot)
317		gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
318	else
319		gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
320
321	cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
322	if (IS_ERR(cfg.ena_gpiod))
323		return PTR_ERR(cfg.ena_gpiod);
324
325	rdev = devm_regulator_register(dev, &drvdata->desc, &cfg);
326	if (IS_ERR(rdev)) {
327		ret = PTR_ERR(rdev);
328		dev_err(dev, "Failed to register regulator: %d\n", ret);
329		return ret;
330	}
331
332	platform_set_drvdata(pdev, drvdata);
333
334	return 0;
335}
336
337#if defined(CONFIG_OF)
338static const struct of_device_id regulator_gpio_of_match[] = {
339	{ .compatible = "regulator-gpio", },
340	{},
341};
342MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
343#endif
344
345static struct platform_driver gpio_regulator_driver = {
346	.probe		= gpio_regulator_probe,
347	.driver		= {
348		.name		= "gpio-regulator",
349		.of_match_table = of_match_ptr(regulator_gpio_of_match),
350	},
351};
352
353static int __init gpio_regulator_init(void)
354{
355	return platform_driver_register(&gpio_regulator_driver);
356}
357subsys_initcall(gpio_regulator_init);
358
359static void __exit gpio_regulator_exit(void)
360{
361	platform_driver_unregister(&gpio_regulator_driver);
362}
363module_exit(gpio_regulator_exit);
364
365MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
366MODULE_DESCRIPTION("gpio voltage regulator");
367MODULE_LICENSE("GPL");
368MODULE_ALIAS("platform:gpio-regulator");