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 
33 struct 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 
45 static 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 
57 static 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 
86 static 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 
97 static 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 
123 static 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 
129 static struct gpio_regulator_config *
130 of_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 
219 static 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 
224 static 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)
338 static const struct of_device_id regulator_gpio_of_match[] = {
339 	{ .compatible = "regulator-gpio", },
340 	{},
341 };
342 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
343 #endif
344 
345 static 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 
353 static int __init gpio_regulator_init(void)
354 {
355 	return platform_driver_register(&gpio_regulator_driver);
356 }
357 subsys_initcall(gpio_regulator_init);
358 
359 static void __exit gpio_regulator_exit(void)
360 {
361 	platform_driver_unregister(&gpio_regulator_driver);
362 }
363 module_exit(gpio_regulator_exit);
364 
365 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
366 MODULE_DESCRIPTION("gpio voltage regulator");
367 MODULE_LICENSE("GPL");
368 MODULE_ALIAS("platform:gpio-regulator");
369