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 (config->init_data->constraints.boot_on)
152 		config->enabled_at_boot = true;
153 
154 	/*
155 	 * Do not use: undocumented device tree property.
156 	 * This is kept around solely for device tree ABI stability.
157 	 */
158 	if (of_property_read_bool(np, "enable-at-boot"))
159 		config->enabled_at_boot = true;
160 
161 	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
162 
163 	/* Fetch GPIO init levels */
164 	ngpios = gpiod_count(dev, NULL);
165 	if (ngpios > 0) {
166 		config->gflags = devm_kzalloc(dev,
167 					      sizeof(enum gpiod_flags)
168 					      * ngpios,
169 					      GFP_KERNEL);
170 		if (!config->gflags)
171 			return ERR_PTR(-ENOMEM);
172 
173 		for (i = 0; i < ngpios; i++) {
174 			u32 val;
175 
176 			ret = of_property_read_u32_index(np, "gpios-states", i,
177 							 &val);
178 
179 			/* Default to high per specification */
180 			if (ret)
181 				config->gflags[i] = GPIOD_OUT_HIGH;
182 			else
183 				config->gflags[i] =
184 					val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
185 		}
186 	}
187 	config->ngpios = ngpios;
188 
189 	/* Fetch states. */
190 	proplen = of_property_count_u32_elems(np, "states");
191 	if (proplen < 0) {
192 		dev_err(dev, "No 'states' property found\n");
193 		return ERR_PTR(-EINVAL);
194 	}
195 
196 	config->states = devm_kcalloc(dev,
197 				proplen / 2,
198 				sizeof(struct gpio_regulator_state),
199 				GFP_KERNEL);
200 	if (!config->states)
201 		return ERR_PTR(-ENOMEM);
202 
203 	for (i = 0; i < proplen / 2; i++) {
204 		of_property_read_u32_index(np, "states", i * 2,
205 					   &config->states[i].value);
206 		of_property_read_u32_index(np, "states", i * 2 + 1,
207 					   &config->states[i].gpios);
208 	}
209 	config->nr_states = i;
210 
211 	config->type = REGULATOR_VOLTAGE;
212 	ret = of_property_read_string(np, "regulator-type", &regtype);
213 	if (ret >= 0) {
214 		if (!strncmp("voltage", regtype, 7))
215 			config->type = REGULATOR_VOLTAGE;
216 		else if (!strncmp("current", regtype, 7))
217 			config->type = REGULATOR_CURRENT;
218 		else
219 			dev_warn(dev, "Unknown regulator-type '%s'\n",
220 				 regtype);
221 	}
222 
223 	if (of_property_present(np, "vin-supply"))
224 		config->input_supply = "vin";
225 
226 	return config;
227 }
228 
229 static const struct regulator_ops gpio_regulator_current_ops = {
230 	.get_current_limit = gpio_regulator_get_value,
231 	.set_current_limit = gpio_regulator_set_current_limit,
232 };
233 
234 static int gpio_regulator_probe(struct platform_device *pdev)
235 {
236 	struct device *dev = &pdev->dev;
237 	struct gpio_regulator_config *config = dev_get_platdata(dev);
238 	struct device_node *np = dev->of_node;
239 	struct gpio_regulator_data *drvdata;
240 	struct regulator_config cfg = { };
241 	struct regulator_dev *rdev;
242 	enum gpiod_flags gflags;
243 	int ptr, ret, state, i;
244 
245 	drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
246 			       GFP_KERNEL);
247 	if (drvdata == NULL)
248 		return -ENOMEM;
249 
250 	if (np) {
251 		config = of_get_gpio_regulator_config(dev, np,
252 						      &drvdata->desc);
253 		if (IS_ERR(config))
254 			return PTR_ERR(config);
255 	}
256 
257 	drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
258 	if (drvdata->desc.name == NULL) {
259 		dev_err(dev, "Failed to allocate supply name\n");
260 		return -ENOMEM;
261 	}
262 
263 	drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
264 				       GFP_KERNEL);
265 
266 	if (config->input_supply) {
267 		drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
268 							 config->input_supply,
269 							 GFP_KERNEL);
270 		if (!drvdata->desc.supply_name) {
271 			dev_err(&pdev->dev,
272 				"Failed to allocate input supply\n");
273 			return -ENOMEM;
274 		}
275 	}
276 
277 	if (!drvdata->gpiods)
278 		return -ENOMEM;
279 	for (i = 0; i < config->ngpios; i++) {
280 		drvdata->gpiods[i] = devm_gpiod_get_index(dev,
281 							  NULL,
282 							  i,
283 							  config->gflags[i]);
284 		if (IS_ERR(drvdata->gpiods[i]))
285 			return PTR_ERR(drvdata->gpiods[i]);
286 		/* This is good to know */
287 		gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
288 	}
289 	drvdata->nr_gpios = config->ngpios;
290 
291 	drvdata->states = devm_kmemdup(dev,
292 				       config->states,
293 				       config->nr_states *
294 				       sizeof(struct gpio_regulator_state),
295 				       GFP_KERNEL);
296 	if (drvdata->states == NULL) {
297 		dev_err(dev, "Failed to allocate state data\n");
298 		return -ENOMEM;
299 	}
300 	drvdata->nr_states = config->nr_states;
301 
302 	drvdata->desc.owner = THIS_MODULE;
303 	drvdata->desc.enable_time = config->startup_delay;
304 
305 	/* handle regulator type*/
306 	switch (config->type) {
307 	case REGULATOR_VOLTAGE:
308 		drvdata->desc.type = REGULATOR_VOLTAGE;
309 		drvdata->desc.ops = &gpio_regulator_voltage_ops;
310 		drvdata->desc.n_voltages = config->nr_states;
311 		break;
312 	case REGULATOR_CURRENT:
313 		drvdata->desc.type = REGULATOR_CURRENT;
314 		drvdata->desc.ops = &gpio_regulator_current_ops;
315 		break;
316 	default:
317 		dev_err(dev, "No regulator type set\n");
318 		return -EINVAL;
319 	}
320 
321 	/* build initial state from gpio init data. */
322 	state = 0;
323 	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
324 		if (config->gflags[ptr] == GPIOD_OUT_HIGH)
325 			state |= (1 << ptr);
326 	}
327 	drvdata->state = state;
328 
329 	cfg.dev = dev;
330 	cfg.init_data = config->init_data;
331 	cfg.driver_data = drvdata;
332 	cfg.of_node = np;
333 
334 	/*
335 	 * The signal will be inverted by the GPIO core if flagged so in the
336 	 * descriptor.
337 	 */
338 	if (config->enabled_at_boot)
339 		gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
340 	else
341 		gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
342 
343 	cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
344 	if (IS_ERR(cfg.ena_gpiod))
345 		return PTR_ERR(cfg.ena_gpiod);
346 
347 	rdev = devm_regulator_register(dev, &drvdata->desc, &cfg);
348 	if (IS_ERR(rdev)) {
349 		ret = PTR_ERR(rdev);
350 		dev_err(dev, "Failed to register regulator: %d\n", ret);
351 		return ret;
352 	}
353 
354 	platform_set_drvdata(pdev, drvdata);
355 
356 	return 0;
357 }
358 
359 #if defined(CONFIG_OF)
360 static const struct of_device_id regulator_gpio_of_match[] = {
361 	{ .compatible = "regulator-gpio", },
362 	{},
363 };
364 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
365 #endif
366 
367 static struct platform_driver gpio_regulator_driver = {
368 	.probe		= gpio_regulator_probe,
369 	.driver		= {
370 		.name		= "gpio-regulator",
371 		.probe_type	= PROBE_PREFER_ASYNCHRONOUS,
372 		.of_match_table = of_match_ptr(regulator_gpio_of_match),
373 	},
374 };
375 
376 static int __init gpio_regulator_init(void)
377 {
378 	return platform_driver_register(&gpio_regulator_driver);
379 }
380 subsys_initcall(gpio_regulator_init);
381 
382 static void __exit gpio_regulator_exit(void)
383 {
384 	platform_driver_unregister(&gpio_regulator_driver);
385 }
386 module_exit(gpio_regulator_exit);
387 
388 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
389 MODULE_DESCRIPTION("gpio voltage regulator");
390 MODULE_LICENSE("GPL");
391 MODULE_ALIAS("platform:gpio-regulator");
392