1 /*
2  * gpio-regulator.c
3  *
4  * Copyright 2011 Heiko Stuebner <heiko@sntech.de>
5  *
6  * based on fixed.c
7  *
8  * Copyright 2008 Wolfson Microelectronics PLC.
9  *
10  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
11  *
12  * Copyright (c) 2009 Nokia Corporation
13  * Roger Quadros <ext-roger.quadros@nokia.com>
14  *
15  * This program is free software; you can redistribute it and/or
16  * modify it under the terms of the GNU General Public License as
17  * published by the Free Software Foundation; either version 2 of the
18  * License, or (at your option) any later version.
19  *
20  * This is useful for systems with mixed controllable and
21  * non-controllable regulators, as well as for allowing testing on
22  * systems with no controllable regulators.
23  */
24 
25 #include <linux/err.h>
26 #include <linux/mutex.h>
27 #include <linux/module.h>
28 #include <linux/platform_device.h>
29 #include <linux/regulator/driver.h>
30 #include <linux/regulator/machine.h>
31 #include <linux/regulator/of_regulator.h>
32 #include <linux/regulator/gpio-regulator.h>
33 #include <linux/gpio/consumer.h>
34 #include <linux/slab.h>
35 #include <linux/of.h>
36 
37 struct gpio_regulator_data {
38 	struct regulator_desc desc;
39 	struct regulator_dev *dev;
40 
41 	struct gpio_desc **gpiods;
42 	int nr_gpios;
43 
44 	struct gpio_regulator_state *states;
45 	int nr_states;
46 
47 	int state;
48 };
49 
50 static int gpio_regulator_get_value(struct regulator_dev *dev)
51 {
52 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
53 	int ptr;
54 
55 	for (ptr = 0; ptr < data->nr_states; ptr++)
56 		if (data->states[ptr].gpios == data->state)
57 			return data->states[ptr].value;
58 
59 	return -EINVAL;
60 }
61 
62 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
63 					int min_uV, int max_uV,
64 					unsigned *selector)
65 {
66 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
67 	int ptr, target = 0, state, best_val = INT_MAX;
68 
69 	for (ptr = 0; ptr < data->nr_states; ptr++)
70 		if (data->states[ptr].value < best_val &&
71 		    data->states[ptr].value >= min_uV &&
72 		    data->states[ptr].value <= max_uV) {
73 			target = data->states[ptr].gpios;
74 			best_val = data->states[ptr].value;
75 			if (selector)
76 				*selector = ptr;
77 		}
78 
79 	if (best_val == INT_MAX)
80 		return -EINVAL;
81 
82 	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
83 		state = (target & (1 << ptr)) >> ptr;
84 		gpiod_set_value_cansleep(data->gpiods[ptr], state);
85 	}
86 	data->state = target;
87 
88 	return 0;
89 }
90 
91 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
92 				      unsigned selector)
93 {
94 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
95 
96 	if (selector >= data->nr_states)
97 		return -EINVAL;
98 
99 	return data->states[selector].value;
100 }
101 
102 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
103 					int min_uA, int max_uA)
104 {
105 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
106 	int ptr, target = 0, state, best_val = 0;
107 
108 	for (ptr = 0; ptr < data->nr_states; ptr++)
109 		if (data->states[ptr].value > best_val &&
110 		    data->states[ptr].value >= min_uA &&
111 		    data->states[ptr].value <= max_uA) {
112 			target = data->states[ptr].gpios;
113 			best_val = data->states[ptr].value;
114 		}
115 
116 	if (best_val == 0)
117 		return -EINVAL;
118 
119 	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
120 		state = (target & (1 << ptr)) >> ptr;
121 		gpiod_set_value_cansleep(data->gpiods[ptr], state);
122 	}
123 	data->state = target;
124 
125 	return 0;
126 }
127 
128 static struct regulator_ops gpio_regulator_voltage_ops = {
129 	.get_voltage = gpio_regulator_get_value,
130 	.set_voltage = gpio_regulator_set_voltage,
131 	.list_voltage = gpio_regulator_list_voltage,
132 };
133 
134 static struct gpio_regulator_config *
135 of_get_gpio_regulator_config(struct device *dev, struct device_node *np,
136 			     const struct regulator_desc *desc)
137 {
138 	struct gpio_regulator_config *config;
139 	const char *regtype;
140 	int proplen, i;
141 	int ngpios;
142 	int ret;
143 
144 	config = devm_kzalloc(dev,
145 			sizeof(struct gpio_regulator_config),
146 			GFP_KERNEL);
147 	if (!config)
148 		return ERR_PTR(-ENOMEM);
149 
150 	config->init_data = of_get_regulator_init_data(dev, np, desc);
151 	if (!config->init_data)
152 		return ERR_PTR(-EINVAL);
153 
154 	config->supply_name = config->init_data->constraints.name;
155 
156 	if (of_property_read_bool(np, "enable-at-boot"))
157 		config->enabled_at_boot = true;
158 
159 	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
160 
161 	/* Fetch GPIO init levels */
162 	ngpios = gpiod_count(dev, NULL);
163 	if (ngpios > 0) {
164 		config->gflags = devm_kzalloc(dev,
165 					      sizeof(enum gpiod_flags)
166 					      * ngpios,
167 					      GFP_KERNEL);
168 		if (!config->gflags)
169 			return ERR_PTR(-ENOMEM);
170 
171 		for (i = 0; i < ngpios; i++) {
172 			u32 val;
173 
174 			ret = of_property_read_u32_index(np, "gpios-states", i,
175 							 &val);
176 
177 			/* Default to high per specification */
178 			if (ret)
179 				config->gflags[i] = GPIOD_OUT_HIGH;
180 			else
181 				config->gflags[i] =
182 					val ? GPIOD_OUT_HIGH : GPIOD_OUT_LOW;
183 		}
184 	}
185 	config->ngpios = ngpios;
186 
187 	/* Fetch states. */
188 	proplen = of_property_count_u32_elems(np, "states");
189 	if (proplen < 0) {
190 		dev_err(dev, "No 'states' property found\n");
191 		return ERR_PTR(-EINVAL);
192 	}
193 
194 	config->states = devm_kcalloc(dev,
195 				proplen / 2,
196 				sizeof(struct gpio_regulator_state),
197 				GFP_KERNEL);
198 	if (!config->states)
199 		return ERR_PTR(-ENOMEM);
200 
201 	for (i = 0; i < proplen / 2; i++) {
202 		of_property_read_u32_index(np, "states", i * 2,
203 					   &config->states[i].value);
204 		of_property_read_u32_index(np, "states", i * 2 + 1,
205 					   &config->states[i].gpios);
206 	}
207 	config->nr_states = i;
208 
209 	config->type = REGULATOR_VOLTAGE;
210 	ret = of_property_read_string(np, "regulator-type", &regtype);
211 	if (ret >= 0) {
212 		if (!strncmp("voltage", regtype, 7))
213 			config->type = REGULATOR_VOLTAGE;
214 		else if (!strncmp("current", regtype, 7))
215 			config->type = REGULATOR_CURRENT;
216 		else
217 			dev_warn(dev, "Unknown regulator-type '%s'\n",
218 				 regtype);
219 	}
220 
221 	return config;
222 }
223 
224 static struct regulator_ops gpio_regulator_current_ops = {
225 	.get_current_limit = gpio_regulator_get_value,
226 	.set_current_limit = gpio_regulator_set_current_limit,
227 };
228 
229 static int gpio_regulator_probe(struct platform_device *pdev)
230 {
231 	struct device *dev = &pdev->dev;
232 	struct gpio_regulator_config *config = dev_get_platdata(dev);
233 	struct device_node *np = dev->of_node;
234 	struct gpio_regulator_data *drvdata;
235 	struct regulator_config cfg = { };
236 	enum gpiod_flags gflags;
237 	int ptr, ret, state, i;
238 
239 	drvdata = devm_kzalloc(dev, sizeof(struct gpio_regulator_data),
240 			       GFP_KERNEL);
241 	if (drvdata == NULL)
242 		return -ENOMEM;
243 
244 	if (np) {
245 		config = of_get_gpio_regulator_config(dev, np,
246 						      &drvdata->desc);
247 		if (IS_ERR(config))
248 			return PTR_ERR(config);
249 	}
250 
251 	drvdata->desc.name = devm_kstrdup(dev, config->supply_name, GFP_KERNEL);
252 	if (drvdata->desc.name == NULL) {
253 		dev_err(dev, "Failed to allocate supply name\n");
254 		return -ENOMEM;
255 	}
256 
257 	drvdata->gpiods = devm_kzalloc(dev, sizeof(struct gpio_desc *),
258 				       GFP_KERNEL);
259 	if (!drvdata->gpiods)
260 		return -ENOMEM;
261 	for (i = 0; i < config->ngpios; i++) {
262 		drvdata->gpiods[i] = devm_gpiod_get_index(dev,
263 							  NULL,
264 							  i,
265 							  config->gflags[i]);
266 		if (IS_ERR(drvdata->gpiods[i]))
267 			return PTR_ERR(drvdata->gpiods[i]);
268 		/* This is good to know */
269 		gpiod_set_consumer_name(drvdata->gpiods[i], drvdata->desc.name);
270 	}
271 	drvdata->nr_gpios = config->ngpios;
272 
273 	drvdata->states = devm_kmemdup(dev,
274 				       config->states,
275 				       config->nr_states *
276 				       sizeof(struct gpio_regulator_state),
277 				       GFP_KERNEL);
278 	if (drvdata->states == NULL) {
279 		dev_err(dev, "Failed to allocate state data\n");
280 		return -ENOMEM;
281 	}
282 	drvdata->nr_states = config->nr_states;
283 
284 	drvdata->desc.owner = THIS_MODULE;
285 	drvdata->desc.enable_time = config->startup_delay;
286 
287 	/* handle regulator type*/
288 	switch (config->type) {
289 	case REGULATOR_VOLTAGE:
290 		drvdata->desc.type = REGULATOR_VOLTAGE;
291 		drvdata->desc.ops = &gpio_regulator_voltage_ops;
292 		drvdata->desc.n_voltages = config->nr_states;
293 		break;
294 	case REGULATOR_CURRENT:
295 		drvdata->desc.type = REGULATOR_CURRENT;
296 		drvdata->desc.ops = &gpio_regulator_current_ops;
297 		break;
298 	default:
299 		dev_err(dev, "No regulator type set\n");
300 		return -EINVAL;
301 	}
302 
303 	/* build initial state from gpio init data. */
304 	state = 0;
305 	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
306 		if (config->gflags[ptr] == GPIOD_OUT_HIGH)
307 			state |= (1 << ptr);
308 	}
309 	drvdata->state = state;
310 
311 	cfg.dev = dev;
312 	cfg.init_data = config->init_data;
313 	cfg.driver_data = drvdata;
314 	cfg.of_node = np;
315 
316 	/*
317 	 * The signal will be inverted by the GPIO core if flagged so in the
318 	 * decriptor.
319 	 */
320 	if (config->enabled_at_boot)
321 		gflags = GPIOD_OUT_HIGH | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
322 	else
323 		gflags = GPIOD_OUT_LOW | GPIOD_FLAGS_BIT_NONEXCLUSIVE;
324 
325 	cfg.ena_gpiod = gpiod_get_optional(dev, "enable", gflags);
326 	if (IS_ERR(cfg.ena_gpiod))
327 		return PTR_ERR(cfg.ena_gpiod);
328 
329 	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
330 	if (IS_ERR(drvdata->dev)) {
331 		ret = PTR_ERR(drvdata->dev);
332 		dev_err(dev, "Failed to register regulator: %d\n", ret);
333 		return ret;
334 	}
335 
336 	platform_set_drvdata(pdev, drvdata);
337 
338 	return 0;
339 }
340 
341 static int gpio_regulator_remove(struct platform_device *pdev)
342 {
343 	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
344 
345 	regulator_unregister(drvdata->dev);
346 
347 	return 0;
348 }
349 
350 #if defined(CONFIG_OF)
351 static const struct of_device_id regulator_gpio_of_match[] = {
352 	{ .compatible = "regulator-gpio", },
353 	{},
354 };
355 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
356 #endif
357 
358 static struct platform_driver gpio_regulator_driver = {
359 	.probe		= gpio_regulator_probe,
360 	.remove		= gpio_regulator_remove,
361 	.driver		= {
362 		.name		= "gpio-regulator",
363 		.of_match_table = of_match_ptr(regulator_gpio_of_match),
364 	},
365 };
366 
367 static int __init gpio_regulator_init(void)
368 {
369 	return platform_driver_register(&gpio_regulator_driver);
370 }
371 subsys_initcall(gpio_regulator_init);
372 
373 static void __exit gpio_regulator_exit(void)
374 {
375 	platform_driver_unregister(&gpio_regulator_driver);
376 }
377 module_exit(gpio_regulator_exit);
378 
379 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
380 MODULE_DESCRIPTION("gpio voltage regulator");
381 MODULE_LICENSE("GPL");
382 MODULE_ALIAS("platform:gpio-regulator");
383