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.h>
34 #include <linux/slab.h>
35 #include <linux/of.h>
36 #include <linux/of_gpio.h>
37 
38 struct gpio_regulator_data {
39 	struct regulator_desc desc;
40 	struct regulator_dev *dev;
41 
42 	struct gpio *gpios;
43 	int nr_gpios;
44 
45 	struct gpio_regulator_state *states;
46 	int nr_states;
47 
48 	int state;
49 };
50 
51 static int gpio_regulator_get_value(struct regulator_dev *dev)
52 {
53 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
54 	int ptr;
55 
56 	for (ptr = 0; ptr < data->nr_states; ptr++)
57 		if (data->states[ptr].gpios == data->state)
58 			return data->states[ptr].value;
59 
60 	return -EINVAL;
61 }
62 
63 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
64 					int min_uV, int max_uV,
65 					unsigned *selector)
66 {
67 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
68 	int ptr, target = 0, state, best_val = INT_MAX;
69 
70 	for (ptr = 0; ptr < data->nr_states; ptr++)
71 		if (data->states[ptr].value < best_val &&
72 		    data->states[ptr].value >= min_uV &&
73 		    data->states[ptr].value <= max_uV) {
74 			target = data->states[ptr].gpios;
75 			best_val = data->states[ptr].value;
76 			if (selector)
77 				*selector = ptr;
78 		}
79 
80 	if (best_val == INT_MAX)
81 		return -EINVAL;
82 
83 	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
84 		state = (target & (1 << ptr)) >> ptr;
85 		gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
86 	}
87 	data->state = target;
88 
89 	return 0;
90 }
91 
92 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
93 				      unsigned selector)
94 {
95 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
96 
97 	if (selector >= data->nr_states)
98 		return -EINVAL;
99 
100 	return data->states[selector].value;
101 }
102 
103 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
104 					int min_uA, int max_uA)
105 {
106 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
107 	int ptr, target = 0, state, best_val = 0;
108 
109 	for (ptr = 0; ptr < data->nr_states; ptr++)
110 		if (data->states[ptr].value > best_val &&
111 		    data->states[ptr].value >= min_uA &&
112 		    data->states[ptr].value <= max_uA) {
113 			target = data->states[ptr].gpios;
114 			best_val = data->states[ptr].value;
115 		}
116 
117 	if (best_val == 0)
118 		return -EINVAL;
119 
120 	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
121 		state = (target & (1 << ptr)) >> ptr;
122 		gpio_set_value_cansleep(data->gpios[ptr].gpio, state);
123 	}
124 	data->state = target;
125 
126 	return 0;
127 }
128 
129 static struct regulator_ops gpio_regulator_voltage_ops = {
130 	.get_voltage = gpio_regulator_get_value,
131 	.set_voltage = gpio_regulator_set_voltage,
132 	.list_voltage = gpio_regulator_list_voltage,
133 };
134 
135 static struct gpio_regulator_config *
136 of_get_gpio_regulator_config(struct device *dev, struct device_node *np)
137 {
138 	struct gpio_regulator_config *config;
139 	struct property *prop;
140 	const char *regtype;
141 	int proplen, gpio, i;
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);
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-active-high"))
157 		config->enable_high = true;
158 
159 	if (of_property_read_bool(np, "enable-at-boot"))
160 		config->enabled_at_boot = true;
161 
162 	of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
163 
164 	config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
165 
166 	/* Fetch GPIOs. */
167 	config->nr_gpios = of_gpio_count(np);
168 
169 	config->gpios = devm_kzalloc(dev,
170 				sizeof(struct gpio) * config->nr_gpios,
171 				GFP_KERNEL);
172 	if (!config->gpios)
173 		return ERR_PTR(-ENOMEM);
174 
175 	for (i = 0; i < config->nr_gpios; i++) {
176 		gpio = of_get_named_gpio(np, "gpios", i);
177 		if (gpio < 0)
178 			break;
179 		config->gpios[i].gpio = gpio;
180 	}
181 
182 	/* Fetch states. */
183 	prop = of_find_property(np, "states", NULL);
184 	if (!prop) {
185 		dev_err(dev, "No 'states' property found\n");
186 		return ERR_PTR(-EINVAL);
187 	}
188 
189 	proplen = prop->length / sizeof(int);
190 
191 	config->states = devm_kzalloc(dev,
192 				sizeof(struct gpio_regulator_state)
193 				* (proplen / 2),
194 				GFP_KERNEL);
195 	if (!config->states)
196 		return ERR_PTR(-ENOMEM);
197 
198 	for (i = 0; i < proplen / 2; i++) {
199 		config->states[i].value =
200 			be32_to_cpup((int *)prop->value + (i * 2));
201 		config->states[i].gpios =
202 			be32_to_cpup((int *)prop->value + (i * 2 + 1));
203 	}
204 	config->nr_states = i;
205 
206 	config->type = REGULATOR_VOLTAGE;
207 	ret = of_property_read_string(np, "regulator-type", &regtype);
208 	if (ret >= 0) {
209 		if (!strncmp("voltage", regtype, 7))
210 			config->type = REGULATOR_VOLTAGE;
211 		else if (!strncmp("current", regtype, 7))
212 			config->type = REGULATOR_CURRENT;
213 		else
214 			dev_warn(dev, "Unknown regulator-type '%s'\n",
215 				 regtype);
216 	}
217 
218 	return config;
219 }
220 
221 static struct regulator_ops gpio_regulator_current_ops = {
222 	.get_current_limit = gpio_regulator_get_value,
223 	.set_current_limit = gpio_regulator_set_current_limit,
224 };
225 
226 static int gpio_regulator_probe(struct platform_device *pdev)
227 {
228 	struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
229 	struct device_node *np = pdev->dev.of_node;
230 	struct gpio_regulator_data *drvdata;
231 	struct regulator_config cfg = { };
232 	int ptr, ret, state;
233 
234 	if (np) {
235 		config = of_get_gpio_regulator_config(&pdev->dev, np);
236 		if (IS_ERR(config))
237 			return PTR_ERR(config);
238 	}
239 
240 	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
241 			       GFP_KERNEL);
242 	if (drvdata == NULL) {
243 		dev_err(&pdev->dev, "Failed to allocate device data\n");
244 		return -ENOMEM;
245 	}
246 
247 	drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
248 	if (drvdata->desc.name == NULL) {
249 		dev_err(&pdev->dev, "Failed to allocate supply name\n");
250 		ret = -ENOMEM;
251 		goto err;
252 	}
253 
254 	drvdata->gpios = kmemdup(config->gpios,
255 				 config->nr_gpios * sizeof(struct gpio),
256 				 GFP_KERNEL);
257 	if (drvdata->gpios == NULL) {
258 		dev_err(&pdev->dev, "Failed to allocate gpio data\n");
259 		ret = -ENOMEM;
260 		goto err_name;
261 	}
262 
263 	drvdata->states = kmemdup(config->states,
264 				  config->nr_states *
265 					 sizeof(struct gpio_regulator_state),
266 				  GFP_KERNEL);
267 	if (drvdata->states == NULL) {
268 		dev_err(&pdev->dev, "Failed to allocate state data\n");
269 		ret = -ENOMEM;
270 		goto err_memgpio;
271 	}
272 	drvdata->nr_states = config->nr_states;
273 
274 	drvdata->desc.owner = THIS_MODULE;
275 	drvdata->desc.enable_time = config->startup_delay;
276 
277 	/* handle regulator type*/
278 	switch (config->type) {
279 	case REGULATOR_VOLTAGE:
280 		drvdata->desc.type = REGULATOR_VOLTAGE;
281 		drvdata->desc.ops = &gpio_regulator_voltage_ops;
282 		drvdata->desc.n_voltages = config->nr_states;
283 		break;
284 	case REGULATOR_CURRENT:
285 		drvdata->desc.type = REGULATOR_CURRENT;
286 		drvdata->desc.ops = &gpio_regulator_current_ops;
287 		break;
288 	default:
289 		dev_err(&pdev->dev, "No regulator type set\n");
290 		ret = -EINVAL;
291 		goto err_memgpio;
292 	}
293 
294 	drvdata->nr_gpios = config->nr_gpios;
295 	ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
296 	if (ret) {
297 		dev_err(&pdev->dev,
298 		   "Could not obtain regulator setting GPIOs: %d\n", ret);
299 		goto err_memstate;
300 	}
301 
302 	/* build initial state from gpio init data. */
303 	state = 0;
304 	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
305 		if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
306 			state |= (1 << ptr);
307 	}
308 	drvdata->state = state;
309 
310 	cfg.dev = &pdev->dev;
311 	cfg.init_data = config->init_data;
312 	cfg.driver_data = drvdata;
313 	cfg.of_node = np;
314 
315 	if (config->enable_gpio >= 0)
316 		cfg.ena_gpio = config->enable_gpio;
317 	cfg.ena_gpio_invert = !config->enable_high;
318 	if (config->enabled_at_boot) {
319 		if (config->enable_high)
320 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
321 		else
322 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
323 	} else {
324 		if (config->enable_high)
325 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
326 		else
327 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
328 	}
329 
330 	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
331 	if (IS_ERR(drvdata->dev)) {
332 		ret = PTR_ERR(drvdata->dev);
333 		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
334 		goto err_stategpio;
335 	}
336 
337 	platform_set_drvdata(pdev, drvdata);
338 
339 	return 0;
340 
341 err_stategpio:
342 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
343 err_memstate:
344 	kfree(drvdata->states);
345 err_memgpio:
346 	kfree(drvdata->gpios);
347 err_name:
348 	kfree(drvdata->desc.name);
349 err:
350 	return ret;
351 }
352 
353 static int gpio_regulator_remove(struct platform_device *pdev)
354 {
355 	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
356 
357 	regulator_unregister(drvdata->dev);
358 
359 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
360 
361 	kfree(drvdata->states);
362 	kfree(drvdata->gpios);
363 
364 	kfree(drvdata->desc.name);
365 
366 	return 0;
367 }
368 
369 #if defined(CONFIG_OF)
370 static const struct of_device_id regulator_gpio_of_match[] = {
371 	{ .compatible = "regulator-gpio", },
372 	{},
373 };
374 #endif
375 
376 static struct platform_driver gpio_regulator_driver = {
377 	.probe		= gpio_regulator_probe,
378 	.remove		= gpio_regulator_remove,
379 	.driver		= {
380 		.name		= "gpio-regulator",
381 		.owner		= THIS_MODULE,
382 		.of_match_table = of_match_ptr(regulator_gpio_of_match),
383 	},
384 };
385 
386 static int __init gpio_regulator_init(void)
387 {
388 	return platform_driver_register(&gpio_regulator_driver);
389 }
390 subsys_initcall(gpio_regulator_init);
391 
392 static void __exit gpio_regulator_exit(void)
393 {
394 	platform_driver_unregister(&gpio_regulator_driver);
395 }
396 module_exit(gpio_regulator_exit);
397 
398 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
399 MODULE_DESCRIPTION("gpio voltage regulator");
400 MODULE_LICENSE("GPL");
401 MODULE_ALIAS("platform:gpio-regulator");
402