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 	const char *regtype;
140 	int proplen, gpio, i;
141 	int ret;
142 
143 	config = devm_kzalloc(dev,
144 			sizeof(struct gpio_regulator_config),
145 			GFP_KERNEL);
146 	if (!config)
147 		return ERR_PTR(-ENOMEM);
148 
149 	config->init_data = of_get_regulator_init_data(dev, np);
150 	if (!config->init_data)
151 		return ERR_PTR(-EINVAL);
152 
153 	config->supply_name = config->init_data->constraints.name;
154 
155 	if (of_property_read_bool(np, "enable-active-high"))
156 		config->enable_high = true;
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 	config->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
164 
165 	/* Fetch GPIOs. */
166 	config->nr_gpios = of_gpio_count(np);
167 
168 	config->gpios = devm_kzalloc(dev,
169 				sizeof(struct gpio) * config->nr_gpios,
170 				GFP_KERNEL);
171 	if (!config->gpios)
172 		return ERR_PTR(-ENOMEM);
173 
174 	proplen = of_property_count_u32_elems(np, "gpios-states");
175 	/* optional property */
176 	if (proplen < 0)
177 		proplen = 0;
178 
179 	if (proplen > 0 && proplen != config->nr_gpios) {
180 		dev_warn(dev, "gpios <-> gpios-states mismatch\n");
181 		proplen = 0;
182 	}
183 
184 	for (i = 0; i < config->nr_gpios; i++) {
185 		gpio = of_get_named_gpio(np, "gpios", i);
186 		if (gpio < 0)
187 			break;
188 		config->gpios[i].gpio = gpio;
189 		if (proplen > 0) {
190 			of_property_read_u32_index(np, "gpios-states", i, &ret);
191 			if (ret)
192 				config->gpios[i].flags = GPIOF_OUT_INIT_HIGH;
193 		}
194 	}
195 
196 	/* Fetch states. */
197 	proplen = of_property_count_u32_elems(np, "states");
198 	if (proplen < 0) {
199 		dev_err(dev, "No 'states' property found\n");
200 		return ERR_PTR(-EINVAL);
201 	}
202 
203 	config->states = devm_kzalloc(dev,
204 				sizeof(struct gpio_regulator_state)
205 				* (proplen / 2),
206 				GFP_KERNEL);
207 	if (!config->states)
208 		return ERR_PTR(-ENOMEM);
209 
210 	for (i = 0; i < proplen / 2; i++) {
211 		of_property_read_u32_index(np, "states", i * 2,
212 					   &config->states[i].value);
213 		of_property_read_u32_index(np, "states", i * 2 + 1,
214 					   &config->states[i].gpios);
215 	}
216 	config->nr_states = i;
217 
218 	config->type = REGULATOR_VOLTAGE;
219 	ret = of_property_read_string(np, "regulator-type", &regtype);
220 	if (ret >= 0) {
221 		if (!strncmp("voltage", regtype, 7))
222 			config->type = REGULATOR_VOLTAGE;
223 		else if (!strncmp("current", regtype, 7))
224 			config->type = REGULATOR_CURRENT;
225 		else
226 			dev_warn(dev, "Unknown regulator-type '%s'\n",
227 				 regtype);
228 	}
229 
230 	return config;
231 }
232 
233 static struct regulator_ops gpio_regulator_current_ops = {
234 	.get_current_limit = gpio_regulator_get_value,
235 	.set_current_limit = gpio_regulator_set_current_limit,
236 };
237 
238 static int gpio_regulator_probe(struct platform_device *pdev)
239 {
240 	struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
241 	struct device_node *np = pdev->dev.of_node;
242 	struct gpio_regulator_data *drvdata;
243 	struct regulator_config cfg = { };
244 	int ptr, ret, state;
245 
246 	if (np) {
247 		config = of_get_gpio_regulator_config(&pdev->dev, np);
248 		if (IS_ERR(config))
249 			return PTR_ERR(config);
250 	}
251 
252 	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
253 			       GFP_KERNEL);
254 	if (drvdata == NULL)
255 		return -ENOMEM;
256 
257 	drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
258 	if (drvdata->desc.name == NULL) {
259 		dev_err(&pdev->dev, "Failed to allocate supply name\n");
260 		ret = -ENOMEM;
261 		goto err;
262 	}
263 
264 	drvdata->gpios = kmemdup(config->gpios,
265 				 config->nr_gpios * sizeof(struct gpio),
266 				 GFP_KERNEL);
267 	if (drvdata->gpios == NULL) {
268 		dev_err(&pdev->dev, "Failed to allocate gpio data\n");
269 		ret = -ENOMEM;
270 		goto err_name;
271 	}
272 
273 	drvdata->states = kmemdup(config->states,
274 				  config->nr_states *
275 					 sizeof(struct gpio_regulator_state),
276 				  GFP_KERNEL);
277 	if (drvdata->states == NULL) {
278 		dev_err(&pdev->dev, "Failed to allocate state data\n");
279 		ret = -ENOMEM;
280 		goto err_memgpio;
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(&pdev->dev, "No regulator type set\n");
300 		ret = -EINVAL;
301 		goto err_memgpio;
302 	}
303 
304 	drvdata->nr_gpios = config->nr_gpios;
305 	ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
306 	if (ret) {
307 		dev_err(&pdev->dev,
308 		   "Could not obtain regulator setting GPIOs: %d\n", ret);
309 		goto err_memstate;
310 	}
311 
312 	/* build initial state from gpio init data. */
313 	state = 0;
314 	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
315 		if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
316 			state |= (1 << ptr);
317 	}
318 	drvdata->state = state;
319 
320 	cfg.dev = &pdev->dev;
321 	cfg.init_data = config->init_data;
322 	cfg.driver_data = drvdata;
323 	cfg.of_node = np;
324 
325 	if (config->enable_gpio >= 0)
326 		cfg.ena_gpio = config->enable_gpio;
327 	cfg.ena_gpio_invert = !config->enable_high;
328 	if (config->enabled_at_boot) {
329 		if (config->enable_high)
330 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
331 		else
332 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
333 	} else {
334 		if (config->enable_high)
335 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
336 		else
337 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
338 	}
339 
340 	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
341 	if (IS_ERR(drvdata->dev)) {
342 		ret = PTR_ERR(drvdata->dev);
343 		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
344 		goto err_stategpio;
345 	}
346 
347 	platform_set_drvdata(pdev, drvdata);
348 
349 	return 0;
350 
351 err_stategpio:
352 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
353 err_memstate:
354 	kfree(drvdata->states);
355 err_memgpio:
356 	kfree(drvdata->gpios);
357 err_name:
358 	kfree(drvdata->desc.name);
359 err:
360 	return ret;
361 }
362 
363 static int gpio_regulator_remove(struct platform_device *pdev)
364 {
365 	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
366 
367 	regulator_unregister(drvdata->dev);
368 
369 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
370 
371 	kfree(drvdata->states);
372 	kfree(drvdata->gpios);
373 
374 	kfree(drvdata->desc.name);
375 
376 	return 0;
377 }
378 
379 #if defined(CONFIG_OF)
380 static const struct of_device_id regulator_gpio_of_match[] = {
381 	{ .compatible = "regulator-gpio", },
382 	{},
383 };
384 #endif
385 
386 static struct platform_driver gpio_regulator_driver = {
387 	.probe		= gpio_regulator_probe,
388 	.remove		= gpio_regulator_remove,
389 	.driver		= {
390 		.name		= "gpio-regulator",
391 		.owner		= THIS_MODULE,
392 		.of_match_table = of_match_ptr(regulator_gpio_of_match),
393 	},
394 };
395 
396 static int __init gpio_regulator_init(void)
397 {
398 	return platform_driver_register(&gpio_regulator_driver);
399 }
400 subsys_initcall(gpio_regulator_init);
401 
402 static void __exit gpio_regulator_exit(void)
403 {
404 	platform_driver_unregister(&gpio_regulator_driver);
405 }
406 module_exit(gpio_regulator_exit);
407 
408 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
409 MODULE_DESCRIPTION("gpio voltage regulator");
410 MODULE_LICENSE("GPL");
411 MODULE_ALIAS("platform:gpio-regulator");
412