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 			     const struct regulator_desc *desc)
138 {
139 	struct gpio_regulator_config *config;
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, 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-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. - optional property*/
167 	ret = of_gpio_count(np);
168 	if ((ret < 0) && (ret != -ENOENT))
169 		return ERR_PTR(ret);
170 
171 	if (ret > 0) {
172 		config->nr_gpios = ret;
173 		config->gpios = devm_kzalloc(dev,
174 					sizeof(struct gpio) * config->nr_gpios,
175 					GFP_KERNEL);
176 		if (!config->gpios)
177 			return ERR_PTR(-ENOMEM);
178 
179 		proplen = of_property_count_u32_elems(np, "gpios-states");
180 		/* optional property */
181 		if (proplen < 0)
182 			proplen = 0;
183 
184 		if (proplen > 0 && proplen != config->nr_gpios) {
185 			dev_warn(dev, "gpios <-> gpios-states mismatch\n");
186 			proplen = 0;
187 		}
188 
189 		for (i = 0; i < config->nr_gpios; i++) {
190 			gpio = of_get_named_gpio(np, "gpios", i);
191 			if (gpio < 0)
192 				break;
193 			config->gpios[i].gpio = gpio;
194 			if (proplen > 0) {
195 				of_property_read_u32_index(np, "gpios-states",
196 							   i, &ret);
197 				if (ret)
198 					config->gpios[i].flags =
199 							   GPIOF_OUT_INIT_HIGH;
200 			}
201 		}
202 	}
203 
204 	/* Fetch states. */
205 	proplen = of_property_count_u32_elems(np, "states");
206 	if (proplen < 0) {
207 		dev_err(dev, "No 'states' property found\n");
208 		return ERR_PTR(-EINVAL);
209 	}
210 
211 	config->states = devm_kzalloc(dev,
212 				sizeof(struct gpio_regulator_state)
213 				* (proplen / 2),
214 				GFP_KERNEL);
215 	if (!config->states)
216 		return ERR_PTR(-ENOMEM);
217 
218 	for (i = 0; i < proplen / 2; i++) {
219 		of_property_read_u32_index(np, "states", i * 2,
220 					   &config->states[i].value);
221 		of_property_read_u32_index(np, "states", i * 2 + 1,
222 					   &config->states[i].gpios);
223 	}
224 	config->nr_states = i;
225 
226 	config->type = REGULATOR_VOLTAGE;
227 	ret = of_property_read_string(np, "regulator-type", &regtype);
228 	if (ret >= 0) {
229 		if (!strncmp("voltage", regtype, 7))
230 			config->type = REGULATOR_VOLTAGE;
231 		else if (!strncmp("current", regtype, 7))
232 			config->type = REGULATOR_CURRENT;
233 		else
234 			dev_warn(dev, "Unknown regulator-type '%s'\n",
235 				 regtype);
236 	}
237 
238 	return config;
239 }
240 
241 static struct regulator_ops gpio_regulator_current_ops = {
242 	.get_current_limit = gpio_regulator_get_value,
243 	.set_current_limit = gpio_regulator_set_current_limit,
244 };
245 
246 static int gpio_regulator_probe(struct platform_device *pdev)
247 {
248 	struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
249 	struct device_node *np = pdev->dev.of_node;
250 	struct gpio_regulator_data *drvdata;
251 	struct regulator_config cfg = { };
252 	int ptr, ret, state;
253 
254 	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
255 			       GFP_KERNEL);
256 	if (drvdata == NULL)
257 		return -ENOMEM;
258 
259 	if (np) {
260 		config = of_get_gpio_regulator_config(&pdev->dev, np,
261 						      &drvdata->desc);
262 		if (IS_ERR(config))
263 			return PTR_ERR(config);
264 	}
265 
266 	drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
267 	if (drvdata->desc.name == NULL) {
268 		dev_err(&pdev->dev, "Failed to allocate supply name\n");
269 		ret = -ENOMEM;
270 		goto err;
271 	}
272 
273 	if (config->nr_gpios != 0) {
274 		drvdata->gpios = kmemdup(config->gpios,
275 					 config->nr_gpios * sizeof(struct gpio),
276 					 GFP_KERNEL);
277 		if (drvdata->gpios == NULL) {
278 			dev_err(&pdev->dev, "Failed to allocate gpio data\n");
279 			ret = -ENOMEM;
280 			goto err_name;
281 		}
282 
283 		drvdata->nr_gpios = config->nr_gpios;
284 		ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
285 		if (ret) {
286 			if (ret != -EPROBE_DEFER)
287 				dev_err(&pdev->dev,
288 					"Could not obtain regulator setting GPIOs: %d\n",
289 					ret);
290 			goto err_memstate;
291 		}
292 	}
293 
294 	drvdata->states = kmemdup(config->states,
295 				  config->nr_states *
296 					 sizeof(struct gpio_regulator_state),
297 				  GFP_KERNEL);
298 	if (drvdata->states == NULL) {
299 		dev_err(&pdev->dev, "Failed to allocate state data\n");
300 		ret = -ENOMEM;
301 		goto err_memgpio;
302 	}
303 	drvdata->nr_states = config->nr_states;
304 
305 	drvdata->desc.owner = THIS_MODULE;
306 	drvdata->desc.enable_time = config->startup_delay;
307 
308 	/* handle regulator type*/
309 	switch (config->type) {
310 	case REGULATOR_VOLTAGE:
311 		drvdata->desc.type = REGULATOR_VOLTAGE;
312 		drvdata->desc.ops = &gpio_regulator_voltage_ops;
313 		drvdata->desc.n_voltages = config->nr_states;
314 		break;
315 	case REGULATOR_CURRENT:
316 		drvdata->desc.type = REGULATOR_CURRENT;
317 		drvdata->desc.ops = &gpio_regulator_current_ops;
318 		break;
319 	default:
320 		dev_err(&pdev->dev, "No regulator type set\n");
321 		ret = -EINVAL;
322 		goto err_memgpio;
323 	}
324 
325 	/* build initial state from gpio init data. */
326 	state = 0;
327 	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
328 		if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
329 			state |= (1 << ptr);
330 	}
331 	drvdata->state = state;
332 
333 	cfg.dev = &pdev->dev;
334 	cfg.init_data = config->init_data;
335 	cfg.driver_data = drvdata;
336 	cfg.of_node = np;
337 
338 	if (gpio_is_valid(config->enable_gpio)) {
339 		cfg.ena_gpio = config->enable_gpio;
340 		cfg.ena_gpio_initialized = true;
341 	}
342 	cfg.ena_gpio_invert = !config->enable_high;
343 	if (config->enabled_at_boot) {
344 		if (config->enable_high)
345 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
346 		else
347 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
348 	} else {
349 		if (config->enable_high)
350 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
351 		else
352 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
353 	}
354 
355 	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
356 	if (IS_ERR(drvdata->dev)) {
357 		ret = PTR_ERR(drvdata->dev);
358 		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
359 		goto err_stategpio;
360 	}
361 
362 	platform_set_drvdata(pdev, drvdata);
363 
364 	return 0;
365 
366 err_stategpio:
367 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
368 err_memstate:
369 	kfree(drvdata->states);
370 err_memgpio:
371 	kfree(drvdata->gpios);
372 err_name:
373 	kfree(drvdata->desc.name);
374 err:
375 	return ret;
376 }
377 
378 static int gpio_regulator_remove(struct platform_device *pdev)
379 {
380 	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
381 
382 	regulator_unregister(drvdata->dev);
383 
384 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
385 
386 	kfree(drvdata->states);
387 	kfree(drvdata->gpios);
388 
389 	kfree(drvdata->desc.name);
390 
391 	return 0;
392 }
393 
394 #if defined(CONFIG_OF)
395 static const struct of_device_id regulator_gpio_of_match[] = {
396 	{ .compatible = "regulator-gpio", },
397 	{},
398 };
399 MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
400 #endif
401 
402 static struct platform_driver gpio_regulator_driver = {
403 	.probe		= gpio_regulator_probe,
404 	.remove		= gpio_regulator_remove,
405 	.driver		= {
406 		.name		= "gpio-regulator",
407 		.of_match_table = of_match_ptr(regulator_gpio_of_match),
408 	},
409 };
410 
411 static int __init gpio_regulator_init(void)
412 {
413 	return platform_driver_register(&gpio_regulator_driver);
414 }
415 subsys_initcall(gpio_regulator_init);
416 
417 static void __exit gpio_regulator_exit(void)
418 {
419 	platform_driver_unregister(&gpio_regulator_driver);
420 }
421 module_exit(gpio_regulator_exit);
422 
423 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
424 MODULE_DESCRIPTION("gpio voltage regulator");
425 MODULE_LICENSE("GPL");
426 MODULE_ALIAS("platform:gpio-regulator");
427