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
38struct 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
51static 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
63static 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
92static 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
103static 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
129static 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
135static struct gpio_regulator_config *
136of_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
241static 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
246static 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			dev_err(&pdev->dev,
287			"Could not obtain regulator setting GPIOs: %d\n", ret);
288			goto err_memstate;
289		}
290	}
291
292	drvdata->states = kmemdup(config->states,
293				  config->nr_states *
294					 sizeof(struct gpio_regulator_state),
295				  GFP_KERNEL);
296	if (drvdata->states == NULL) {
297		dev_err(&pdev->dev, "Failed to allocate state data\n");
298		ret = -ENOMEM;
299		goto err_memgpio;
300	}
301	drvdata->nr_states = config->nr_states;
302
303	drvdata->desc.owner = THIS_MODULE;
304	drvdata->desc.enable_time = config->startup_delay;
305
306	/* handle regulator type*/
307	switch (config->type) {
308	case REGULATOR_VOLTAGE:
309		drvdata->desc.type = REGULATOR_VOLTAGE;
310		drvdata->desc.ops = &gpio_regulator_voltage_ops;
311		drvdata->desc.n_voltages = config->nr_states;
312		break;
313	case REGULATOR_CURRENT:
314		drvdata->desc.type = REGULATOR_CURRENT;
315		drvdata->desc.ops = &gpio_regulator_current_ops;
316		break;
317	default:
318		dev_err(&pdev->dev, "No regulator type set\n");
319		ret = -EINVAL;
320		goto err_memgpio;
321	}
322
323	/* build initial state from gpio init data. */
324	state = 0;
325	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
326		if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
327			state |= (1 << ptr);
328	}
329	drvdata->state = state;
330
331	cfg.dev = &pdev->dev;
332	cfg.init_data = config->init_data;
333	cfg.driver_data = drvdata;
334	cfg.of_node = np;
335
336	if (gpio_is_valid(config->enable_gpio)) {
337		cfg.ena_gpio = config->enable_gpio;
338		cfg.ena_gpio_initialized = true;
339	}
340	cfg.ena_gpio_invert = !config->enable_high;
341	if (config->enabled_at_boot) {
342		if (config->enable_high)
343			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
344		else
345			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
346	} else {
347		if (config->enable_high)
348			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
349		else
350			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
351	}
352
353	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
354	if (IS_ERR(drvdata->dev)) {
355		ret = PTR_ERR(drvdata->dev);
356		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
357		goto err_stategpio;
358	}
359
360	platform_set_drvdata(pdev, drvdata);
361
362	return 0;
363
364err_stategpio:
365	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
366err_memstate:
367	kfree(drvdata->states);
368err_memgpio:
369	kfree(drvdata->gpios);
370err_name:
371	kfree(drvdata->desc.name);
372err:
373	return ret;
374}
375
376static int gpio_regulator_remove(struct platform_device *pdev)
377{
378	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
379
380	regulator_unregister(drvdata->dev);
381
382	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
383
384	kfree(drvdata->states);
385	kfree(drvdata->gpios);
386
387	kfree(drvdata->desc.name);
388
389	return 0;
390}
391
392#if defined(CONFIG_OF)
393static const struct of_device_id regulator_gpio_of_match[] = {
394	{ .compatible = "regulator-gpio", },
395	{},
396};
397#endif
398
399static struct platform_driver gpio_regulator_driver = {
400	.probe		= gpio_regulator_probe,
401	.remove		= gpio_regulator_remove,
402	.driver		= {
403		.name		= "gpio-regulator",
404		.of_match_table = of_match_ptr(regulator_gpio_of_match),
405	},
406};
407
408static int __init gpio_regulator_init(void)
409{
410	return platform_driver_register(&gpio_regulator_driver);
411}
412subsys_initcall(gpio_regulator_init);
413
414static void __exit gpio_regulator_exit(void)
415{
416	platform_driver_unregister(&gpio_regulator_driver);
417}
418module_exit(gpio_regulator_exit);
419
420MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
421MODULE_DESCRIPTION("gpio voltage regulator");
422MODULE_LICENSE("GPL");
423MODULE_ALIAS("platform:gpio-regulator");
424