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{
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
233static 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
238static 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
351err_stategpio:
352	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
353err_memstate:
354	kfree(drvdata->states);
355err_memgpio:
356	kfree(drvdata->gpios);
357err_name:
358	kfree(drvdata->desc.name);
359err:
360	return ret;
361}
362
363static 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)
380static const struct of_device_id regulator_gpio_of_match[] = {
381	{ .compatible = "regulator-gpio", },
382	{},
383};
384#endif
385
386static 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
396static int __init gpio_regulator_init(void)
397{
398	return platform_driver_register(&gpio_regulator_driver);
399}
400subsys_initcall(gpio_regulator_init);
401
402static void __exit gpio_regulator_exit(void)
403{
404	platform_driver_unregister(&gpio_regulator_driver);
405}
406module_exit(gpio_regulator_exit);
407
408MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
409MODULE_DESCRIPTION("gpio voltage regulator");
410MODULE_LICENSE("GPL");
411MODULE_ALIAS("platform:gpio-regulator");
412