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	if (config->enable_gpio < 0 && config->enable_gpio != -ENOENT)
166		return ERR_PTR(config->enable_gpio);
167
168	/* Fetch GPIOs. - optional property*/
169	ret = of_gpio_count(np);
170	if ((ret < 0) && (ret != -ENOENT))
171		return ERR_PTR(ret);
172
173	if (ret > 0) {
174		config->nr_gpios = ret;
175		config->gpios = devm_kzalloc(dev,
176					sizeof(struct gpio) * config->nr_gpios,
177					GFP_KERNEL);
178		if (!config->gpios)
179			return ERR_PTR(-ENOMEM);
180
181		proplen = of_property_count_u32_elems(np, "gpios-states");
182		/* optional property */
183		if (proplen < 0)
184			proplen = 0;
185
186		if (proplen > 0 && proplen != config->nr_gpios) {
187			dev_warn(dev, "gpios <-> gpios-states mismatch\n");
188			proplen = 0;
189		}
190
191		for (i = 0; i < config->nr_gpios; i++) {
192			gpio = of_get_named_gpio(np, "gpios", i);
193			if (gpio < 0) {
194				if (gpio != -ENOENT)
195					return ERR_PTR(gpio);
196				break;
197			}
198			config->gpios[i].gpio = gpio;
199			if (proplen > 0) {
200				of_property_read_u32_index(np, "gpios-states",
201							   i, &ret);
202				if (ret)
203					config->gpios[i].flags =
204							   GPIOF_OUT_INIT_HIGH;
205			}
206		}
207	}
208
209	/* Fetch states. */
210	proplen = of_property_count_u32_elems(np, "states");
211	if (proplen < 0) {
212		dev_err(dev, "No 'states' property found\n");
213		return ERR_PTR(-EINVAL);
214	}
215
216	config->states = devm_kzalloc(dev,
217				sizeof(struct gpio_regulator_state)
218				* (proplen / 2),
219				GFP_KERNEL);
220	if (!config->states)
221		return ERR_PTR(-ENOMEM);
222
223	for (i = 0; i < proplen / 2; i++) {
224		of_property_read_u32_index(np, "states", i * 2,
225					   &config->states[i].value);
226		of_property_read_u32_index(np, "states", i * 2 + 1,
227					   &config->states[i].gpios);
228	}
229	config->nr_states = i;
230
231	config->type = REGULATOR_VOLTAGE;
232	ret = of_property_read_string(np, "regulator-type", &regtype);
233	if (ret >= 0) {
234		if (!strncmp("voltage", regtype, 7))
235			config->type = REGULATOR_VOLTAGE;
236		else if (!strncmp("current", regtype, 7))
237			config->type = REGULATOR_CURRENT;
238		else
239			dev_warn(dev, "Unknown regulator-type '%s'\n",
240				 regtype);
241	}
242
243	return config;
244}
245
246static struct regulator_ops gpio_regulator_current_ops = {
247	.get_current_limit = gpio_regulator_get_value,
248	.set_current_limit = gpio_regulator_set_current_limit,
249};
250
251static int gpio_regulator_probe(struct platform_device *pdev)
252{
253	struct gpio_regulator_config *config = dev_get_platdata(&pdev->dev);
254	struct device_node *np = pdev->dev.of_node;
255	struct gpio_regulator_data *drvdata;
256	struct regulator_config cfg = { };
257	int ptr, ret, state;
258
259	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
260			       GFP_KERNEL);
261	if (drvdata == NULL)
262		return -ENOMEM;
263
264	if (np) {
265		config = of_get_gpio_regulator_config(&pdev->dev, np,
266						      &drvdata->desc);
267		if (IS_ERR(config))
268			return PTR_ERR(config);
269	}
270
271	drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
272	if (drvdata->desc.name == NULL) {
273		dev_err(&pdev->dev, "Failed to allocate supply name\n");
274		ret = -ENOMEM;
275		goto err;
276	}
277
278	if (config->nr_gpios != 0) {
279		drvdata->gpios = kmemdup(config->gpios,
280					 config->nr_gpios * sizeof(struct gpio),
281					 GFP_KERNEL);
282		if (drvdata->gpios == NULL) {
283			dev_err(&pdev->dev, "Failed to allocate gpio data\n");
284			ret = -ENOMEM;
285			goto err_name;
286		}
287
288		drvdata->nr_gpios = config->nr_gpios;
289		ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
290		if (ret) {
291			if (ret != -EPROBE_DEFER)
292				dev_err(&pdev->dev,
293					"Could not obtain regulator setting GPIOs: %d\n",
294					ret);
295			goto err_memstate;
296		}
297	}
298
299	drvdata->states = kmemdup(config->states,
300				  config->nr_states *
301					 sizeof(struct gpio_regulator_state),
302				  GFP_KERNEL);
303	if (drvdata->states == NULL) {
304		dev_err(&pdev->dev, "Failed to allocate state data\n");
305		ret = -ENOMEM;
306		goto err_memgpio;
307	}
308	drvdata->nr_states = config->nr_states;
309
310	drvdata->desc.owner = THIS_MODULE;
311	drvdata->desc.enable_time = config->startup_delay;
312
313	/* handle regulator type*/
314	switch (config->type) {
315	case REGULATOR_VOLTAGE:
316		drvdata->desc.type = REGULATOR_VOLTAGE;
317		drvdata->desc.ops = &gpio_regulator_voltage_ops;
318		drvdata->desc.n_voltages = config->nr_states;
319		break;
320	case REGULATOR_CURRENT:
321		drvdata->desc.type = REGULATOR_CURRENT;
322		drvdata->desc.ops = &gpio_regulator_current_ops;
323		break;
324	default:
325		dev_err(&pdev->dev, "No regulator type set\n");
326		ret = -EINVAL;
327		goto err_memgpio;
328	}
329
330	/* build initial state from gpio init data. */
331	state = 0;
332	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
333		if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
334			state |= (1 << ptr);
335	}
336	drvdata->state = state;
337
338	cfg.dev = &pdev->dev;
339	cfg.init_data = config->init_data;
340	cfg.driver_data = drvdata;
341	cfg.of_node = np;
342
343	if (gpio_is_valid(config->enable_gpio)) {
344		cfg.ena_gpio = config->enable_gpio;
345		cfg.ena_gpio_initialized = true;
346	}
347	cfg.ena_gpio_invert = !config->enable_high;
348	if (config->enabled_at_boot) {
349		if (config->enable_high)
350			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
351		else
352			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
353	} else {
354		if (config->enable_high)
355			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
356		else
357			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
358	}
359
360	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
361	if (IS_ERR(drvdata->dev)) {
362		ret = PTR_ERR(drvdata->dev);
363		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
364		goto err_stategpio;
365	}
366
367	platform_set_drvdata(pdev, drvdata);
368
369	return 0;
370
371err_stategpio:
372	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
373err_memstate:
374	kfree(drvdata->states);
375err_memgpio:
376	kfree(drvdata->gpios);
377err_name:
378	kfree(drvdata->desc.name);
379err:
380	return ret;
381}
382
383static int gpio_regulator_remove(struct platform_device *pdev)
384{
385	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
386
387	regulator_unregister(drvdata->dev);
388
389	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
390
391	kfree(drvdata->states);
392	kfree(drvdata->gpios);
393
394	kfree(drvdata->desc.name);
395
396	return 0;
397}
398
399#if defined(CONFIG_OF)
400static const struct of_device_id regulator_gpio_of_match[] = {
401	{ .compatible = "regulator-gpio", },
402	{},
403};
404MODULE_DEVICE_TABLE(of, regulator_gpio_of_match);
405#endif
406
407static struct platform_driver gpio_regulator_driver = {
408	.probe		= gpio_regulator_probe,
409	.remove		= gpio_regulator_remove,
410	.driver		= {
411		.name		= "gpio-regulator",
412		.of_match_table = of_match_ptr(regulator_gpio_of_match),
413	},
414};
415
416static int __init gpio_regulator_init(void)
417{
418	return platform_driver_register(&gpio_regulator_driver);
419}
420subsys_initcall(gpio_regulator_init);
421
422static void __exit gpio_regulator_exit(void)
423{
424	platform_driver_unregister(&gpio_regulator_driver);
425}
426module_exit(gpio_regulator_exit);
427
428MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
429MODULE_DESCRIPTION("gpio voltage regulator");
430MODULE_LICENSE("GPL");
431MODULE_ALIAS("platform:gpio-regulator");