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/gpio-regulator.h>
 32#include <linux/gpio.h>
 33#include <linux/slab.h>
 34
 35struct gpio_regulator_data {
 36	struct regulator_desc desc;
 37	struct regulator_dev *dev;
 38
 39	int enable_gpio;
 40	bool enable_high;
 41	bool is_enabled;
 42	unsigned startup_delay;
 43
 44	struct gpio *gpios;
 45	int nr_gpios;
 46
 47	struct gpio_regulator_state *states;
 48	int nr_states;
 49
 50	int state;
 51};
 52
 53static int gpio_regulator_is_enabled(struct regulator_dev *dev)
 54{
 55	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 56
 57	return data->is_enabled;
 58}
 59
 60static int gpio_regulator_enable(struct regulator_dev *dev)
 61{
 62	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 63
 64	if (gpio_is_valid(data->enable_gpio)) {
 65		gpio_set_value_cansleep(data->enable_gpio, data->enable_high);
 66		data->is_enabled = true;
 67	}
 68
 69	return 0;
 70}
 71
 72static int gpio_regulator_disable(struct regulator_dev *dev)
 73{
 74	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 75
 76	if (gpio_is_valid(data->enable_gpio)) {
 77		gpio_set_value_cansleep(data->enable_gpio, !data->enable_high);
 78		data->is_enabled = false;
 79	}
 80
 81	return 0;
 82}
 83
 84static int gpio_regulator_enable_time(struct regulator_dev *dev)
 85{
 86	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 87
 88	return data->startup_delay;
 89}
 90
 91static int gpio_regulator_get_value(struct regulator_dev *dev)
 92{
 93	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
 94	int ptr;
 95
 96	for (ptr = 0; ptr < data->nr_states; ptr++)
 97		if (data->states[ptr].gpios == data->state)
 98			return data->states[ptr].value;
 99
100	return -EINVAL;
101}
102
103static int gpio_regulator_set_value(struct regulator_dev *dev,
104					int min, int max, unsigned *selector)
105{
106	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
107	int ptr, target = 0, state, best_val = INT_MAX;
108
109	for (ptr = 0; ptr < data->nr_states; ptr++)
110		if (data->states[ptr].value < best_val &&
111		    data->states[ptr].value >= min &&
112		    data->states[ptr].value <= max) {
113			target = data->states[ptr].gpios;
114			best_val = data->states[ptr].value;
115			if (selector)
116				*selector = ptr;
117		}
118
119	if (best_val == INT_MAX)
120		return -EINVAL;
121
122	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
123		state = (target & (1 << ptr)) >> ptr;
124		gpio_set_value(data->gpios[ptr].gpio, state);
125	}
126	data->state = target;
127
128	return 0;
129}
130
131static int gpio_regulator_set_voltage(struct regulator_dev *dev,
132					int min_uV, int max_uV,
133					unsigned *selector)
134{
135	return gpio_regulator_set_value(dev, min_uV, max_uV, selector);
136}
137
138static int gpio_regulator_list_voltage(struct regulator_dev *dev,
139				      unsigned selector)
140{
141	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
142
143	if (selector >= data->nr_states)
144		return -EINVAL;
145
146	return data->states[selector].value;
147}
148
149static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
150					int min_uA, int max_uA)
151{
152	return gpio_regulator_set_value(dev, min_uA, max_uA, NULL);
153}
154
155static struct regulator_ops gpio_regulator_voltage_ops = {
156	.is_enabled = gpio_regulator_is_enabled,
157	.enable = gpio_regulator_enable,
158	.disable = gpio_regulator_disable,
159	.enable_time = gpio_regulator_enable_time,
160	.get_voltage = gpio_regulator_get_value,
161	.set_voltage = gpio_regulator_set_voltage,
162	.list_voltage = gpio_regulator_list_voltage,
163};
164
165static struct regulator_ops gpio_regulator_current_ops = {
166	.is_enabled = gpio_regulator_is_enabled,
167	.enable = gpio_regulator_enable,
168	.disable = gpio_regulator_disable,
169	.enable_time = gpio_regulator_enable_time,
170	.get_current_limit = gpio_regulator_get_value,
171	.set_current_limit = gpio_regulator_set_current_limit,
172};
173
174static int __devinit gpio_regulator_probe(struct platform_device *pdev)
175{
176	struct gpio_regulator_config *config = pdev->dev.platform_data;
177	struct gpio_regulator_data *drvdata;
178	struct regulator_config cfg = { };
179	int ptr, ret, state;
180
181	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
182			       GFP_KERNEL);
183	if (drvdata == NULL) {
184		dev_err(&pdev->dev, "Failed to allocate device data\n");
185		return -ENOMEM;
186	}
187
188	drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
189	if (drvdata->desc.name == NULL) {
190		dev_err(&pdev->dev, "Failed to allocate supply name\n");
191		ret = -ENOMEM;
192		goto err;
193	}
194
195	drvdata->gpios = kmemdup(config->gpios,
196				 config->nr_gpios * sizeof(struct gpio),
197				 GFP_KERNEL);
198	if (drvdata->gpios == NULL) {
199		dev_err(&pdev->dev, "Failed to allocate gpio data\n");
200		ret = -ENOMEM;
201		goto err_name;
202	}
203
204	drvdata->states = kmemdup(config->states,
205				  config->nr_states *
206					 sizeof(struct gpio_regulator_state),
207				  GFP_KERNEL);
208	if (drvdata->states == NULL) {
209		dev_err(&pdev->dev, "Failed to allocate state data\n");
210		ret = -ENOMEM;
211		goto err_memgpio;
212	}
213	drvdata->nr_states = config->nr_states;
214
215	drvdata->desc.owner = THIS_MODULE;
216
217	/* handle regulator type*/
218	switch (config->type) {
219	case REGULATOR_VOLTAGE:
220		drvdata->desc.type = REGULATOR_VOLTAGE;
221		drvdata->desc.ops = &gpio_regulator_voltage_ops;
222		drvdata->desc.n_voltages = config->nr_states;
223		break;
224	case REGULATOR_CURRENT:
225		drvdata->desc.type = REGULATOR_CURRENT;
226		drvdata->desc.ops = &gpio_regulator_current_ops;
227		break;
228	default:
229		dev_err(&pdev->dev, "No regulator type set\n");
230		ret = -EINVAL;
231		goto err_memgpio;
232		break;
233	}
234
235	drvdata->enable_gpio = config->enable_gpio;
236	drvdata->startup_delay = config->startup_delay;
237
238	if (gpio_is_valid(config->enable_gpio)) {
239		drvdata->enable_high = config->enable_high;
240
241		ret = gpio_request(config->enable_gpio, config->supply_name);
242		if (ret) {
243			dev_err(&pdev->dev,
244			   "Could not obtain regulator enable GPIO %d: %d\n",
245						config->enable_gpio, ret);
246			goto err_memstate;
247		}
248
249		/* set output direction without changing state
250		 * to prevent glitch
251		 */
252		if (config->enabled_at_boot) {
253			drvdata->is_enabled = true;
254			ret = gpio_direction_output(config->enable_gpio,
255						    config->enable_high);
256		} else {
257			drvdata->is_enabled = false;
258			ret = gpio_direction_output(config->enable_gpio,
259						    !config->enable_high);
260		}
261
262		if (ret) {
263			dev_err(&pdev->dev,
264			   "Could not configure regulator enable GPIO %d direction: %d\n",
265						config->enable_gpio, ret);
266			goto err_enablegpio;
267		}
268	} else {
269		/* Regulator without GPIO control is considered
270		 * always enabled
271		 */
272		drvdata->is_enabled = true;
273	}
274
275	drvdata->nr_gpios = config->nr_gpios;
276	ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
277	if (ret) {
278		dev_err(&pdev->dev,
279		   "Could not obtain regulator setting GPIOs: %d\n", ret);
280		goto err_enablegpio;
281	}
282
283	/* build initial state from gpio init data. */
284	state = 0;
285	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
286		if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
287			state |= (1 << ptr);
288	}
289	drvdata->state = state;
290
291	cfg.dev = &pdev->dev;
292	cfg.init_data = config->init_data;
293	cfg.driver_data = drvdata;
294
295	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
296	if (IS_ERR(drvdata->dev)) {
297		ret = PTR_ERR(drvdata->dev);
298		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
299		goto err_stategpio;
300	}
301
302	platform_set_drvdata(pdev, drvdata);
303
304	return 0;
305
306err_stategpio:
307	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
308err_enablegpio:
309	if (gpio_is_valid(config->enable_gpio))
310		gpio_free(config->enable_gpio);
311err_memstate:
312	kfree(drvdata->states);
313err_memgpio:
314	kfree(drvdata->gpios);
315err_name:
316	kfree(drvdata->desc.name);
317err:
318	return ret;
319}
320
321static int __devexit gpio_regulator_remove(struct platform_device *pdev)
322{
323	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
324
325	regulator_unregister(drvdata->dev);
326
327	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
328
329	kfree(drvdata->states);
330	kfree(drvdata->gpios);
331
332	if (gpio_is_valid(drvdata->enable_gpio))
333		gpio_free(drvdata->enable_gpio);
334
335	kfree(drvdata->desc.name);
336
337	return 0;
338}
339
340static struct platform_driver gpio_regulator_driver = {
341	.probe		= gpio_regulator_probe,
342	.remove		= __devexit_p(gpio_regulator_remove),
343	.driver		= {
344		.name		= "gpio-regulator",
345		.owner		= THIS_MODULE,
346	},
347};
348
349static int __init gpio_regulator_init(void)
350{
351	return platform_driver_register(&gpio_regulator_driver);
352}
353subsys_initcall(gpio_regulator_init);
354
355static void __exit gpio_regulator_exit(void)
356{
357	platform_driver_unregister(&gpio_regulator_driver);
358}
359module_exit(gpio_regulator_exit);
360
361MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
362MODULE_DESCRIPTION("gpio voltage regulator");
363MODULE_LICENSE("GPL");
364MODULE_ALIAS("platform:gpio-regulator");