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 
35 struct gpio_regulator_data {
36 	struct regulator_desc desc;
37 	struct regulator_dev *dev;
38 
39 	struct gpio *gpios;
40 	int nr_gpios;
41 
42 	struct gpio_regulator_state *states;
43 	int nr_states;
44 
45 	int state;
46 };
47 
48 static int gpio_regulator_get_value(struct regulator_dev *dev)
49 {
50 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
51 	int ptr;
52 
53 	for (ptr = 0; ptr < data->nr_states; ptr++)
54 		if (data->states[ptr].gpios == data->state)
55 			return data->states[ptr].value;
56 
57 	return -EINVAL;
58 }
59 
60 static int gpio_regulator_set_voltage(struct regulator_dev *dev,
61 					int min_uV, int max_uV,
62 					unsigned *selector)
63 {
64 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
65 	int ptr, target = 0, state, best_val = INT_MAX;
66 
67 	for (ptr = 0; ptr < data->nr_states; ptr++)
68 		if (data->states[ptr].value < best_val &&
69 		    data->states[ptr].value >= min_uV &&
70 		    data->states[ptr].value <= max_uV) {
71 			target = data->states[ptr].gpios;
72 			best_val = data->states[ptr].value;
73 			if (selector)
74 				*selector = ptr;
75 		}
76 
77 	if (best_val == INT_MAX)
78 		return -EINVAL;
79 
80 	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
81 		state = (target & (1 << ptr)) >> ptr;
82 		gpio_set_value(data->gpios[ptr].gpio, state);
83 	}
84 	data->state = target;
85 
86 	return 0;
87 }
88 
89 static int gpio_regulator_list_voltage(struct regulator_dev *dev,
90 				      unsigned selector)
91 {
92 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
93 
94 	if (selector >= data->nr_states)
95 		return -EINVAL;
96 
97 	return data->states[selector].value;
98 }
99 
100 static int gpio_regulator_set_current_limit(struct regulator_dev *dev,
101 					int min_uA, int max_uA)
102 {
103 	struct gpio_regulator_data *data = rdev_get_drvdata(dev);
104 	int ptr, target = 0, state, best_val = 0;
105 
106 	for (ptr = 0; ptr < data->nr_states; ptr++)
107 		if (data->states[ptr].value > best_val &&
108 		    data->states[ptr].value >= min_uA &&
109 		    data->states[ptr].value <= max_uA) {
110 			target = data->states[ptr].gpios;
111 			best_val = data->states[ptr].value;
112 		}
113 
114 	if (best_val == 0)
115 		return -EINVAL;
116 
117 	for (ptr = 0; ptr < data->nr_gpios; ptr++) {
118 		state = (target & (1 << ptr)) >> ptr;
119 		gpio_set_value(data->gpios[ptr].gpio, state);
120 	}
121 	data->state = target;
122 
123 	return 0;
124 }
125 
126 static struct regulator_ops gpio_regulator_voltage_ops = {
127 	.get_voltage = gpio_regulator_get_value,
128 	.set_voltage = gpio_regulator_set_voltage,
129 	.list_voltage = gpio_regulator_list_voltage,
130 };
131 
132 static struct regulator_ops gpio_regulator_current_ops = {
133 	.get_current_limit = gpio_regulator_get_value,
134 	.set_current_limit = gpio_regulator_set_current_limit,
135 };
136 
137 static int __devinit gpio_regulator_probe(struct platform_device *pdev)
138 {
139 	struct gpio_regulator_config *config = pdev->dev.platform_data;
140 	struct gpio_regulator_data *drvdata;
141 	struct regulator_config cfg = { };
142 	int ptr, ret, state;
143 
144 	drvdata = devm_kzalloc(&pdev->dev, sizeof(struct gpio_regulator_data),
145 			       GFP_KERNEL);
146 	if (drvdata == NULL) {
147 		dev_err(&pdev->dev, "Failed to allocate device data\n");
148 		return -ENOMEM;
149 	}
150 
151 	drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
152 	if (drvdata->desc.name == NULL) {
153 		dev_err(&pdev->dev, "Failed to allocate supply name\n");
154 		ret = -ENOMEM;
155 		goto err;
156 	}
157 
158 	drvdata->gpios = kmemdup(config->gpios,
159 				 config->nr_gpios * sizeof(struct gpio),
160 				 GFP_KERNEL);
161 	if (drvdata->gpios == NULL) {
162 		dev_err(&pdev->dev, "Failed to allocate gpio data\n");
163 		ret = -ENOMEM;
164 		goto err_name;
165 	}
166 
167 	drvdata->states = kmemdup(config->states,
168 				  config->nr_states *
169 					 sizeof(struct gpio_regulator_state),
170 				  GFP_KERNEL);
171 	if (drvdata->states == NULL) {
172 		dev_err(&pdev->dev, "Failed to allocate state data\n");
173 		ret = -ENOMEM;
174 		goto err_memgpio;
175 	}
176 	drvdata->nr_states = config->nr_states;
177 
178 	drvdata->desc.owner = THIS_MODULE;
179 	drvdata->desc.enable_time = config->startup_delay;
180 
181 	/* handle regulator type*/
182 	switch (config->type) {
183 	case REGULATOR_VOLTAGE:
184 		drvdata->desc.type = REGULATOR_VOLTAGE;
185 		drvdata->desc.ops = &gpio_regulator_voltage_ops;
186 		drvdata->desc.n_voltages = config->nr_states;
187 		break;
188 	case REGULATOR_CURRENT:
189 		drvdata->desc.type = REGULATOR_CURRENT;
190 		drvdata->desc.ops = &gpio_regulator_current_ops;
191 		break;
192 	default:
193 		dev_err(&pdev->dev, "No regulator type set\n");
194 		ret = -EINVAL;
195 		goto err_memgpio;
196 		break;
197 	}
198 
199 	drvdata->nr_gpios = config->nr_gpios;
200 	ret = gpio_request_array(drvdata->gpios, drvdata->nr_gpios);
201 	if (ret) {
202 		dev_err(&pdev->dev,
203 		   "Could not obtain regulator setting GPIOs: %d\n", ret);
204 		goto err_memstate;
205 	}
206 
207 	/* build initial state from gpio init data. */
208 	state = 0;
209 	for (ptr = 0; ptr < drvdata->nr_gpios; ptr++) {
210 		if (config->gpios[ptr].flags & GPIOF_OUT_INIT_HIGH)
211 			state |= (1 << ptr);
212 	}
213 	drvdata->state = state;
214 
215 	cfg.dev = &pdev->dev;
216 	cfg.init_data = config->init_data;
217 	cfg.driver_data = drvdata;
218 
219 	if (config->enable_gpio >= 0)
220 		cfg.ena_gpio = config->enable_gpio;
221 	cfg.ena_gpio_invert = !config->enable_high;
222 	if (config->enabled_at_boot) {
223 		if (config->enable_high)
224 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
225 		else
226 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
227 	} else {
228 		if (config->enable_high)
229 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
230 		else
231 			cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
232 	}
233 
234 	drvdata->dev = regulator_register(&drvdata->desc, &cfg);
235 	if (IS_ERR(drvdata->dev)) {
236 		ret = PTR_ERR(drvdata->dev);
237 		dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
238 		goto err_stategpio;
239 	}
240 
241 	platform_set_drvdata(pdev, drvdata);
242 
243 	return 0;
244 
245 err_stategpio:
246 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
247 err_memstate:
248 	kfree(drvdata->states);
249 err_memgpio:
250 	kfree(drvdata->gpios);
251 err_name:
252 	kfree(drvdata->desc.name);
253 err:
254 	return ret;
255 }
256 
257 static int __devexit gpio_regulator_remove(struct platform_device *pdev)
258 {
259 	struct gpio_regulator_data *drvdata = platform_get_drvdata(pdev);
260 
261 	regulator_unregister(drvdata->dev);
262 
263 	gpio_free_array(drvdata->gpios, drvdata->nr_gpios);
264 
265 	kfree(drvdata->states);
266 	kfree(drvdata->gpios);
267 
268 	kfree(drvdata->desc.name);
269 
270 	return 0;
271 }
272 
273 static struct platform_driver gpio_regulator_driver = {
274 	.probe		= gpio_regulator_probe,
275 	.remove		= __devexit_p(gpio_regulator_remove),
276 	.driver		= {
277 		.name		= "gpio-regulator",
278 		.owner		= THIS_MODULE,
279 	},
280 };
281 
282 static int __init gpio_regulator_init(void)
283 {
284 	return platform_driver_register(&gpio_regulator_driver);
285 }
286 subsys_initcall(gpio_regulator_init);
287 
288 static void __exit gpio_regulator_exit(void)
289 {
290 	platform_driver_unregister(&gpio_regulator_driver);
291 }
292 module_exit(gpio_regulator_exit);
293 
294 MODULE_AUTHOR("Heiko Stuebner <heiko@sntech.de>");
295 MODULE_DESCRIPTION("gpio voltage regulator");
296 MODULE_LICENSE("GPL");
297 MODULE_ALIAS("platform:gpio-regulator");
298