bd437c133b00e002dba965f3dac36e8bb9cf1b26
[linux-3.10.git] / drivers / regulator / fixed.c
1 /*
2  * fixed.c
3  *
4  * Copyright 2008 Wolfson Microelectronics PLC.
5  *
6  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
7  *
8  * Copyright (c) 2009 Nokia Corporation
9  * Roger Quadros <ext-roger.quadros@nokia.com>
10  *
11  * This program is free software; you can redistribute it and/or
12  * modify it under the terms of the GNU General Public License as
13  * published by the Free Software Foundation; either version 2 of the
14  * License, or (at your option) any later version.
15  *
16  * This is useful for systems with mixed controllable and
17  * non-controllable regulators, as well as for allowing testing on
18  * systems with no controllable regulators.
19  */
20
21 #include <linux/err.h>
22 #include <linux/mutex.h>
23 #include <linux/module.h>
24 #include <linux/platform_device.h>
25 #include <linux/regulator/driver.h>
26 #include <linux/regulator/fixed.h>
27 #include <linux/gpio.h>
28 #include <linux/slab.h>
29 #include <linux/of.h>
30 #include <linux/of_gpio.h>
31 #include <linux/regulator/of_regulator.h>
32 #include <linux/regulator/machine.h>
33
34 struct fixed_voltage_data {
35         struct regulator_desc desc;
36         struct regulator_dev *dev;
37         int microvolts;
38         int gpio;
39         unsigned startup_delay;
40         bool enable_high;
41         bool is_enabled;
42 };
43
44
45 /**
46  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
47  * @dev: device requesting for fixed_voltage_config
48  *
49  * Populates fixed_voltage_config structure by extracting data from device
50  * tree node, returns a pointer to the populated structure of NULL if memory
51  * alloc fails.
52  */
53 static struct fixed_voltage_config *
54 of_get_fixed_voltage_config(struct device *dev)
55 {
56         struct fixed_voltage_config *config;
57         struct device_node *np = dev->of_node;
58         const __be32 *delay;
59         struct regulator_init_data *init_data;
60
61         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
62                                                                  GFP_KERNEL);
63         if (!config)
64                 return NULL;
65
66         config->init_data = of_get_regulator_init_data(dev, dev->of_node);
67         if (!config->init_data)
68                 return NULL;
69
70         init_data = config->init_data;
71         init_data->constraints.apply_uV = 0;
72
73         config->supply_name = init_data->constraints.name;
74         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
75                 config->microvolts = init_data->constraints.min_uV;
76         } else {
77                 dev_err(dev,
78                          "Fixed regulator specified with variable voltages\n");
79                 return NULL;
80         }
81
82         if (init_data->constraints.boot_on)
83                 config->enabled_at_boot = true;
84
85         config->gpio = of_get_named_gpio(np, "gpio", 0);
86         delay = of_get_property(np, "startup-delay-us", NULL);
87         if (delay)
88                 config->startup_delay = be32_to_cpu(*delay);
89
90         if (of_find_property(np, "enable-active-high", NULL))
91                 config->enable_high = true;
92
93         return config;
94 }
95
96 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
97 {
98         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
99
100         return data->is_enabled;
101 }
102
103 static int fixed_voltage_enable(struct regulator_dev *dev)
104 {
105         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
106
107         gpio_set_value_cansleep(data->gpio, data->enable_high);
108         data->is_enabled = true;
109
110         return 0;
111 }
112
113 static int fixed_voltage_disable(struct regulator_dev *dev)
114 {
115         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
116
117         gpio_set_value_cansleep(data->gpio, !data->enable_high);
118         data->is_enabled = false;
119
120         return 0;
121 }
122
123 static int fixed_voltage_enable_time(struct regulator_dev *dev)
124 {
125         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
126
127         return data->startup_delay;
128 }
129
130 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
131 {
132         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
133
134         if (data->microvolts)
135                 return data->microvolts;
136         else
137                 return -EINVAL;
138 }
139
140 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
141                                       unsigned selector)
142 {
143         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
144
145         if (selector != 0)
146                 return -EINVAL;
147
148         return data->microvolts;
149 }
150
151 static struct regulator_ops fixed_voltage_gpio_ops = {
152         .is_enabled = fixed_voltage_is_enabled,
153         .enable = fixed_voltage_enable,
154         .disable = fixed_voltage_disable,
155         .enable_time = fixed_voltage_enable_time,
156         .get_voltage = fixed_voltage_get_voltage,
157         .list_voltage = fixed_voltage_list_voltage,
158 };
159
160 static struct regulator_ops fixed_voltage_ops = {
161         .get_voltage = fixed_voltage_get_voltage,
162         .list_voltage = fixed_voltage_list_voltage,
163 };
164
165 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
166 {
167         struct fixed_voltage_config *config;
168         struct fixed_voltage_data *drvdata;
169         struct regulator_config cfg = { };
170         int ret;
171
172         if (pdev->dev.of_node)
173                 config = of_get_fixed_voltage_config(&pdev->dev);
174         else
175                 config = pdev->dev.platform_data;
176
177         if (!config)
178                 return -ENOMEM;
179
180         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
181                                GFP_KERNEL);
182         if (drvdata == NULL) {
183                 dev_err(&pdev->dev, "Failed to allocate device data\n");
184                 ret = -ENOMEM;
185                 goto err;
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         drvdata->desc.type = REGULATOR_VOLTAGE;
195         drvdata->desc.owner = THIS_MODULE;
196
197         if (config->microvolts)
198                 drvdata->desc.n_voltages = 1;
199
200         drvdata->microvolts = config->microvolts;
201         drvdata->gpio = config->gpio;
202         drvdata->startup_delay = config->startup_delay;
203
204         if (gpio_is_valid(config->gpio)) {
205                 int gpio_flag;
206                 drvdata->enable_high = config->enable_high;
207
208                 /* FIXME: Remove below print warning
209                  *
210                  * config->gpio must be set to -EINVAL by platform code if
211                  * GPIO control is not required. However, early adopters
212                  * not requiring GPIO control may forget to initialize
213                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
214                  * for GPIO control.
215                  *
216                  * This warning will be removed once there are a couple of users
217                  * for this driver.
218                  */
219                 if (!config->gpio)
220                         dev_warn(&pdev->dev,
221                                 "using GPIO 0 for regulator enable control\n");
222
223                 /*
224                  * set output direction without changing state
225                  * to prevent glitch
226                  */
227                 drvdata->is_enabled = config->enabled_at_boot;
228                 ret = drvdata->is_enabled ?
229                                 config->enable_high : !config->enable_high;
230                 gpio_flag = ret ? GPIOF_OUT_INIT_HIGH : GPIOF_OUT_INIT_LOW;
231
232                 if (config->gpio_is_open_drain)
233                         gpio_flag |= GPIOF_OPEN_DRAIN;
234
235                 ret = gpio_request_one(config->gpio, gpio_flag,
236                                                 config->supply_name);
237                 if (ret) {
238                         dev_err(&pdev->dev,
239                            "Could not obtain regulator enable GPIO %d: %d\n",
240                                                         config->gpio, ret);
241                         goto err_name;
242                 }
243
244                 drvdata->desc.ops = &fixed_voltage_gpio_ops;
245
246         } else {
247                 drvdata->desc.ops = &fixed_voltage_ops;
248         }
249
250         cfg.dev = &pdev->dev;
251         cfg.init_data = config->init_data;
252         cfg.driver_data = drvdata;
253         cfg.of_node = pdev->dev.of_node;
254
255         drvdata->dev = regulator_register(&drvdata->desc, &cfg);
256         if (IS_ERR(drvdata->dev)) {
257                 ret = PTR_ERR(drvdata->dev);
258                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
259                 goto err_gpio;
260         }
261
262         platform_set_drvdata(pdev, drvdata);
263
264         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
265                 drvdata->microvolts);
266
267         return 0;
268
269 err_gpio:
270         if (gpio_is_valid(config->gpio))
271                 gpio_free(config->gpio);
272 err_name:
273         kfree(drvdata->desc.name);
274 err:
275         return ret;
276 }
277
278 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
279 {
280         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
281
282         regulator_unregister(drvdata->dev);
283         if (gpio_is_valid(drvdata->gpio))
284                 gpio_free(drvdata->gpio);
285         kfree(drvdata->desc.name);
286
287         return 0;
288 }
289
290 #if defined(CONFIG_OF)
291 static const struct of_device_id fixed_of_match[] __devinitconst = {
292         { .compatible = "regulator-fixed", },
293         {},
294 };
295 MODULE_DEVICE_TABLE(of, fixed_of_match);
296 #else
297 #define fixed_of_match NULL
298 #endif
299
300 static struct platform_driver regulator_fixed_voltage_driver = {
301         .probe          = reg_fixed_voltage_probe,
302         .remove         = __devexit_p(reg_fixed_voltage_remove),
303         .driver         = {
304                 .name           = "reg-fixed-voltage",
305                 .owner          = THIS_MODULE,
306                 .of_match_table = fixed_of_match,
307         },
308 };
309
310 static int __init regulator_fixed_voltage_init(void)
311 {
312         return platform_driver_register(&regulator_fixed_voltage_driver);
313 }
314 subsys_initcall(regulator_fixed_voltage_init);
315
316 static void __exit regulator_fixed_voltage_exit(void)
317 {
318         platform_driver_unregister(&regulator_fixed_voltage_driver);
319 }
320 module_exit(regulator_fixed_voltage_exit);
321
322 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
323 MODULE_DESCRIPTION("Fixed voltage regulator");
324 MODULE_LICENSE("GPL");
325 MODULE_ALIAS("platform:reg-fixed-voltage");