regulator: Staticise of_get_fixed_voltage_config()
[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/delay.h>
29 #include <linux/slab.h>
30 #include <linux/of.h>
31 #include <linux/of_gpio.h>
32 #include <linux/regulator/of_regulator.h>
33 #include <linux/regulator/machine.h>
34
35 struct fixed_voltage_data {
36         struct regulator_desc desc;
37         struct regulator_dev *dev;
38         int microvolts;
39         int gpio;
40         unsigned startup_delay;
41         bool enable_high;
42         bool is_enabled;
43 };
44
45
46 /**
47  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
48  * @dev: device requesting for fixed_voltage_config
49  *
50  * Populates fixed_voltage_config structure by extracting data from device
51  * tree node, returns a pointer to the populated structure of NULL if memory
52  * alloc fails.
53  */
54 static struct fixed_voltage_config *
55 of_get_fixed_voltage_config(struct device *dev)
56 {
57         struct fixed_voltage_config *config;
58         struct device_node *np = dev->of_node;
59         const __be32 *delay;
60         struct regulator_init_data *init_data;
61
62         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
63                                                                  GFP_KERNEL);
64         if (!config)
65                 return NULL;
66
67         config->init_data = of_get_regulator_init_data(dev);
68         if (!config->init_data)
69                 return NULL;
70
71         init_data = config->init_data;
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         if (gpio_is_valid(data->gpio)) {
108                 gpio_set_value_cansleep(data->gpio, data->enable_high);
109                 data->is_enabled = true;
110         }
111
112         return 0;
113 }
114
115 static int fixed_voltage_disable(struct regulator_dev *dev)
116 {
117         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
118
119         if (gpio_is_valid(data->gpio)) {
120                 gpio_set_value_cansleep(data->gpio, !data->enable_high);
121                 data->is_enabled = false;
122         }
123
124         return 0;
125 }
126
127 static int fixed_voltage_enable_time(struct regulator_dev *dev)
128 {
129         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
130
131         return data->startup_delay;
132 }
133
134 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
135 {
136         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
137
138         return data->microvolts;
139 }
140
141 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
142                                       unsigned selector)
143 {
144         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
145
146         if (selector != 0)
147                 return -EINVAL;
148
149         return data->microvolts;
150 }
151
152 static struct regulator_ops fixed_voltage_ops = {
153         .is_enabled = fixed_voltage_is_enabled,
154         .enable = fixed_voltage_enable,
155         .disable = fixed_voltage_disable,
156         .enable_time = fixed_voltage_enable_time,
157         .get_voltage = fixed_voltage_get_voltage,
158         .list_voltage = fixed_voltage_list_voltage,
159 };
160
161 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
162 {
163         struct fixed_voltage_config *config = pdev->dev.platform_data;
164         struct fixed_voltage_data *drvdata;
165         int ret;
166
167         if (pdev->dev.of_node)
168                 config = of_get_fixed_voltage_config(&pdev->dev);
169
170         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
171         if (drvdata == NULL) {
172                 dev_err(&pdev->dev, "Failed to allocate device data\n");
173                 ret = -ENOMEM;
174                 goto err;
175         }
176
177         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
178         if (drvdata->desc.name == NULL) {
179                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
180                 ret = -ENOMEM;
181                 goto err;
182         }
183         drvdata->desc.type = REGULATOR_VOLTAGE;
184         drvdata->desc.owner = THIS_MODULE;
185         drvdata->desc.ops = &fixed_voltage_ops;
186         drvdata->desc.n_voltages = 1;
187
188         drvdata->microvolts = config->microvolts;
189         drvdata->gpio = config->gpio;
190         drvdata->startup_delay = config->startup_delay;
191
192         if (gpio_is_valid(config->gpio)) {
193                 drvdata->enable_high = config->enable_high;
194
195                 /* FIXME: Remove below print warning
196                  *
197                  * config->gpio must be set to -EINVAL by platform code if
198                  * GPIO control is not required. However, early adopters
199                  * not requiring GPIO control may forget to initialize
200                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
201                  * for GPIO control.
202                  *
203                  * This warning will be removed once there are a couple of users
204                  * for this driver.
205                  */
206                 if (!config->gpio)
207                         dev_warn(&pdev->dev,
208                                 "using GPIO 0 for regulator enable control\n");
209
210                 ret = gpio_request(config->gpio, config->supply_name);
211                 if (ret) {
212                         dev_err(&pdev->dev,
213                            "Could not obtain regulator enable GPIO %d: %d\n",
214                                                         config->gpio, ret);
215                         goto err_name;
216                 }
217
218                 /* set output direction without changing state
219                  * to prevent glitch
220                  */
221                 drvdata->is_enabled = config->enabled_at_boot;
222                 ret = drvdata->is_enabled ?
223                                 config->enable_high : !config->enable_high;
224
225                 ret = gpio_direction_output(config->gpio, ret);
226                 if (ret) {
227                         dev_err(&pdev->dev,
228                            "Could not configure regulator enable GPIO %d direction: %d\n",
229                                                         config->gpio, ret);
230                         goto err_gpio;
231                 }
232
233         } else {
234                 /* Regulator without GPIO control is considered
235                  * always enabled
236                  */
237                 drvdata->is_enabled = true;
238         }
239
240         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
241                                           config->init_data, drvdata, NULL);
242         if (IS_ERR(drvdata->dev)) {
243                 ret = PTR_ERR(drvdata->dev);
244                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
245                 goto err_gpio;
246         }
247
248         platform_set_drvdata(pdev, drvdata);
249
250         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
251                 drvdata->microvolts);
252
253         return 0;
254
255 err_gpio:
256         if (gpio_is_valid(config->gpio))
257                 gpio_free(config->gpio);
258 err_name:
259         kfree(drvdata->desc.name);
260 err:
261         kfree(drvdata);
262         return ret;
263 }
264
265 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
266 {
267         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
268
269         regulator_unregister(drvdata->dev);
270         if (gpio_is_valid(drvdata->gpio))
271                 gpio_free(drvdata->gpio);
272         kfree(drvdata->desc.name);
273         kfree(drvdata);
274
275         return 0;
276 }
277
278 #if defined(CONFIG_OF)
279 static const struct of_device_id fixed_of_match[] __devinitconst = {
280         { .compatible = "regulator-fixed", },
281         {},
282 };
283 MODULE_DEVICE_TABLE(of, fixed_of_match);
284 #else
285 #define fixed_of_match NULL
286 #endif
287
288 static struct platform_driver regulator_fixed_voltage_driver = {
289         .probe          = reg_fixed_voltage_probe,
290         .remove         = __devexit_p(reg_fixed_voltage_remove),
291         .driver         = {
292                 .name           = "reg-fixed-voltage",
293                 .owner          = THIS_MODULE,
294                 .of_match_table = fixed_of_match,
295         },
296 };
297
298 static int __init regulator_fixed_voltage_init(void)
299 {
300         return platform_driver_register(&regulator_fixed_voltage_driver);
301 }
302 subsys_initcall(regulator_fixed_voltage_init);
303
304 static void __exit regulator_fixed_voltage_exit(void)
305 {
306         platform_driver_unregister(&regulator_fixed_voltage_driver);
307 }
308 module_exit(regulator_fixed_voltage_exit);
309
310 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
311 MODULE_DESCRIPTION("Fixed voltage regulator");
312 MODULE_LICENSE("GPL");
313 MODULE_ALIAS("platform:reg-fixed-voltage");