i2c-stu300: make sure adapter-name is terminated
[linux-2.6.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/platform_device.h>
24 #include <linux/regulator/driver.h>
25 #include <linux/regulator/fixed.h>
26 #include <linux/gpio.h>
27 #include <linux/delay.h>
28 #include <linux/slab.h>
29
30 struct fixed_voltage_data {
31         struct regulator_desc desc;
32         struct regulator_dev *dev;
33         int microvolts;
34         int gpio;
35         unsigned startup_delay;
36         bool enable_high;
37         bool is_enabled;
38 };
39
40 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
41 {
42         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
43
44         return data->is_enabled;
45 }
46
47 static int fixed_voltage_enable(struct regulator_dev *dev)
48 {
49         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
50
51         if (gpio_is_valid(data->gpio)) {
52                 gpio_set_value_cansleep(data->gpio, data->enable_high);
53                 data->is_enabled = true;
54         }
55
56         return 0;
57 }
58
59 static int fixed_voltage_disable(struct regulator_dev *dev)
60 {
61         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
62
63         if (gpio_is_valid(data->gpio)) {
64                 gpio_set_value_cansleep(data->gpio, !data->enable_high);
65                 data->is_enabled = false;
66         }
67
68         return 0;
69 }
70
71 static int fixed_voltage_enable_time(struct regulator_dev *dev)
72 {
73         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
74
75         return data->startup_delay;
76 }
77
78 static int fixed_voltage_get_voltage(struct regulator_dev *dev)
79 {
80         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
81
82         return data->microvolts;
83 }
84
85 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
86                                       unsigned selector)
87 {
88         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
89
90         if (selector != 0)
91                 return -EINVAL;
92
93         return data->microvolts;
94 }
95
96 static struct regulator_ops fixed_voltage_ops = {
97         .is_enabled = fixed_voltage_is_enabled,
98         .enable = fixed_voltage_enable,
99         .disable = fixed_voltage_disable,
100         .enable_time = fixed_voltage_enable_time,
101         .get_voltage = fixed_voltage_get_voltage,
102         .list_voltage = fixed_voltage_list_voltage,
103 };
104
105 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
106 {
107         struct fixed_voltage_config *config = pdev->dev.platform_data;
108         struct fixed_voltage_data *drvdata;
109         int ret;
110
111         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
112         if (drvdata == NULL) {
113                 dev_err(&pdev->dev, "Failed to allocate device data\n");
114                 ret = -ENOMEM;
115                 goto err;
116         }
117
118         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
119         if (drvdata->desc.name == NULL) {
120                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
121                 ret = -ENOMEM;
122                 goto err;
123         }
124         drvdata->desc.type = REGULATOR_VOLTAGE;
125         drvdata->desc.owner = THIS_MODULE;
126         drvdata->desc.ops = &fixed_voltage_ops;
127         drvdata->desc.n_voltages = 1;
128
129         drvdata->microvolts = config->microvolts;
130         drvdata->gpio = config->gpio;
131         drvdata->startup_delay = config->startup_delay;
132
133         if (gpio_is_valid(config->gpio)) {
134                 drvdata->enable_high = config->enable_high;
135
136                 /* FIXME: Remove below print warning
137                  *
138                  * config->gpio must be set to -EINVAL by platform code if
139                  * GPIO control is not required. However, early adopters
140                  * not requiring GPIO control may forget to initialize
141                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
142                  * for GPIO control.
143                  *
144                  * This warning will be removed once there are a couple of users
145                  * for this driver.
146                  */
147                 if (!config->gpio)
148                         dev_warn(&pdev->dev,
149                                 "using GPIO 0 for regulator enable control\n");
150
151                 ret = gpio_request(config->gpio, config->supply_name);
152                 if (ret) {
153                         dev_err(&pdev->dev,
154                            "Could not obtain regulator enable GPIO %d: %d\n",
155                                                         config->gpio, ret);
156                         goto err_name;
157                 }
158
159                 /* set output direction without changing state
160                  * to prevent glitch
161                  */
162                 drvdata->is_enabled = config->enabled_at_boot;
163                 ret = drvdata->is_enabled ?
164                                 config->enable_high : !config->enable_high;
165
166                 ret = gpio_direction_output(config->gpio, ret);
167                 if (ret) {
168                         dev_err(&pdev->dev,
169                            "Could not configure regulator enable GPIO %d direction: %d\n",
170                                                         config->gpio, ret);
171                         goto err_gpio;
172                 }
173
174         } else {
175                 /* Regulator without GPIO control is considered
176                  * always enabled
177                  */
178                 drvdata->is_enabled = true;
179         }
180
181         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
182                                           config->init_data, drvdata);
183         if (IS_ERR(drvdata->dev)) {
184                 ret = PTR_ERR(drvdata->dev);
185                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
186                 goto err_gpio;
187         }
188
189         platform_set_drvdata(pdev, drvdata);
190
191         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
192                 drvdata->microvolts);
193
194         return 0;
195
196 err_gpio:
197         if (gpio_is_valid(config->gpio))
198                 gpio_free(config->gpio);
199 err_name:
200         kfree(drvdata->desc.name);
201 err:
202         kfree(drvdata);
203         return ret;
204 }
205
206 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
207 {
208         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
209
210         regulator_unregister(drvdata->dev);
211         if (gpio_is_valid(drvdata->gpio))
212                 gpio_free(drvdata->gpio);
213         kfree(drvdata->desc.name);
214         kfree(drvdata);
215
216         return 0;
217 }
218
219 static struct platform_driver regulator_fixed_voltage_driver = {
220         .probe          = reg_fixed_voltage_probe,
221         .remove         = __devexit_p(reg_fixed_voltage_remove),
222         .driver         = {
223                 .name           = "reg-fixed-voltage",
224                 .owner          = THIS_MODULE,
225         },
226 };
227
228 static int __init regulator_fixed_voltage_init(void)
229 {
230         return platform_driver_register(&regulator_fixed_voltage_driver);
231 }
232 subsys_initcall(regulator_fixed_voltage_init);
233
234 static void __exit regulator_fixed_voltage_exit(void)
235 {
236         platform_driver_unregister(&regulator_fixed_voltage_driver);
237 }
238 module_exit(regulator_fixed_voltage_exit);
239
240 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
241 MODULE_DESCRIPTION("Fixed voltage regulator");
242 MODULE_LICENSE("GPL");
243 MODULE_ALIAS("platform:reg-fixed-voltage");