Merge remote-tracking branch 'regulator/topic/dt' into regulator-next
[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         if (data->microvolts)
139                 return data->microvolts;
140         else
141                 return -EINVAL;
142 }
143
144 static int fixed_voltage_list_voltage(struct regulator_dev *dev,
145                                       unsigned selector)
146 {
147         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
148
149         if (selector != 0)
150                 return -EINVAL;
151
152         return data->microvolts;
153 }
154
155 static struct regulator_ops fixed_voltage_ops = {
156         .is_enabled = fixed_voltage_is_enabled,
157         .enable = fixed_voltage_enable,
158         .disable = fixed_voltage_disable,
159         .enable_time = fixed_voltage_enable_time,
160         .get_voltage = fixed_voltage_get_voltage,
161         .list_voltage = fixed_voltage_list_voltage,
162 };
163
164 static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
165 {
166         struct fixed_voltage_config *config = pdev->dev.platform_data;
167         struct fixed_voltage_data *drvdata;
168         int ret;
169
170         if (pdev->dev.of_node)
171                 config = of_get_fixed_voltage_config(&pdev->dev);
172
173         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
174         if (drvdata == NULL) {
175                 dev_err(&pdev->dev, "Failed to allocate device data\n");
176                 ret = -ENOMEM;
177                 goto err;
178         }
179
180         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
181         if (drvdata->desc.name == NULL) {
182                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
183                 ret = -ENOMEM;
184                 goto err;
185         }
186         drvdata->desc.type = REGULATOR_VOLTAGE;
187         drvdata->desc.owner = THIS_MODULE;
188         drvdata->desc.ops = &fixed_voltage_ops;
189         drvdata->desc.n_voltages = 1;
190
191         drvdata->microvolts = config->microvolts;
192         drvdata->gpio = config->gpio;
193         drvdata->startup_delay = config->startup_delay;
194
195         if (gpio_is_valid(config->gpio)) {
196                 drvdata->enable_high = config->enable_high;
197
198                 /* FIXME: Remove below print warning
199                  *
200                  * config->gpio must be set to -EINVAL by platform code if
201                  * GPIO control is not required. However, early adopters
202                  * not requiring GPIO control may forget to initialize
203                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
204                  * for GPIO control.
205                  *
206                  * This warning will be removed once there are a couple of users
207                  * for this driver.
208                  */
209                 if (!config->gpio)
210                         dev_warn(&pdev->dev,
211                                 "using GPIO 0 for regulator enable control\n");
212
213                 ret = gpio_request(config->gpio, config->supply_name);
214                 if (ret) {
215                         dev_err(&pdev->dev,
216                            "Could not obtain regulator enable GPIO %d: %d\n",
217                                                         config->gpio, ret);
218                         goto err_name;
219                 }
220
221                 /* set output direction without changing state
222                  * to prevent glitch
223                  */
224                 drvdata->is_enabled = config->enabled_at_boot;
225                 ret = drvdata->is_enabled ?
226                                 config->enable_high : !config->enable_high;
227
228                 ret = gpio_direction_output(config->gpio, ret);
229                 if (ret) {
230                         dev_err(&pdev->dev,
231                            "Could not configure regulator enable GPIO %d direction: %d\n",
232                                                         config->gpio, ret);
233                         goto err_gpio;
234                 }
235
236         } else {
237                 /* Regulator without GPIO control is considered
238                  * always enabled
239                  */
240                 drvdata->is_enabled = true;
241         }
242
243         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
244                                           config->init_data, drvdata, NULL);
245         if (IS_ERR(drvdata->dev)) {
246                 ret = PTR_ERR(drvdata->dev);
247                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
248                 goto err_gpio;
249         }
250
251         platform_set_drvdata(pdev, drvdata);
252
253         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
254                 drvdata->microvolts);
255
256         return 0;
257
258 err_gpio:
259         if (gpio_is_valid(config->gpio))
260                 gpio_free(config->gpio);
261 err_name:
262         kfree(drvdata->desc.name);
263 err:
264         kfree(drvdata);
265         return ret;
266 }
267
268 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
269 {
270         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
271
272         regulator_unregister(drvdata->dev);
273         if (gpio_is_valid(drvdata->gpio))
274                 gpio_free(drvdata->gpio);
275         kfree(drvdata->desc.name);
276         kfree(drvdata);
277
278         return 0;
279 }
280
281 #if defined(CONFIG_OF)
282 static const struct of_device_id fixed_of_match[] __devinitconst = {
283         { .compatible = "regulator-fixed", },
284         {},
285 };
286 MODULE_DEVICE_TABLE(of, fixed_of_match);
287 #else
288 #define fixed_of_match NULL
289 #endif
290
291 static struct platform_driver regulator_fixed_voltage_driver = {
292         .probe          = reg_fixed_voltage_probe,
293         .remove         = __devexit_p(reg_fixed_voltage_remove),
294         .driver         = {
295                 .name           = "reg-fixed-voltage",
296                 .owner          = THIS_MODULE,
297                 .of_match_table = fixed_of_match,
298         },
299 };
300
301 static int __init regulator_fixed_voltage_init(void)
302 {
303         return platform_driver_register(&regulator_fixed_voltage_driver);
304 }
305 subsys_initcall(regulator_fixed_voltage_init);
306
307 static void __exit regulator_fixed_voltage_exit(void)
308 {
309         platform_driver_unregister(&regulator_fixed_voltage_driver);
310 }
311 module_exit(regulator_fixed_voltage_exit);
312
313 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
314 MODULE_DESCRIPTION("Fixed voltage regulator");
315 MODULE_LICENSE("GPL");
316 MODULE_ALIAS("platform:reg-fixed-voltage");