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 struct fixed_voltage_config *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);
67         init_data = config->init_data;
68
69         config->supply_name = init_data->constraints.name;
70         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
71                 config->microvolts = init_data->constraints.min_uV;
72         } else {
73                 dev_err(dev,
74                          "Fixed regulator specified with variable voltages\n");
75                 return NULL;
76         }
77
78         if (init_data->constraints.boot_on)
79                 config->enabled_at_boot = true;
80
81         config->gpio = of_get_named_gpio(np, "gpio", 0);
82         delay = of_get_property(np, "startup-delay-us", NULL);
83         if (delay)
84                 config->startup_delay = be32_to_cpu(*delay);
85
86         if (of_find_property(np, "enable-active-high", NULL))
87                 config->enable_high = true;
88
89         return config;
90 }
91
92 static int fixed_voltage_is_enabled(struct regulator_dev *dev)
93 {
94         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
95
96         return data->is_enabled;
97 }
98
99 static int fixed_voltage_enable(struct regulator_dev *dev)
100 {
101         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
102
103         if (gpio_is_valid(data->gpio)) {
104                 gpio_set_value_cansleep(data->gpio, data->enable_high);
105                 data->is_enabled = true;
106         }
107
108         return 0;
109 }
110
111 static int fixed_voltage_disable(struct regulator_dev *dev)
112 {
113         struct fixed_voltage_data *data = rdev_get_drvdata(dev);
114
115         if (gpio_is_valid(data->gpio)) {
116                 gpio_set_value_cansleep(data->gpio, !data->enable_high);
117                 data->is_enabled = false;
118         }
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_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 int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
161 {
162         struct fixed_voltage_config *config = pdev->dev.platform_data;
163         struct fixed_voltage_data *drvdata;
164         int ret;
165
166         if (pdev->dev.of_node)
167                 config = of_get_fixed_voltage_config(&pdev->dev);
168
169         drvdata = kzalloc(sizeof(struct fixed_voltage_data), GFP_KERNEL);
170         if (drvdata == NULL) {
171                 dev_err(&pdev->dev, "Failed to allocate device data\n");
172                 ret = -ENOMEM;
173                 goto err;
174         }
175
176         drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
177         if (drvdata->desc.name == NULL) {
178                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
179                 ret = -ENOMEM;
180                 goto err;
181         }
182         drvdata->desc.type = REGULATOR_VOLTAGE;
183         drvdata->desc.owner = THIS_MODULE;
184         drvdata->desc.ops = &fixed_voltage_ops;
185         drvdata->desc.n_voltages = 1;
186
187         drvdata->microvolts = config->microvolts;
188         drvdata->gpio = config->gpio;
189         drvdata->startup_delay = config->startup_delay;
190
191         if (gpio_is_valid(config->gpio)) {
192                 drvdata->enable_high = config->enable_high;
193
194                 /* FIXME: Remove below print warning
195                  *
196                  * config->gpio must be set to -EINVAL by platform code if
197                  * GPIO control is not required. However, early adopters
198                  * not requiring GPIO control may forget to initialize
199                  * config->gpio to -EINVAL. This will cause GPIO 0 to be used
200                  * for GPIO control.
201                  *
202                  * This warning will be removed once there are a couple of users
203                  * for this driver.
204                  */
205                 if (!config->gpio)
206                         dev_warn(&pdev->dev,
207                                 "using GPIO 0 for regulator enable control\n");
208
209                 ret = gpio_request(config->gpio, config->supply_name);
210                 if (ret) {
211                         dev_err(&pdev->dev,
212                            "Could not obtain regulator enable GPIO %d: %d\n",
213                                                         config->gpio, ret);
214                         goto err_name;
215                 }
216
217                 /* set output direction without changing state
218                  * to prevent glitch
219                  */
220                 drvdata->is_enabled = config->enabled_at_boot;
221                 ret = drvdata->is_enabled ?
222                                 config->enable_high : !config->enable_high;
223
224                 ret = gpio_direction_output(config->gpio, ret);
225                 if (ret) {
226                         dev_err(&pdev->dev,
227                            "Could not configure regulator enable GPIO %d direction: %d\n",
228                                                         config->gpio, ret);
229                         goto err_gpio;
230                 }
231
232         } else {
233                 /* Regulator without GPIO control is considered
234                  * always enabled
235                  */
236                 drvdata->is_enabled = true;
237         }
238
239         drvdata->dev = regulator_register(&drvdata->desc, &pdev->dev,
240                                           config->init_data, drvdata, NULL);
241         if (IS_ERR(drvdata->dev)) {
242                 ret = PTR_ERR(drvdata->dev);
243                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
244                 goto err_gpio;
245         }
246
247         platform_set_drvdata(pdev, drvdata);
248
249         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
250                 drvdata->microvolts);
251
252         return 0;
253
254 err_gpio:
255         if (gpio_is_valid(config->gpio))
256                 gpio_free(config->gpio);
257 err_name:
258         kfree(drvdata->desc.name);
259 err:
260         kfree(drvdata);
261         return ret;
262 }
263
264 static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
265 {
266         struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
267
268         regulator_unregister(drvdata->dev);
269         if (gpio_is_valid(drvdata->gpio))
270                 gpio_free(drvdata->gpio);
271         kfree(drvdata->desc.name);
272         kfree(drvdata);
273
274         return 0;
275 }
276
277 #if defined(CONFIG_OF)
278 static const struct of_device_id fixed_of_match[] __devinitconst = {
279         { .compatible = "regulator-fixed", },
280         {},
281 };
282 MODULE_DEVICE_TABLE(of, fixed_of_match);
283 #else
284 #define fixed_of_match NULL
285 #endif
286
287 static struct platform_driver regulator_fixed_voltage_driver = {
288         .probe          = reg_fixed_voltage_probe,
289         .remove         = __devexit_p(reg_fixed_voltage_remove),
290         .driver         = {
291                 .name           = "reg-fixed-voltage",
292                 .owner          = THIS_MODULE,
293                 .of_match_table = fixed_of_match,
294         },
295 };
296
297 static int __init regulator_fixed_voltage_init(void)
298 {
299         return platform_driver_register(&regulator_fixed_voltage_driver);
300 }
301 subsys_initcall(regulator_fixed_voltage_init);
302
303 static void __exit regulator_fixed_voltage_exit(void)
304 {
305         platform_driver_unregister(&regulator_fixed_voltage_driver);
306 }
307 module_exit(regulator_fixed_voltage_exit);
308
309 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
310 MODULE_DESCRIPTION("Fixed voltage regulator");
311 MODULE_LICENSE("GPL");
312 MODULE_ALIAS("platform:reg-fixed-voltage");