regulator: fixed: add support for ACPI interface
[sfrench/cifs-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/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 #include <linux/acpi.h>
34 #include <linux/property.h>
35 #include <linux/gpio/consumer.h>
36
37 struct fixed_voltage_data {
38         struct regulator_desc desc;
39         struct regulator_dev *dev;
40 };
41
42
43 /**
44  * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
45  * @dev: device requesting for fixed_voltage_config
46  * @desc: regulator description
47  *
48  * Populates fixed_voltage_config structure by extracting data from device
49  * tree node, returns a pointer to the populated structure of NULL if memory
50  * alloc fails.
51  */
52 static struct fixed_voltage_config *
53 of_get_fixed_voltage_config(struct device *dev,
54                             const struct regulator_desc *desc)
55 {
56         struct fixed_voltage_config *config;
57         struct device_node *np = dev->of_node;
58         struct regulator_init_data *init_data;
59
60         config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
61                                                                  GFP_KERNEL);
62         if (!config)
63                 return ERR_PTR(-ENOMEM);
64
65         config->init_data = of_get_regulator_init_data(dev, dev->of_node, desc);
66         if (!config->init_data)
67                 return ERR_PTR(-EINVAL);
68
69         init_data = config->init_data;
70         init_data->constraints.apply_uV = 0;
71
72         config->supply_name = init_data->constraints.name;
73         if (init_data->constraints.min_uV == init_data->constraints.max_uV) {
74                 config->microvolts = init_data->constraints.min_uV;
75         } else {
76                 dev_err(dev,
77                          "Fixed regulator specified with variable voltages\n");
78                 return ERR_PTR(-EINVAL);
79         }
80
81         if (init_data->constraints.boot_on)
82                 config->enabled_at_boot = true;
83
84         config->gpio = of_get_named_gpio(np, "gpio", 0);
85         if ((config->gpio < 0) && (config->gpio != -ENOENT))
86                 return ERR_PTR(config->gpio);
87
88         of_property_read_u32(np, "startup-delay-us", &config->startup_delay);
89
90         config->enable_high = of_property_read_bool(np, "enable-active-high");
91         config->gpio_is_open_drain = of_property_read_bool(np,
92                                                            "gpio-open-drain");
93
94         if (of_find_property(np, "vin-supply", NULL))
95                 config->input_supply = "vin";
96
97         return config;
98 }
99
100 /**
101  * acpi_get_fixed_voltage_config - extract fixed_voltage_config structure info
102  * @dev: device requesting for fixed_voltage_config
103  * @desc: regulator description
104  *
105  * Populates fixed_voltage_config structure by extracting data through ACPI
106  * interface, returns a pointer to the populated structure of NULL if memory
107  * alloc fails.
108  */
109 static struct fixed_voltage_config *
110 acpi_get_fixed_voltage_config(struct device *dev,
111                               const struct regulator_desc *desc)
112 {
113         struct fixed_voltage_config *config;
114         const char *supply_name;
115         struct gpio_desc *gpiod;
116         int ret;
117
118         config = devm_kzalloc(dev, sizeof(*config), GFP_KERNEL);
119         if (!config)
120                 return ERR_PTR(-ENOMEM);
121
122         ret = device_property_read_string(dev, "supply-name", &supply_name);
123         if (!ret)
124                 config->supply_name = supply_name;
125
126         gpiod = gpiod_get(dev, "gpio", GPIOD_ASIS);
127         if (IS_ERR(gpiod))
128                 return ERR_PTR(-ENODEV);
129
130         config->gpio = desc_to_gpio(gpiod);
131         config->enable_high = device_property_read_bool(dev,
132                                                         "enable-active-high");
133         gpiod_put(gpiod);
134
135         return config;
136 }
137
138 static struct regulator_ops fixed_voltage_ops = {
139 };
140
141 static int reg_fixed_voltage_probe(struct platform_device *pdev)
142 {
143         struct fixed_voltage_config *config;
144         struct fixed_voltage_data *drvdata;
145         struct regulator_config cfg = { };
146         int ret;
147
148         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
149                                GFP_KERNEL);
150         if (!drvdata)
151                 return -ENOMEM;
152
153         if (pdev->dev.of_node) {
154                 config = of_get_fixed_voltage_config(&pdev->dev,
155                                                      &drvdata->desc);
156                 if (IS_ERR(config))
157                         return PTR_ERR(config);
158         } else if (ACPI_HANDLE(&pdev->dev)) {
159                 config = acpi_get_fixed_voltage_config(&pdev->dev,
160                                                        &drvdata->desc);
161                 if (IS_ERR(config))
162                         return PTR_ERR(config);
163         } else {
164                 config = dev_get_platdata(&pdev->dev);
165         }
166
167         if (!config)
168                 return -ENOMEM;
169
170         drvdata->desc.name = devm_kstrdup(&pdev->dev,
171                                           config->supply_name,
172                                           GFP_KERNEL);
173         if (drvdata->desc.name == NULL) {
174                 dev_err(&pdev->dev, "Failed to allocate supply name\n");
175                 return -ENOMEM;
176         }
177         drvdata->desc.type = REGULATOR_VOLTAGE;
178         drvdata->desc.owner = THIS_MODULE;
179         drvdata->desc.ops = &fixed_voltage_ops;
180
181         drvdata->desc.enable_time = config->startup_delay;
182
183         if (config->input_supply) {
184                 drvdata->desc.supply_name = devm_kstrdup(&pdev->dev,
185                                             config->input_supply,
186                                             GFP_KERNEL);
187                 if (!drvdata->desc.supply_name) {
188                         dev_err(&pdev->dev,
189                                 "Failed to allocate input supply\n");
190                         return -ENOMEM;
191                 }
192         }
193
194         if (config->microvolts)
195                 drvdata->desc.n_voltages = 1;
196
197         drvdata->desc.fixed_uV = config->microvolts;
198
199         if (gpio_is_valid(config->gpio)) {
200                 cfg.ena_gpio = config->gpio;
201                 if (pdev->dev.of_node)
202                         cfg.ena_gpio_initialized = true;
203         }
204         cfg.ena_gpio_invert = !config->enable_high;
205         if (config->enabled_at_boot) {
206                 if (config->enable_high)
207                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
208                 else
209                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
210         } else {
211                 if (config->enable_high)
212                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
213                 else
214                         cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
215         }
216         if (config->gpio_is_open_drain)
217                 cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
218
219         cfg.dev = &pdev->dev;
220         cfg.init_data = config->init_data;
221         cfg.driver_data = drvdata;
222         cfg.of_node = pdev->dev.of_node;
223
224         drvdata->dev = devm_regulator_register(&pdev->dev, &drvdata->desc,
225                                                &cfg);
226         if (IS_ERR(drvdata->dev)) {
227                 ret = PTR_ERR(drvdata->dev);
228                 dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
229                 return ret;
230         }
231
232         platform_set_drvdata(pdev, drvdata);
233
234         dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
235                 drvdata->desc.fixed_uV);
236
237         return 0;
238 }
239
240 #if defined(CONFIG_OF)
241 static const struct of_device_id fixed_of_match[] = {
242         { .compatible = "regulator-fixed", },
243         {},
244 };
245 MODULE_DEVICE_TABLE(of, fixed_of_match);
246 #endif
247
248 static struct platform_driver regulator_fixed_voltage_driver = {
249         .probe          = reg_fixed_voltage_probe,
250         .driver         = {
251                 .name           = "reg-fixed-voltage",
252                 .of_match_table = of_match_ptr(fixed_of_match),
253         },
254 };
255
256 static int __init regulator_fixed_voltage_init(void)
257 {
258         return platform_driver_register(&regulator_fixed_voltage_driver);
259 }
260 subsys_initcall(regulator_fixed_voltage_init);
261
262 static void __exit regulator_fixed_voltage_exit(void)
263 {
264         platform_driver_unregister(&regulator_fixed_voltage_driver);
265 }
266 module_exit(regulator_fixed_voltage_exit);
267
268 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
269 MODULE_DESCRIPTION("Fixed voltage regulator");
270 MODULE_LICENSE("GPL");
271 MODULE_ALIAS("platform:reg-fixed-voltage");