Root/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
34struct fixed_voltage_data {
35    struct regulator_desc desc;
36    struct regulator_dev *dev;
37    int microvolts;
38};
39
40
41/**
42 * of_get_fixed_voltage_config - extract fixed_voltage_config structure info
43 * @dev: device requesting for fixed_voltage_config
44 *
45 * Populates fixed_voltage_config structure by extracting data from device
46 * tree node, returns a pointer to the populated structure of NULL if memory
47 * alloc fails.
48 */
49static struct fixed_voltage_config *
50of_get_fixed_voltage_config(struct device *dev)
51{
52    struct fixed_voltage_config *config;
53    struct device_node *np = dev->of_node;
54    const __be32 *delay;
55    struct regulator_init_data *init_data;
56
57    config = devm_kzalloc(dev, sizeof(struct fixed_voltage_config),
58                                 GFP_KERNEL);
59    if (!config)
60        return ERR_PTR(-ENOMEM);
61
62    config->init_data = of_get_regulator_init_data(dev, dev->of_node);
63    if (!config->init_data)
64        return ERR_PTR(-EINVAL);
65
66    init_data = config->init_data;
67    init_data->constraints.apply_uV = 0;
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 ERR_PTR(-EINVAL);
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    /*
83     * of_get_named_gpio() currently returns ENODEV rather than
84     * EPROBE_DEFER. This code attempts to be compatible with both
85     * for now; the ENODEV check can be removed once the API is fixed.
86     * of_get_named_gpio() doesn't differentiate between a missing
87     * property (which would be fine here, since the GPIO is optional)
88     * and some other error. Patches have been posted for both issues.
89     * Once they are check in, we should replace this with:
90     * if (config->gpio < 0 && config->gpio != -ENOENT)
91     */
92    if ((config->gpio == -ENODEV) || (config->gpio == -EPROBE_DEFER))
93        return ERR_PTR(-EPROBE_DEFER);
94
95    delay = of_get_property(np, "startup-delay-us", NULL);
96    if (delay)
97        config->startup_delay = be32_to_cpu(*delay);
98
99    if (of_find_property(np, "enable-active-high", NULL))
100        config->enable_high = true;
101
102    if (of_find_property(np, "gpio-open-drain", NULL))
103        config->gpio_is_open_drain = true;
104
105    if (of_find_property(np, "vin-supply", NULL))
106        config->input_supply = "vin";
107
108    return config;
109}
110
111static int fixed_voltage_get_voltage(struct regulator_dev *dev)
112{
113    struct fixed_voltage_data *data = rdev_get_drvdata(dev);
114
115    if (data->microvolts)
116        return data->microvolts;
117    else
118        return -EINVAL;
119}
120
121static int fixed_voltage_list_voltage(struct regulator_dev *dev,
122                      unsigned selector)
123{
124    struct fixed_voltage_data *data = rdev_get_drvdata(dev);
125
126    if (selector != 0)
127        return -EINVAL;
128
129    return data->microvolts;
130}
131
132static struct regulator_ops fixed_voltage_ops = {
133    .get_voltage = fixed_voltage_get_voltage,
134    .list_voltage = fixed_voltage_list_voltage,
135};
136
137static int __devinit reg_fixed_voltage_probe(struct platform_device *pdev)
138{
139    struct fixed_voltage_config *config;
140    struct fixed_voltage_data *drvdata;
141    struct regulator_config cfg = { };
142    int ret;
143
144    if (pdev->dev.of_node) {
145        config = of_get_fixed_voltage_config(&pdev->dev);
146        if (IS_ERR(config))
147            return PTR_ERR(config);
148    } else {
149        config = pdev->dev.platform_data;
150    }
151
152    if (!config)
153        return -ENOMEM;
154
155    drvdata = devm_kzalloc(&pdev->dev, sizeof(struct fixed_voltage_data),
156                   GFP_KERNEL);
157    if (drvdata == NULL) {
158        dev_err(&pdev->dev, "Failed to allocate device data\n");
159        ret = -ENOMEM;
160        goto err;
161    }
162
163    drvdata->desc.name = kstrdup(config->supply_name, GFP_KERNEL);
164    if (drvdata->desc.name == NULL) {
165        dev_err(&pdev->dev, "Failed to allocate supply name\n");
166        ret = -ENOMEM;
167        goto err;
168    }
169    drvdata->desc.type = REGULATOR_VOLTAGE;
170    drvdata->desc.owner = THIS_MODULE;
171    drvdata->desc.ops = &fixed_voltage_ops;
172
173    drvdata->desc.enable_time = config->startup_delay;
174
175    if (config->input_supply) {
176        drvdata->desc.supply_name = kstrdup(config->input_supply,
177                            GFP_KERNEL);
178        if (!drvdata->desc.supply_name) {
179            dev_err(&pdev->dev,
180                "Failed to allocate input supply\n");
181            ret = -ENOMEM;
182            goto err_name;
183        }
184    }
185
186    if (config->microvolts)
187        drvdata->desc.n_voltages = 1;
188
189    drvdata->microvolts = config->microvolts;
190
191    if (config->gpio >= 0)
192        cfg.ena_gpio = config->gpio;
193    cfg.ena_gpio_invert = !config->enable_high;
194    if (config->enabled_at_boot) {
195        if (config->enable_high) {
196            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
197        } else {
198            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
199        }
200    } else {
201        if (config->enable_high) {
202            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_LOW;
203        } else {
204            cfg.ena_gpio_flags |= GPIOF_OUT_INIT_HIGH;
205        }
206    }
207    if (config->gpio_is_open_drain)
208        cfg.ena_gpio_flags |= GPIOF_OPEN_DRAIN;
209
210    cfg.dev = &pdev->dev;
211    cfg.init_data = config->init_data;
212    cfg.driver_data = drvdata;
213    cfg.of_node = pdev->dev.of_node;
214
215    drvdata->dev = regulator_register(&drvdata->desc, &cfg);
216    if (IS_ERR(drvdata->dev)) {
217        ret = PTR_ERR(drvdata->dev);
218        dev_err(&pdev->dev, "Failed to register regulator: %d\n", ret);
219        goto err_input;
220    }
221
222    platform_set_drvdata(pdev, drvdata);
223
224    dev_dbg(&pdev->dev, "%s supplying %duV\n", drvdata->desc.name,
225        drvdata->microvolts);
226
227    return 0;
228
229err_input:
230    kfree(drvdata->desc.supply_name);
231err_name:
232    kfree(drvdata->desc.name);
233err:
234    return ret;
235}
236
237static int __devexit reg_fixed_voltage_remove(struct platform_device *pdev)
238{
239    struct fixed_voltage_data *drvdata = platform_get_drvdata(pdev);
240
241    regulator_unregister(drvdata->dev);
242    kfree(drvdata->desc.supply_name);
243    kfree(drvdata->desc.name);
244
245    return 0;
246}
247
248#if defined(CONFIG_OF)
249static const struct of_device_id fixed_of_match[] __devinitconst = {
250    { .compatible = "regulator-fixed", },
251    {},
252};
253MODULE_DEVICE_TABLE(of, fixed_of_match);
254#endif
255
256static struct platform_driver regulator_fixed_voltage_driver = {
257    .probe = reg_fixed_voltage_probe,
258    .remove = __devexit_p(reg_fixed_voltage_remove),
259    .driver = {
260        .name = "reg-fixed-voltage",
261        .owner = THIS_MODULE,
262        .of_match_table = of_match_ptr(fixed_of_match),
263    },
264};
265
266static int __init regulator_fixed_voltage_init(void)
267{
268    return platform_driver_register(&regulator_fixed_voltage_driver);
269}
270subsys_initcall(regulator_fixed_voltage_init);
271
272static void __exit regulator_fixed_voltage_exit(void)
273{
274    platform_driver_unregister(&regulator_fixed_voltage_driver);
275}
276module_exit(regulator_fixed_voltage_exit);
277
278MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
279MODULE_DESCRIPTION("Fixed voltage regulator");
280MODULE_LICENSE("GPL");
281MODULE_ALIAS("platform:reg-fixed-voltage");
282

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