regulator: add userspace-consumer driver
[linux-2.6.git] / drivers / regulator / userspace-consumer.c
1 /*
2  * userspace-consumer.c
3  *
4  * Copyright 2009 CompuLab, Ltd.
5  *
6  * Author: Mike Rapoport <mike@compulab.co.il>
7  *
8  * Based of virtual consumer driver:
9  *   Copyright 2008 Wolfson Microelectronics PLC.
10  *   Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
11  *
12  * This program is free software; you can redistribute it and/or
13  * modify it under the terms of the GNU General Public License as
14  * published by the Free Software Foundation; either version 2 of the
15  * License, or (at your option) any later version.
16  *
17  */
18
19 #include <linux/err.h>
20 #include <linux/mutex.h>
21 #include <linux/platform_device.h>
22 #include <linux/regulator/consumer.h>
23 #include <linux/regulator/userspace-consumer.h>
24
25 struct userspace_consumer_data {
26         const char *name;
27
28         struct mutex lock;
29         bool enabled;
30
31         int num_supplies;
32         struct regulator_bulk_data *supplies;
33 };
34
35 static ssize_t show_name(struct device *dev,
36                           struct device_attribute *attr, char *buf)
37 {
38         struct userspace_consumer_data *data = dev_get_drvdata(dev);
39
40         return sprintf(buf, "%s\n", data->name);
41 }
42
43 static ssize_t show_state(struct device *dev,
44                           struct device_attribute *attr, char *buf)
45 {
46         struct userspace_consumer_data *data = dev_get_drvdata(dev);
47
48         if (data->enabled)
49                 return sprintf(buf, "enabled\n");
50
51         return sprintf(buf, "disabled\n");
52 }
53
54 static ssize_t set_state(struct device *dev, struct device_attribute *attr,
55                          const char *buf, size_t count)
56 {
57         struct userspace_consumer_data *data = dev_get_drvdata(dev);
58         bool enabled;
59         int ret;
60
61         /*
62          * sysfs_streq() doesn't need the \n's, but we add them so the strings
63          * will be shared with show_state(), above.
64          */
65         if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
66                 enabled = true;
67         else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
68                 enabled = false;
69         else {
70                 dev_err(dev, "Configuring invalid mode\n");
71                 return count;
72         }
73
74         mutex_lock(&data->lock);
75         if (enabled != data->enabled) {
76                 if (enabled)
77                         ret = regulator_bulk_enable(data->num_supplies,
78                                                     data->supplies);
79                 else
80                         ret = regulator_bulk_disable(data->num_supplies,
81                                                      data->supplies);
82
83                 if (ret == 0)
84                         data->enabled = enabled;
85                 else
86                         dev_err(dev, "Failed to configure state: %d\n", ret);
87         }
88         mutex_unlock(&data->lock);
89
90         return count;
91 }
92
93 static DEVICE_ATTR(name, 0444, show_name, NULL);
94 static DEVICE_ATTR(state, 0644, show_state, set_state);
95
96 static struct device_attribute *attributes[] = {
97         &dev_attr_name,
98         &dev_attr_state,
99 };
100
101 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
102 {
103         struct regulator_userspace_consumer_data *pdata;
104         struct userspace_consumer_data *drvdata;
105         int ret, i;
106
107         pdata = pdev->dev.platform_data;
108         if (!pdata)
109                 return -EINVAL;
110
111         drvdata = kzalloc(sizeof(struct userspace_consumer_data), GFP_KERNEL);
112         if (drvdata == NULL)
113                 return -ENOMEM;
114
115         drvdata->name = pdata->name;
116         drvdata->num_supplies = pdata->num_supplies;
117         drvdata->supplies = pdata->supplies;
118
119         mutex_init(&drvdata->lock);
120
121         ret = regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
122                                  drvdata->supplies);
123         if (ret) {
124                 dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
125                 goto err_alloc_supplies;
126         }
127
128         for (i = 0; i < ARRAY_SIZE(attributes); i++) {
129                 ret = device_create_file(&pdev->dev, attributes[i]);
130                 if (ret != 0)
131                         goto err_create_attrs;
132         }
133
134         if (pdata->init_on)
135                 ret = regulator_bulk_enable(drvdata->num_supplies,
136                                             drvdata->supplies);
137
138         drvdata->enabled = pdata->init_on;
139
140         if (ret) {
141                 dev_err(&pdev->dev, "Failed to set initial state: %d\n", ret);
142                 goto err_create_attrs;
143         }
144
145         platform_set_drvdata(pdev, drvdata);
146
147         return 0;
148
149 err_create_attrs:
150         for (i = 0; i < ARRAY_SIZE(attributes); i++)
151                 device_remove_file(&pdev->dev, attributes[i]);
152
153         regulator_bulk_free(drvdata->num_supplies, drvdata->supplies);
154
155 err_alloc_supplies:
156         kfree(drvdata);
157         return ret;
158 }
159
160 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
161 {
162         struct userspace_consumer_data *data = platform_get_drvdata(pdev);
163         int i;
164
165         for (i = 0; i < ARRAY_SIZE(attributes); i++)
166                 device_remove_file(&pdev->dev, attributes[i]);
167
168         if (data->enabled)
169                 regulator_bulk_disable(data->num_supplies, data->supplies);
170
171         regulator_bulk_free(data->num_supplies, data->supplies);
172         kfree(data);
173
174         return 0;
175 }
176
177 static struct platform_driver regulator_userspace_consumer_driver = {
178         .probe          = regulator_userspace_consumer_probe,
179         .remove         = regulator_userspace_consumer_remove,
180         .driver         = {
181                 .name           = "reg-userspace-consumer",
182         },
183 };
184
185
186 static int __init regulator_userspace_consumer_init(void)
187 {
188         return platform_driver_register(&regulator_userspace_consumer_driver);
189 }
190 module_init(regulator_userspace_consumer_init);
191
192 static void __exit regulator_userspace_consumer_exit(void)
193 {
194         platform_driver_unregister(&regulator_userspace_consumer_driver);
195 }
196 module_exit(regulator_userspace_consumer_exit);
197
198 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
199 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
200 MODULE_LICENSE("GPL");