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 #include <linux/slab.h>
  25
  26 struct userspace_consumer_data {
  27         const char *name;
  28
  29         struct mutex lock;
  30         bool enabled;
  31
  32         int num_supplies;
  33         struct regulator_bulk_data *supplies;
  34 };
  35
  36 static ssize_t reg_show_name(struct device *dev,
  37                           struct device_attribute *attr, char *buf)
  38 {
  39         struct userspace_consumer_data *data = dev_get_drvdata(dev);
  40
  41         return sprintf(buf, "%s\n", data->name);
  42 }
  43
  44 static ssize_t reg_show_state(struct device *dev,
  45                           struct device_attribute *attr, char *buf)
  46 {
  47         struct userspace_consumer_data *data = dev_get_drvdata(dev);
  48
  49         if (data->enabled)
  50                 return sprintf(buf, "enabled\n");
  51
  52         return sprintf(buf, "disabled\n");
  53 }
  54
  55 static ssize_t reg_set_state(struct device *dev, struct device_attribute *attr,
  56                          const char *buf, size_t count)
  57 {
  58         struct userspace_consumer_data *data = dev_get_drvdata(dev);
  59         bool enabled;
  60         int ret;
  61
  62         /*
  63          * sysfs_streq() doesn't need the \n's, but we add them so the strings
  64          * will be shared with show_state(), above.
  65          */
  66         if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
  67                 enabled = true;
  68         else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
  69                 enabled = false;
  70         else {
  71                 dev_err(dev, "Configuring invalid mode\n");
  72                 return count;
  73         }
  74
  75         mutex_lock(&data->lock);
  76         if (enabled != data->enabled) {
  77                 if (enabled)
  78                         ret = regulator_bulk_enable(data->num_supplies,
  79                                                     data->supplies);
  80                 else
  81                         ret = regulator_bulk_disable(data->num_supplies,
  82                                                      data->supplies);
  83
  84                 if (ret == 0)
  85                         data->enabled = enabled;
  86                 else
  87                         dev_err(dev, "Failed to configure state: %d\n", ret);
  88         }
  89         mutex_unlock(&data->lock);
  90
  91         return count;
  92 }
  93
  94 static DEVICE_ATTR(name, 0444, reg_show_name, NULL);
  95 static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);
  96
  97 static struct attribute *attributes[] = {
  98         &dev_attr_name.attr,
  99         &dev_attr_state.attr,
 100         NULL,
 101 };
 102
 103 static const struct attribute_group attr_group = {
 104         .attrs  = attributes,
 105 };
 106
 107 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
 108 {
 109         struct regulator_userspace_consumer_data *pdata;
 110         struct userspace_consumer_data *drvdata;
 111         int ret;
 112
 113         pdata = pdev->dev.platform_data;
 114         if (!pdata)
 115                 return -EINVAL;
 116
 117         drvdata = kzalloc(sizeof(struct userspace_consumer_data), GFP_KERNEL);
 118         if (drvdata == NULL)
 119                 return -ENOMEM;
 120
 121         drvdata->name = pdata->name;
 122         drvdata->num_supplies = pdata->num_supplies;
 123         drvdata->supplies = pdata->supplies;
 124
 125         mutex_init(&drvdata->lock);
 126
 127         ret = regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
 128                                  drvdata->supplies);
 129         if (ret) {
 130                 dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
 131                 goto err_alloc_supplies;
 132         }
 133
 134         ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
 135         if (ret != 0)
 136                 goto err_create_attrs;
 137
 138         if (pdata->init_on) {
 139                 ret = regulator_bulk_enable(drvdata->num_supplies,
 140                                             drvdata->supplies);
 141                 if (ret) {
 142                         dev_err(&pdev->dev,
 143                                 "Failed to set initial state: %d\n", ret);
 144                         goto err_enable;
 145                 }
 146         }
 147
 148         drvdata->enabled = pdata->init_on;
 149         platform_set_drvdata(pdev, drvdata);
 150
 151         return 0;
 152
 153 err_enable:
 154         sysfs_remove_group(&pdev->dev.kobj, &attr_group);
 155
 156 err_create_attrs:
 157         regulator_bulk_free(drvdata->num_supplies, drvdata->supplies);
 158
 159 err_alloc_supplies:
 160         kfree(drvdata);
 161         return ret;
 162 }
 163
 164 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
 165 {
 166         struct userspace_consumer_data *data = platform_get_drvdata(pdev);
 167
 168         sysfs_remove_group(&pdev->dev.kobj, &attr_group);
 169
 170         if (data->enabled)
 171                 regulator_bulk_disable(data->num_supplies, data->supplies);
 172
 173         regulator_bulk_free(data->num_supplies, data->supplies);
 174         kfree(data);
 175
 176         return 0;
 177 }
 178
 179 static struct platform_driver regulator_userspace_consumer_driver = {
 180         .probe          = regulator_userspace_consumer_probe,
 181         .remove         = regulator_userspace_consumer_remove,
 182         .driver         = {
 183                 .name           = "reg-userspace-consumer",
 184         },
 185 };
 186
 187
 188 static int __init regulator_userspace_consumer_init(void)
 189 {
 190         return platform_driver_register(&regulator_userspace_consumer_driver);
 191 }
 192 module_init(regulator_userspace_consumer_init);
 193
 194 static void __exit regulator_userspace_consumer_exit(void)
 195 {
 196         platform_driver_unregister(&regulator_userspace_consumer_driver);
 197 }
 198 module_exit(regulator_userspace_consumer_exit);
 199
 200 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
 201 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
 202 MODULE_LICENSE("GPL");