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 reg_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 reg_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 reg_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, reg_show_name, NULL);
  94 static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);
  95
  96 static struct attribute *attributes[] = {
  97         &dev_attr_name.attr,
  98         &dev_attr_state.attr,
  99         NULL,
 100 };
 101
 102 static const struct attribute_group attr_group = {
 103         .attrs  = attributes,
 104 };
 105
 106 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
 107 {
 108         struct regulator_userspace_consumer_data *pdata;
 109         struct userspace_consumer_data *drvdata;
 110         int ret;
 111
 112         pdata = pdev->dev.platform_data;
 113         if (!pdata)
 114                 return -EINVAL;
 115
 116         drvdata = kzalloc(sizeof(struct userspace_consumer_data), GFP_KERNEL);
 117         if (drvdata == NULL)
 118                 return -ENOMEM;
 119
 120         drvdata->name = pdata->name;
 121         drvdata->num_supplies = pdata->num_supplies;
 122         drvdata->supplies = pdata->supplies;
 123
 124         mutex_init(&drvdata->lock);
 125
 126         ret = regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
 127                                  drvdata->supplies);
 128         if (ret) {
 129                 dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
 130                 goto err_alloc_supplies;
 131         }
 132
 133         ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
 134         if (ret != 0)
 135                 goto err_create_attrs;
 136
 137         if (pdata->init_on) {
 138                 ret = regulator_bulk_enable(drvdata->num_supplies,
 139                                             drvdata->supplies);
 140                 if (ret) {
 141                         dev_err(&pdev->dev,
 142                                 "Failed to set initial state: %d\n", ret);
 143                         goto err_enable;
 144                 }
 145         }
 146
 147         drvdata->enabled = pdata->init_on;
 148         platform_set_drvdata(pdev, drvdata);
 149
 150         return 0;
 151
 152 err_enable:
 153         sysfs_remove_group(&pdev->dev.kobj, &attr_group);
 154
 155 err_create_attrs:
 156         regulator_bulk_free(drvdata->num_supplies, drvdata->supplies);
 157
 158 err_alloc_supplies:
 159         kfree(drvdata);
 160         return ret;
 161 }
 162
 163 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
 164 {
 165         struct userspace_consumer_data *data = platform_get_drvdata(pdev);
 166
 167         sysfs_remove_group(&pdev->dev.kobj, &attr_group);
 168
 169         if (data->enabled)
 170                 regulator_bulk_disable(data->num_supplies, data->supplies);
 171
 172         regulator_bulk_free(data->num_supplies, data->supplies);
 173         kfree(data);
 174
 175         return 0;
 176 }
 177
 178 static struct platform_driver regulator_userspace_consumer_driver = {
 179         .probe          = regulator_userspace_consumer_probe,
 180         .remove         = regulator_userspace_consumer_remove,
 181         .driver         = {
 182                 .name           = "reg-userspace-consumer",
 183         },
 184 };
 185
 186
 187 static int __init regulator_userspace_consumer_init(void)
 188 {
 189         return platform_driver_register(&regulator_userspace_consumer_driver);
 190 }
 191 module_init(regulator_userspace_consumer_init);
 192
 193 static void __exit regulator_userspace_consumer_exit(void)
 194 {
 195         platform_driver_unregister(&regulator_userspace_consumer_driver);
 196 }
 197 module_exit(regulator_userspace_consumer_exit);
 198
 199 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
 200 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
 201 MODULE_LICENSE("GPL");