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 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");