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