drivers/regulator/userspace-consumer.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * userspace-consumer.c
   4  *
   5  * Copyright 2009 CompuLab, Ltd.
   6  *
   7  * Author: Mike Rapoport <mike@compulab.co.il>
   8  *
   9  * Based of virtual consumer driver:
  10  *   Copyright 2008 Wolfson Microelectronics PLC.
  11  *   Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  12  */
  13
  14 #include <linux/err.h>
  15 #include <linux/mutex.h>
  16 #include <linux/module.h>
  17 #include <linux/platform_device.h>
  18 #include <linux/regulator/consumer.h>
  19 #include <linux/regulator/userspace-consumer.h>
  20 #include <linux/slab.h>
  21
  22 struct userspace_consumer_data {
  23         const char *name;
  24
  25         struct mutex lock;
  26         bool enabled;
  27
  28         int num_supplies;
  29         struct regulator_bulk_data *supplies;
  30 };
  31
  32 static ssize_t reg_show_name(struct device *dev,
  33                           struct device_attribute *attr, char *buf)
  34 {
  35         struct userspace_consumer_data *data = dev_get_drvdata(dev);
  36
  37         return sprintf(buf, "%s\n", data->name);
  38 }
  39
  40 static ssize_t reg_show_state(struct device *dev,
  41                           struct device_attribute *attr, char *buf)
  42 {
  43         struct userspace_consumer_data *data = dev_get_drvdata(dev);
  44
  45         if (data->enabled)
  46                 return sprintf(buf, "enabled\n");
  47
  48         return sprintf(buf, "disabled\n");
  49 }
  50
  51 static ssize_t reg_set_state(struct device *dev, struct device_attribute *attr,
  52                          const char *buf, size_t count)
  53 {
  54         struct userspace_consumer_data *data = dev_get_drvdata(dev);
  55         bool enabled;
  56         int ret;
  57
  58         /*
  59          * sysfs_streq() doesn't need the \n's, but we add them so the strings
  60          * will be shared with show_state(), above.
  61          */
  62         if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
  63                 enabled = true;
  64         else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
  65                 enabled = false;
  66         else {
  67                 dev_err(dev, "Configuring invalid mode\n");
  68                 return count;
  69         }
  70
  71         mutex_lock(&data->lock);
  72         if (enabled != data->enabled) {
  73                 if (enabled)
  74                         ret = regulator_bulk_enable(data->num_supplies,
  75                                                     data->supplies);
  76                 else
  77                         ret = regulator_bulk_disable(data->num_supplies,
  78                                                      data->supplies);
  79
  80                 if (ret == 0)
  81                         data->enabled = enabled;
  82                 else
  83                         dev_err(dev, "Failed to configure state: %d\n", ret);
  84         }
  85         mutex_unlock(&data->lock);
  86
  87         return count;
  88 }
  89
  90 static DEVICE_ATTR(name, 0444, reg_show_name, NULL);
  91 static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);
  92
  93 static struct attribute *attributes[] = {
  94         &dev_attr_name.attr,
  95         &dev_attr_state.attr,
  96         NULL,
  97 };
  98
  99 static const struct attribute_group attr_group = {
 100         .attrs  = attributes,
 101 };
 102
 103 static int regulator_userspace_consumer_probe(struct platform_device *pdev)
 104 {
 105         struct regulator_userspace_consumer_data *pdata;
 106         struct userspace_consumer_data *drvdata;
 107         int ret;
 108
 109         pdata = dev_get_platdata(&pdev->dev);
 110         if (!pdata)
 111                 return -EINVAL;
 112
 113         drvdata = devm_kzalloc(&pdev->dev,
 114                                sizeof(struct userspace_consumer_data),
 115                                GFP_KERNEL);
 116         if (drvdata == NULL)
 117                 return -ENOMEM;
 118
 119         drvdata->name = pdata->name;
 120         drvdata->num_supplies = pdata->num_supplies;
 121         drvdata->supplies = pdata->supplies;
 122
 123         mutex_init(&drvdata->lock);
 124
 125         ret = devm_regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
 126                                       drvdata->supplies);
 127         if (ret) {
 128                 dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
 129                 return ret;
 130         }
 131
 132         ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
 133         if (ret != 0)
 134                 return ret;
 135
 136         if (pdata->init_on) {
 137                 ret = regulator_bulk_enable(drvdata->num_supplies,
 138                                             drvdata->supplies);
 139                 if (ret) {
 140                         dev_err(&pdev->dev,
 141                                 "Failed to set initial state: %d\n", ret);
 142                         goto err_enable;
 143                 }
 144         }
 145
 146         drvdata->enabled = pdata->init_on;
 147         platform_set_drvdata(pdev, drvdata);
 148
 149         return 0;
 150
 151 err_enable:
 152         sysfs_remove_group(&pdev->dev.kobj, &attr_group);
 153
 154         return ret;
 155 }
 156
 157 static int regulator_userspace_consumer_remove(struct platform_device *pdev)
 158 {
 159         struct userspace_consumer_data *data = platform_get_drvdata(pdev);
 160
 161         sysfs_remove_group(&pdev->dev.kobj, &attr_group);
 162
 163         if (data->enabled)
 164                 regulator_bulk_disable(data->num_supplies, data->supplies);
 165
 166         return 0;
 167 }
 168
 169 static struct platform_driver regulator_userspace_consumer_driver = {
 170         .probe          = regulator_userspace_consumer_probe,
 171         .remove         = regulator_userspace_consumer_remove,
 172         .driver         = {
 173                 .name           = "reg-userspace-consumer",
 174         },
 175 };
 176
 177 module_platform_driver(regulator_userspace_consumer_driver);
 178
 179 MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
 180 MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
 181 MODULE_LICENSE("GPL");