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Linux/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, ""))
 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");
187 

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