linux/drivers/regulator/userspace-consumer.c
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   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
  27struct 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
  37static 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
  45static 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
  56static 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
  95static DEVICE_ATTR(name, 0444, reg_show_name, NULL);
  96static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);
  97
  98static struct attribute *attributes[] = {
  99        &dev_attr_name.attr,
 100        &dev_attr_state.attr,
 101        NULL,
 102};
 103
 104static const struct attribute_group attr_group = {
 105        .attrs  = attributes,
 106};
 107
 108static 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 = pdev->dev.platform_data;
 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
 156err_enable:
 157        sysfs_remove_group(&pdev->dev.kobj, &attr_group);
 158
 159        return ret;
 160}
 161
 162static 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
 174static 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
 182module_platform_driver(regulator_userspace_consumer_driver);
 183
 184MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
 185MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
 186MODULE_LICENSE("GPL");
 187
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