userspace-consumer.c

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/*
 * userspace-consumer.c
 *
 * Copyright 2009 CompuLab, Ltd.
 *
 * Author: Mike Rapoport <[email protected]>
 *
 * Based of virtual consumer driver:
 *   Copyright 2008 Wolfson Microelectronics PLC.
 *   Author: Mark Brown <[email protected]>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 */

#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/userspace-consumer.h>
#include <linux/slab.h>

struct userspace_consumer_data {
    const char *name;

    struct mutex lock;
    bool enabled;

    int num_supplies;
    struct regulator_bulk_data *supplies;
};

static ssize_t reg_show_name(struct device *dev,
              struct device_attribute *attr, char *buf)
{
    struct userspace_consumer_data *data = dev_get_drvdata(dev);

    return sprintf(buf, "%s\n", data->name);
}

static ssize_t reg_show_state(struct device *dev,
              struct device_attribute *attr, char *buf)
{
    struct userspace_consumer_data *data = dev_get_drvdata(dev);

    if (data->enabled)
        return sprintf(buf, "enabled\n");

    return sprintf(buf, "disabled\n");
}

static ssize_t reg_set_state(struct device *dev, struct device_attribute *attr,
             const char *buf, size_t count)
{
    struct userspace_consumer_data *data = dev_get_drvdata(dev);
    bool enabled;
    int ret;

    /*
     * sysfs_streq() doesn't need the \n's, but we add them so the strings
     * will be shared with show_state(), above.
     */
    if (sysfs_streq(buf, "enabled\n") || sysfs_streq(buf, "1"))
        enabled = true;
    else if (sysfs_streq(buf, "disabled\n") || sysfs_streq(buf, "0"))
        enabled = false;
    else {
        dev_err(dev, "Configuring invalid mode\n");
        return count;
    }

    mutex_lock(&data->lock);
    if (enabled != data->enabled) {
        if (enabled)
            ret = regulator_bulk_enable(data->num_supplies,
                            data->supplies);
        else
            ret = regulator_bulk_disable(data->num_supplies,
                             data->supplies);

        if (ret == 0)
            data->enabled = enabled;
        else
            dev_err(dev, "Failed to configure state: %d\n", ret);
    }
    mutex_unlock(&data->lock);

    return count;
}

static DEVICE_ATTR(name, 0444, reg_show_name, NULL);
static DEVICE_ATTR(state, 0644, reg_show_state, reg_set_state);

static struct attribute *attributes[] = {
    &dev_attr_name.attr,
    &dev_attr_state.attr,
    NULL,
};

static const struct attribute_group attr_group = {
    .attrs  = attributes,
};

static int regulator_userspace_consumer_probe(struct platform_device *pdev)
{
    struct regulator_userspace_consumer_data *pdata;
    struct userspace_consumer_data *drvdata;
    int ret;

    pdata = pdev->dev.platform_data;
    if (!pdata)
        return -EINVAL;

    drvdata = devm_kzalloc(&pdev->dev,
                   sizeof(struct userspace_consumer_data),
                   GFP_KERNEL);
    if (drvdata == NULL)
        return -ENOMEM;

    drvdata->name = pdata->name;
    drvdata->num_supplies = pdata->num_supplies;
    drvdata->supplies = pdata->supplies;

    mutex_init(&drvdata->lock);

    ret = devm_regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
                      drvdata->supplies);
    if (ret) {
        dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
        return ret;
    }

    ret = sysfs_create_group(&pdev->dev.kobj, &attr_group);
    if (ret != 0)
        return ret;

    if (pdata->init_on) {
        ret = regulator_bulk_enable(drvdata->num_supplies,
                        drvdata->supplies);
        if (ret) {
            dev_err(&pdev->dev,
                "Failed to set initial state: %d\n", ret);
            goto err_enable;
        }
    }

    drvdata->enabled = pdata->init_on;
    platform_set_drvdata(pdev, drvdata);

    return 0;

err_enable:
    sysfs_remove_group(&pdev->dev.kobj, &attr_group);

    return ret;
}

static int regulator_userspace_consumer_remove(struct platform_device *pdev)
{
    struct userspace_consumer_data *data = platform_get_drvdata(pdev);

    sysfs_remove_group(&pdev->dev.kobj, &attr_group);

    if (data->enabled)
        regulator_bulk_disable(data->num_supplies, data->supplies);

    return 0;
}

static struct platform_driver regulator_userspace_consumer_driver = {
    .probe      = regulator_userspace_consumer_probe,
    .remove     = regulator_userspace_consumer_remove,
    .driver     = {
        .name       = "reg-userspace-consumer",
    },
};

module_platform_driver(regulator_userspace_consumer_driver);

MODULE_AUTHOR("Mike Rapoport <[email protected]>");
MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
MODULE_LICENSE("GPL");