/*
 * userspace-consumer.c
 *
 * Copyright 2009 CompuLab, Ltd.
 *
 * Author: Mike Rapoport <mike@compulab.co.il>
 *
 * Based of virtual consumer driver:
 *   Copyright 2008 Wolfson Microelectronics PLC.
 *   Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
 *
 * 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/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 = kzalloc(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 = regulator_bulk_get(&pdev->dev, drvdata->num_supplies,
                                 drvdata->supplies);
        if (ret) {
                dev_err(&pdev->dev, "Failed to get supplies: %d\n", ret);
                goto err_alloc_supplies;
        }

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

        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);

err_create_attrs:
        regulator_bulk_free(drvdata->num_supplies, drvdata->supplies);

err_alloc_supplies:
        kfree(drvdata);
        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);

        regulator_bulk_free(data->num_supplies, data->supplies);
        kfree(data);

        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",
        },
};


static int __init regulator_userspace_consumer_init(void)
{
        return platform_driver_register(&regulator_userspace_consumer_driver);
}
module_init(regulator_userspace_consumer_init);

static void __exit regulator_userspace_consumer_exit(void)
{
        platform_driver_unregister(&regulator_userspace_consumer_driver);
}
module_exit(regulator_userspace_consumer_exit);

MODULE_AUTHOR("Mike Rapoport <mike@compulab.co.il>");
MODULE_DESCRIPTION("Userspace consumer for voltage and current regulators");
MODULE_LICENSE("GPL");