// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * 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>
 */

#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/module.h>
#include <linux/of.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;
        bool no_autoswitch;

        int num_supplies;
        struct regulator_bulk_data *supplies;
};

static ssize_t name_show(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 state_show(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 state_store(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_RO(name);
static DEVICE_ATTR_RW(state);

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

static umode_t attr_visible(struct kobject *kobj, struct attribute *attr, int idx)
{
        struct device *dev = kobj_to_dev(kobj);
        struct userspace_consumer_data *data = dev_get_drvdata(dev);

        /* If a name hasn't been set, don't bother with the attribute */
        if (attr == &dev_attr_name.attr && !data->name)
                return 0;

        return attr->mode;
}

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

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

        pdata = dev_get_platdata(&pdev->dev);
        if (!pdata) {
                if (!pdev->dev.of_node)
                        return -EINVAL;

                pdata = &tmpdata;
                memset(pdata, 0, sizeof(*pdata));

                pdata->no_autoswitch = true;
                pdata->num_supplies = 1;
                pdata->supplies = devm_kzalloc(&pdev->dev, sizeof(*pdata->supplies), GFP_KERNEL);
                if (!pdata->supplies)
                        return -ENOMEM;
                pdata->supplies[0].supply = "vout";
        }

        if (pdata->num_supplies < 1) {
                dev_err(&pdev->dev, "At least one supply required\n");
                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;
        drvdata->no_autoswitch = pdata->no_autoswitch;

        mutex_init(&drvdata->lock);

        ret = devm_regulator_bulk_get_exclusive(&pdev->dev, drvdata->num_supplies,
                                                drvdata->supplies);
        if (ret)
                return dev_err_probe(&pdev->dev, ret, "Failed to get supplies\n");

        platform_set_drvdata(pdev, drvdata);

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

        if (pdata->init_on && !pdata->no_autoswitch) {
                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;
                }
        }

        ret = regulator_is_enabled(pdata->supplies[0].consumer);
        if (ret < 0) {
                dev_err(&pdev->dev, "Failed to get regulator status\n");
                goto err_enable;
        }
        drvdata->enabled = !!ret;

        return 0;

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

        return ret;
}

static void 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 && !data->no_autoswitch)
                regulator_bulk_disable(data->num_supplies, data->supplies);
}

static const struct of_device_id regulator_userspace_consumer_of_match[] = {
        { .compatible = "regulator-output", },
        {},
};
MODULE_DEVICE_TABLE(of, regulator_userspace_consumer_of_match);

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

module_platform_driver(regulator_userspace_consumer_driver);

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