// SPDX-License-Identifier: GPL-2.0
/*
 * Mediatek GNSS receiver driver
 *
 * Copyright (C) 2018 Johan Hovold <johan@kernel.org>
 */

#include <linux/errno.h>
#include <linux/gnss.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/regulator/consumer.h>
#include <linux/serdev.h>

#include "serial.h"

struct mtk_data {
        struct regulator *vbackup;
        struct regulator *vcc;
};

static int mtk_set_active(struct gnss_serial *gserial)
{
        struct mtk_data *data = gnss_serial_get_drvdata(gserial);
        int ret;

        ret = regulator_enable(data->vcc);
        if (ret)
                return ret;

        return 0;
}

static int mtk_set_standby(struct gnss_serial *gserial)
{
        struct mtk_data *data = gnss_serial_get_drvdata(gserial);
        int ret;

        ret = regulator_disable(data->vcc);
        if (ret)
                return ret;

        return 0;
}

static int mtk_set_power(struct gnss_serial *gserial,
                         enum gnss_serial_pm_state state)
{
        switch (state) {
        case GNSS_SERIAL_ACTIVE:
                return mtk_set_active(gserial);
        case GNSS_SERIAL_OFF:
        case GNSS_SERIAL_STANDBY:
                return mtk_set_standby(gserial);
        }

        return -EINVAL;
}

static const struct gnss_serial_ops mtk_gserial_ops = {
        .set_power = mtk_set_power,
};

static int mtk_probe(struct serdev_device *serdev)
{
        struct gnss_serial *gserial;
        struct mtk_data *data;
        int ret;

        gserial = gnss_serial_allocate(serdev, sizeof(*data));
        if (IS_ERR(gserial)) {
                ret = PTR_ERR(gserial);
                return ret;
        }

        gserial->ops = &mtk_gserial_ops;

        gserial->gdev->type = GNSS_TYPE_MTK;

        data = gnss_serial_get_drvdata(gserial);

        data->vcc = devm_regulator_get(&serdev->dev, "vcc");
        if (IS_ERR(data->vcc)) {
                ret = PTR_ERR(data->vcc);
                goto err_free_gserial;
        }

        data->vbackup = devm_regulator_get_optional(&serdev->dev, "vbackup");
        if (IS_ERR(data->vbackup)) {
                ret = PTR_ERR(data->vbackup);
                if (ret == -ENODEV)
                        data->vbackup = NULL;
                else
                        goto err_free_gserial;
        }

        if (data->vbackup) {
                ret = regulator_enable(data->vbackup);
                if (ret)
                        goto err_free_gserial;
        }

        ret = gnss_serial_register(gserial);
        if (ret)
                goto err_disable_vbackup;

        return 0;

err_disable_vbackup:
        if (data->vbackup)
                regulator_disable(data->vbackup);
err_free_gserial:
        gnss_serial_free(gserial);

        return ret;
}

static void mtk_remove(struct serdev_device *serdev)
{
        struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);
        struct mtk_data *data = gnss_serial_get_drvdata(gserial);

        gnss_serial_deregister(gserial);
        if (data->vbackup)
                regulator_disable(data->vbackup);
        gnss_serial_free(gserial);
}

#ifdef CONFIG_OF
static const struct of_device_id mtk_of_match[] = {
        { .compatible = "globaltop,pa6h" },
        {},
};
MODULE_DEVICE_TABLE(of, mtk_of_match);
#endif

static struct serdev_device_driver mtk_driver = {
        .driver = {
                .name           = "gnss-mtk",
                .of_match_table = of_match_ptr(mtk_of_match),
                .pm             = &gnss_serial_pm_ops,
        },
        .probe  = mtk_probe,
        .remove = mtk_remove,
};
module_serdev_device_driver(mtk_driver);

MODULE_AUTHOR("Loys Ollivier <lollivier@baylibre.com>");
MODULE_DESCRIPTION("Mediatek GNSS receiver driver");
MODULE_LICENSE("GPL v2");