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

#include <linux/errno.h>
#include <linux/gnss.h>
#include <linux/gpio/consumer.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 ubx_data {
        struct regulator *vcc;
};

static int ubx_set_active(struct gnss_serial *gserial)
{
        struct ubx_data *data = gnss_serial_get_drvdata(gserial);
        int ret;

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

        return 0;
}

static int ubx_set_standby(struct gnss_serial *gserial)
{
        struct ubx_data *data = gnss_serial_get_drvdata(gserial);
        int ret;

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

        return 0;
}

static int ubx_set_power(struct gnss_serial *gserial,
                                enum gnss_serial_pm_state state)
{
        switch (state) {
        case GNSS_SERIAL_ACTIVE:
                return ubx_set_active(gserial);
        case GNSS_SERIAL_OFF:
        case GNSS_SERIAL_STANDBY:
                return ubx_set_standby(gserial);
        }

        return -EINVAL;
}

static const struct gnss_serial_ops ubx_gserial_ops = {
        .set_power = ubx_set_power,
};

static int ubx_probe(struct serdev_device *serdev)
{
        struct gnss_serial *gserial;
        struct gpio_desc *safeboot;
        struct gpio_desc *reset;
        struct ubx_data *data;
        int ret;

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

        gserial->ops = &ubx_gserial_ops;

        gserial->gdev->type = GNSS_TYPE_UBX;

        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;
        }

        ret = devm_regulator_get_enable_optional(&serdev->dev, "v-bckp");
        if (ret < 0 && ret != -ENODEV)
                goto err_free_gserial;

        /* Deassert safeboot */
        safeboot = devm_gpiod_get_optional(&serdev->dev, "safeboot", GPIOD_OUT_LOW);
        if (IS_ERR(safeboot)) {
                ret = PTR_ERR(safeboot);
                goto err_free_gserial;
        }

        /* Deassert reset */
        reset = devm_gpiod_get_optional(&serdev->dev, "reset", GPIOD_OUT_LOW);
        if (IS_ERR(reset)) {
                ret = PTR_ERR(reset);
                goto err_free_gserial;
        }

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

        return 0;

err_free_gserial:
        gnss_serial_free(gserial);

        return ret;
}

static void ubx_remove(struct serdev_device *serdev)
{
        struct gnss_serial *gserial = serdev_device_get_drvdata(serdev);

        gnss_serial_deregister(gserial);
        gnss_serial_free(gserial);
}

#ifdef CONFIG_OF
static const struct of_device_id ubx_of_match[] = {
        { .compatible = "u-blox,neo-6m" },
        { .compatible = "u-blox,neo-8" },
        { .compatible = "u-blox,neo-m8" },
        {},
};
MODULE_DEVICE_TABLE(of, ubx_of_match);
#endif

static struct serdev_device_driver ubx_driver = {
        .driver = {
                .name           = "gnss-ubx",
                .of_match_table = of_match_ptr(ubx_of_match),
                .pm             = &gnss_serial_pm_ops,
        },
        .probe  = ubx_probe,
        .remove = ubx_remove,
};
module_serdev_device_driver(ubx_driver);

MODULE_AUTHOR("Johan Hovold <johan@kernel.org>");
MODULE_DESCRIPTION("u-blox GNSS receiver driver");
MODULE_LICENSE("GPL v2");