// SPDX-License-Identifier: GPL-2.0-only
/*
 * Kirkwood thermal sensor driver
 *
 * Copyright (C) 2012 Nobuhiro Iwamatsu <iwamatsu@nigauri.org>
 */
#include <linux/device.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/of.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/thermal.h>

#define KIRKWOOD_THERMAL_VALID_OFFSET   9
#define KIRKWOOD_THERMAL_VALID_MASK     0x1
#define KIRKWOOD_THERMAL_TEMP_OFFSET    10
#define KIRKWOOD_THERMAL_TEMP_MASK      0x1FF

/* Kirkwood Thermal Sensor Dev Structure */
struct kirkwood_thermal_priv {
        void __iomem *sensor;
};

static int kirkwood_get_temp(struct thermal_zone_device *thermal,
                          int *temp)
{
        unsigned long reg;
        struct kirkwood_thermal_priv *priv = thermal_zone_device_priv(thermal);

        reg = readl_relaxed(priv->sensor);

        /* Valid check */
        if (!((reg >> KIRKWOOD_THERMAL_VALID_OFFSET) &
            KIRKWOOD_THERMAL_VALID_MASK))
                return -EIO;

        /*
         * Calculate temperature. According to Marvell internal
         * documentation the formula for this is:
         * Celsius = (322-reg)/1.3625
         */
        reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &
                KIRKWOOD_THERMAL_TEMP_MASK;
        *temp = ((3220000000UL - (10000000UL * reg)) / 13625);

        return 0;
}

static const struct thermal_zone_device_ops ops = {
        .get_temp = kirkwood_get_temp,
};

static const struct of_device_id kirkwood_thermal_id_table[] = {
        { .compatible = "marvell,kirkwood-thermal" },
        {}
};

static int kirkwood_thermal_probe(struct platform_device *pdev)
{
        struct thermal_zone_device *thermal = NULL;
        struct kirkwood_thermal_priv *priv;
        int ret;

        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
        if (!priv)
                return -ENOMEM;

        priv->sensor = devm_platform_get_and_ioremap_resource(pdev, 0, NULL);
        if (IS_ERR(priv->sensor))
                return PTR_ERR(priv->sensor);

        thermal = thermal_tripless_zone_device_register("kirkwood_thermal",
                                                        priv, &ops, NULL);
        if (IS_ERR(thermal)) {
                dev_err(&pdev->dev,
                        "Failed to register thermal zone device\n");
                return PTR_ERR(thermal);
        }
        ret = thermal_zone_device_enable(thermal);
        if (ret) {
                thermal_zone_device_unregister(thermal);
                dev_err(&pdev->dev, "Failed to enable thermal zone device\n");
                return ret;
        }

        platform_set_drvdata(pdev, thermal);

        return 0;
}

static void kirkwood_thermal_exit(struct platform_device *pdev)
{
        struct thermal_zone_device *kirkwood_thermal =
                platform_get_drvdata(pdev);

        thermal_zone_device_unregister(kirkwood_thermal);
}

MODULE_DEVICE_TABLE(of, kirkwood_thermal_id_table);

static struct platform_driver kirkwood_thermal_driver = {
        .probe = kirkwood_thermal_probe,
        .remove = kirkwood_thermal_exit,
        .driver = {
                .name = "kirkwood_thermal",
                .of_match_table = kirkwood_thermal_id_table,
        },
};

module_platform_driver(kirkwood_thermal_driver);

MODULE_AUTHOR("Nobuhiro Iwamatsu <iwamatsu@nigauri.org>");
MODULE_DESCRIPTION("kirkwood thermal driver");
MODULE_LICENSE("GPL");