// SPDX-License-Identifier: GPL-2.0
/*
 * Renesas RZ/G3S TSU Thermal Sensor Driver
 *
 * Copyright (C) 2024 Renesas Electronics Corporation
 */

#include <linux/bitfield.h>
#include <linux/delay.h>
#include <linux/iio/consumer.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/thermal.h>
#include <linux/units.h>

#include "../thermal_hwmon.h"

#define TSU_SM                  0x0
#define TSU_SM_EN               BIT(0)
#define TSU_SM_OE               BIT(1)
#define OTPTSUTRIM_REG(n)       (0x18 + (n) * 0x4)
#define OTPTSUTRIM_EN_MASK      BIT(31)
#define OTPTSUTRIM_MASK         GENMASK(11, 0)

#define TSU_READ_STEPS          8

/* Default calibration values, if FUSE values are missing. */
#define SW_CALIB0_VAL           1297
#define SW_CALIB1_VAL           751

#define MCELSIUS(temp)          ((temp) * MILLIDEGREE_PER_DEGREE)

/**
 * struct rzg3s_thermal_priv - RZ/G3S thermal private data structure
 * @base: TSU base address
 * @dev: device pointer
 * @tz: thermal zone pointer
 * @rstc: reset control
 * @channel: IIO channel to read the TSU
 * @mode: current device mode
 * @calib0: calibration value
 * @calib1: calibration value
 */
struct rzg3s_thermal_priv {
        void __iomem *base;
        struct device *dev;
        struct thermal_zone_device *tz;
        struct reset_control *rstc;
        struct iio_channel *channel;
        enum thermal_device_mode mode;
        u16 calib0;
        u16 calib1;
};

static int rzg3s_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
{
        struct rzg3s_thermal_priv *priv = thermal_zone_device_priv(tz);
        int ts_code_ave = 0;

        if (priv->mode != THERMAL_DEVICE_ENABLED)
                return -EAGAIN;

        for (u8 i = 0; i < TSU_READ_STEPS; i++) {
                int ret, val;

                ret = iio_read_channel_raw(priv->channel, &val);
                if (ret < 0)
                        return ret;

                ts_code_ave += val;
                /*
                 * According to the HW manual (Rev.1.10, section 40.4.4 Procedure for Measuring
                 * the Temperature) we need to wait here at leat 3us.
                 */
                usleep_range(5, 10);
        }

        ts_code_ave = DIV_ROUND_CLOSEST(MCELSIUS(ts_code_ave), TSU_READ_STEPS);

        /*
         * According to the HW manual (Rev.1.10, section 40.4.4 Procedure for Measuring the
         * Temperature) the computation formula is as follows:
         *
         * Tj = (ts_code_ave - priv->calib1) * 165 / (priv->calib0 - priv->calib1) - 40
         *
         * Convert everything to milli Celsius before applying the formula to avoid
         * losing precision.
         */

        *temp = div_s64((s64)(ts_code_ave - MCELSIUS(priv->calib1)) * MCELSIUS(165),
                        MCELSIUS(priv->calib0 - priv->calib1)) - MCELSIUS(40);

        /* Report it in milli degrees Celsius and round it up to 0.5 degrees Celsius. */
        *temp = roundup(*temp, 500);

        return 0;
}

static void rzg3s_thermal_set_mode(struct rzg3s_thermal_priv *priv,
                                   enum thermal_device_mode mode)
{
        struct device *dev = priv->dev;
        int ret;

        ret = pm_runtime_resume_and_get(dev);
        if (ret)
                return;

        if (mode == THERMAL_DEVICE_DISABLED) {
                writel(0, priv->base + TSU_SM);
        } else {
                writel(TSU_SM_EN, priv->base + TSU_SM);
                /*
                 * According to the HW manual (Rev.1.10, section 40.4.1 Procedure for
                 * Starting the TSU) we need to wait here 30us or more.
                 */
                usleep_range(30, 40);

                writel(TSU_SM_OE | TSU_SM_EN, priv->base + TSU_SM);
                /*
                 * According to the HW manual (Rev.1.10, section 40.4.1 Procedure for
                 * Starting the TSU) we need to wait here 50us or more.
                 */
                usleep_range(50, 60);
        }

        pm_runtime_put_autosuspend(dev);
}

static int rzg3s_thermal_change_mode(struct thermal_zone_device *tz,
                                     enum thermal_device_mode mode)
{
        struct rzg3s_thermal_priv *priv = thermal_zone_device_priv(tz);

        if (priv->mode == mode)
                return 0;

        rzg3s_thermal_set_mode(priv, mode);
        priv->mode = mode;

        return 0;
}

static const struct thermal_zone_device_ops rzg3s_tz_of_ops = {
        .get_temp = rzg3s_thermal_get_temp,
        .change_mode = rzg3s_thermal_change_mode,
};

static int rzg3s_thermal_read_calib(struct rzg3s_thermal_priv *priv)
{
        struct device *dev = priv->dev;
        u32 val;
        int ret;

        ret = pm_runtime_resume_and_get(dev);
        if (ret)
                return ret;

        val = readl(priv->base + OTPTSUTRIM_REG(0));
        if (val & OTPTSUTRIM_EN_MASK)
                priv->calib0 = FIELD_GET(OTPTSUTRIM_MASK, val);
        else
                priv->calib0 = SW_CALIB0_VAL;

        val = readl(priv->base + OTPTSUTRIM_REG(1));
        if (val & OTPTSUTRIM_EN_MASK)
                priv->calib1 = FIELD_GET(OTPTSUTRIM_MASK, val);
        else
                priv->calib1 = SW_CALIB1_VAL;

        pm_runtime_put_autosuspend(dev);

        return 0;
}

static int rzg3s_thermal_probe(struct platform_device *pdev)
{
        struct rzg3s_thermal_priv *priv;
        struct device *dev = &pdev->dev;
        int ret;

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

        priv->base = devm_platform_ioremap_resource(pdev, 0);
        if (IS_ERR(priv->base))
                return PTR_ERR(priv->base);

        priv->channel = devm_iio_channel_get(dev, "tsu");
        if (IS_ERR(priv->channel))
                return dev_err_probe(dev, PTR_ERR(priv->channel), "Failed to get IIO channel!\n");

        priv->rstc = devm_reset_control_get_exclusive_deasserted(dev, NULL);
        if (IS_ERR(priv->rstc))
                return dev_err_probe(dev, PTR_ERR(priv->rstc), "Failed to get reset!\n");

        priv->dev = dev;
        priv->mode = THERMAL_DEVICE_DISABLED;
        platform_set_drvdata(pdev, priv);

        pm_runtime_set_autosuspend_delay(dev, 300);
        pm_runtime_use_autosuspend(dev);
        ret = devm_pm_runtime_enable(dev);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to enable runtime PM!\n");

        ret = rzg3s_thermal_read_calib(priv);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to read calibration data!\n");

        priv->tz = devm_thermal_of_zone_register(dev, 0, priv, &rzg3s_tz_of_ops);
        if (IS_ERR(priv->tz))
                return dev_err_probe(dev, PTR_ERR(priv->tz), "Failed to register thermal zone!\n");

        ret = devm_thermal_add_hwmon_sysfs(dev, priv->tz);
        if (ret)
                return dev_err_probe(dev, ret, "Failed to add hwmon sysfs!\n");

        return 0;
}

static int rzg3s_thermal_suspend(struct device *dev)
{
        struct rzg3s_thermal_priv *priv = dev_get_drvdata(dev);

        rzg3s_thermal_set_mode(priv, THERMAL_DEVICE_DISABLED);

        return reset_control_assert(priv->rstc);
}

static int rzg3s_thermal_resume(struct device *dev)
{
        struct rzg3s_thermal_priv *priv = dev_get_drvdata(dev);
        int ret;

        ret = reset_control_deassert(priv->rstc);
        if (ret)
                return ret;

        if (priv->mode != THERMAL_DEVICE_DISABLED)
                rzg3s_thermal_set_mode(priv, priv->mode);

        return 0;
}

static const struct dev_pm_ops rzg3s_thermal_pm_ops = {
        SYSTEM_SLEEP_PM_OPS(rzg3s_thermal_suspend, rzg3s_thermal_resume)
};

static const struct of_device_id rzg3s_thermal_dt_ids[] = {
        { .compatible = "renesas,r9a08g045-tsu" },
        { /* sentinel */ }
};
MODULE_DEVICE_TABLE(of, rzg3s_thermal_dt_ids);

static struct platform_driver rzg3s_thermal_driver = {
        .driver = {
                .name = "rzg3s-thermal",
                .of_match_table = rzg3s_thermal_dt_ids,
                .pm = pm_ptr(&rzg3s_thermal_pm_ops),
        },
        .probe = rzg3s_thermal_probe,
};
module_platform_driver(rzg3s_thermal_driver);

MODULE_DESCRIPTION("Renesas RZ/G3S Thermal Sensor Unit Driver");
MODULE_AUTHOR("Claudiu Beznea <claudiu.beznea.uj@bp.renesas.com>");
MODULE_LICENSE("GPL");