// SPDX-License-Identifier: GPL-2.0
/*
 *  R-Car THS/TSC thermal sensor driver
 *
 * Copyright (C) 2012 Renesas Solutions Corp.
 * Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
 */
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/reboot.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/thermal.h>

#include "thermal_hwmon.h"

#define IDLE_INTERVAL   5000

#define COMMON_STR      0x00
#define COMMON_ENR      0x04
#define COMMON_INTMSK   0x0c

#define REG_POSNEG      0x20
#define REG_FILONOFF    0x28
#define REG_THSCR       0x2c
#define REG_THSSR       0x30
#define REG_INTCTRL     0x34

/* THSCR */
#define CPCTL   (1 << 12)

/* THSSR */
#define CTEMP   0x3f

struct rcar_thermal_common {
        void __iomem *base;
        struct device *dev;
        struct list_head head;
        spinlock_t lock;
};

struct rcar_thermal_chip {
        unsigned int use_of_thermal : 1;
        unsigned int has_filonoff : 1;
        unsigned int irq_per_ch : 1;
        unsigned int needs_suspend_resume : 1;
        unsigned int nirqs;
};

static const struct rcar_thermal_chip rcar_thermal = {
        .use_of_thermal = 0,
        .has_filonoff = 1,
        .irq_per_ch = 0,
        .needs_suspend_resume = 0,
        .nirqs = 1,
};

static const struct rcar_thermal_chip rcar_gen2_thermal = {
        .use_of_thermal = 1,
        .has_filonoff = 1,
        .irq_per_ch = 0,
        .needs_suspend_resume = 0,
        .nirqs = 1,
};

static const struct rcar_thermal_chip rcar_gen3_thermal = {
        .use_of_thermal = 1,
        .has_filonoff = 0,
        .irq_per_ch = 1,
        .needs_suspend_resume = 1,
        /*
         * The Gen3 chip has 3 interrupts, but this driver uses only 2
         * interrupts to detect a temperature change, rise or fall.
         */
        .nirqs = 2,
};

struct rcar_thermal_priv {
        void __iomem *base;
        struct rcar_thermal_common *common;
        struct thermal_zone_device *zone;
        const struct rcar_thermal_chip *chip;
        struct delayed_work work;
        struct mutex lock;
        struct list_head list;
        int id;
        u32 ctemp;
};

#define rcar_thermal_for_each_priv(pos, common) \
        list_for_each_entry(pos, &common->head, list)

#define MCELSIUS(temp)                  ((temp) * 1000)
#define rcar_zone_to_priv(zone)         ((zone)->devdata)
#define rcar_priv_to_dev(priv)          ((priv)->common->dev)
#define rcar_has_irq_support(priv)      ((priv)->common->base)
#define rcar_id_to_shift(priv)          ((priv)->id * 8)

static const struct of_device_id rcar_thermal_dt_ids[] = {
        {
                .compatible = "renesas,rcar-thermal",
                .data = &rcar_thermal,
        },
        {
                .compatible = "renesas,rcar-gen2-thermal",
                 .data = &rcar_gen2_thermal,
        },
        {
                .compatible = "renesas,thermal-r8a77995",
                .data = &rcar_gen3_thermal,
        },
        {},
};
MODULE_DEVICE_TABLE(of, rcar_thermal_dt_ids);

/*
 *              basic functions
 */
#define rcar_thermal_common_read(c, r) \
        _rcar_thermal_common_read(c, COMMON_ ##r)
static u32 _rcar_thermal_common_read(struct rcar_thermal_common *common,
                                     u32 reg)
{
        return ioread32(common->base + reg);
}

#define rcar_thermal_common_write(c, r, d) \
        _rcar_thermal_common_write(c, COMMON_ ##r, d)
static void _rcar_thermal_common_write(struct rcar_thermal_common *common,
                                       u32 reg, u32 data)
{
        iowrite32(data, common->base + reg);
}

#define rcar_thermal_common_bset(c, r, m, d) \
        _rcar_thermal_common_bset(c, COMMON_ ##r, m, d)
static void _rcar_thermal_common_bset(struct rcar_thermal_common *common,
                                      u32 reg, u32 mask, u32 data)
{
        u32 val;

        val = ioread32(common->base + reg);
        val &= ~mask;
        val |= (data & mask);
        iowrite32(val, common->base + reg);
}

#define rcar_thermal_read(p, r) _rcar_thermal_read(p, REG_ ##r)
static u32 _rcar_thermal_read(struct rcar_thermal_priv *priv, u32 reg)
{
        return ioread32(priv->base + reg);
}

#define rcar_thermal_write(p, r, d) _rcar_thermal_write(p, REG_ ##r, d)
static void _rcar_thermal_write(struct rcar_thermal_priv *priv,
                                u32 reg, u32 data)
{
        iowrite32(data, priv->base + reg);
}

#define rcar_thermal_bset(p, r, m, d) _rcar_thermal_bset(p, REG_ ##r, m, d)
static void _rcar_thermal_bset(struct rcar_thermal_priv *priv, u32 reg,
                               u32 mask, u32 data)
{
        u32 val;

        val = ioread32(priv->base + reg);
        val &= ~mask;
        val |= (data & mask);
        iowrite32(val, priv->base + reg);
}

/*
 *              zone device functions
 */
static int rcar_thermal_update_temp(struct rcar_thermal_priv *priv)
{
        struct device *dev = rcar_priv_to_dev(priv);
        int i;
        u32 ctemp, old, new;
        int ret = -EINVAL;

        mutex_lock(&priv->lock);

        /*
         * TSC decides a value of CPTAP automatically,
         * and this is the conditions which validate interrupt.
         */
        rcar_thermal_bset(priv, THSCR, CPCTL, CPCTL);

        ctemp = 0;
        old = ~0;
        for (i = 0; i < 128; i++) {
                /*
                 * we need to wait 300us after changing comparator offset
                 * to get stable temperature.
                 * see "Usage Notes" on datasheet
                 */
                udelay(300);

                new = rcar_thermal_read(priv, THSSR) & CTEMP;
                if (new == old) {
                        ctemp = new;
                        break;
                }
                old = new;
        }

        if (!ctemp) {
                dev_err(dev, "thermal sensor was broken\n");
                goto err_out_unlock;
        }

        /*
         * enable IRQ
         */
        if (rcar_has_irq_support(priv)) {
                if (priv->chip->has_filonoff)
                        rcar_thermal_write(priv, FILONOFF, 0);

                /* enable Rising/Falling edge interrupt */
                rcar_thermal_write(priv, POSNEG,  0x1);
                rcar_thermal_write(priv, INTCTRL, (((ctemp - 0) << 8) |
                                                   ((ctemp - 1) << 0)));
        }

        dev_dbg(dev, "thermal%d  %d -> %d\n", priv->id, priv->ctemp, ctemp);

        priv->ctemp = ctemp;
        ret = 0;
err_out_unlock:
        mutex_unlock(&priv->lock);
        return ret;
}

static int rcar_thermal_get_current_temp(struct rcar_thermal_priv *priv,
                                         int *temp)
{
        int tmp;
        int ret;

        ret = rcar_thermal_update_temp(priv);
        if (ret < 0)
                return ret;

        mutex_lock(&priv->lock);
        tmp =  MCELSIUS((priv->ctemp * 5) - 65);
        mutex_unlock(&priv->lock);

        if ((tmp < MCELSIUS(-45)) || (tmp > MCELSIUS(125))) {
                struct device *dev = rcar_priv_to_dev(priv);

                dev_err(dev, "it couldn't measure temperature correctly\n");
                return -EIO;
        }

        *temp = tmp;

        return 0;
}

static int rcar_thermal_of_get_temp(void *data, int *temp)
{
        struct rcar_thermal_priv *priv = data;

        return rcar_thermal_get_current_temp(priv, temp);
}

static int rcar_thermal_get_temp(struct thermal_zone_device *zone, int *temp)
{
        struct rcar_thermal_priv *priv = rcar_zone_to_priv(zone);

        return rcar_thermal_get_current_temp(priv, temp);
}

static int rcar_thermal_get_trip_type(struct thermal_zone_device *zone,
                                      int trip, enum thermal_trip_type *type)
{
        struct rcar_thermal_priv *priv = rcar_zone_to_priv(zone);
        struct device *dev = rcar_priv_to_dev(priv);

        /* see rcar_thermal_get_temp() */
        switch (trip) {
        case 0: /* +90 <= temp */
                *type = THERMAL_TRIP_CRITICAL;
                break;
        default:
                dev_err(dev, "rcar driver trip error\n");
                return -EINVAL;
        }

        return 0;
}

static int rcar_thermal_get_trip_temp(struct thermal_zone_device *zone,
                                      int trip, int *temp)
{
        struct rcar_thermal_priv *priv = rcar_zone_to_priv(zone);
        struct device *dev = rcar_priv_to_dev(priv);

        /* see rcar_thermal_get_temp() */
        switch (trip) {
        case 0: /* +90 <= temp */
                *temp = MCELSIUS(90);
                break;
        default:
                dev_err(dev, "rcar driver trip error\n");
                return -EINVAL;
        }

        return 0;
}

static int rcar_thermal_notify(struct thermal_zone_device *zone,
                               int trip, enum thermal_trip_type type)
{
        struct rcar_thermal_priv *priv = rcar_zone_to_priv(zone);
        struct device *dev = rcar_priv_to_dev(priv);

        switch (type) {
        case THERMAL_TRIP_CRITICAL:
                /* FIXME */
                dev_warn(dev, "Thermal reached to critical temperature\n");
                break;
        default:
                break;
        }

        return 0;
}

static const struct thermal_zone_of_device_ops rcar_thermal_zone_of_ops = {
        .get_temp       = rcar_thermal_of_get_temp,
};

static struct thermal_zone_device_ops rcar_thermal_zone_ops = {
        .get_temp       = rcar_thermal_get_temp,
        .get_trip_type  = rcar_thermal_get_trip_type,
        .get_trip_temp  = rcar_thermal_get_trip_temp,
        .notify         = rcar_thermal_notify,
};

/*
 *              interrupt
 */
#define rcar_thermal_irq_enable(p)      _rcar_thermal_irq_ctrl(p, 1)
#define rcar_thermal_irq_disable(p)     _rcar_thermal_irq_ctrl(p, 0)
static void _rcar_thermal_irq_ctrl(struct rcar_thermal_priv *priv, int enable)
{
        struct rcar_thermal_common *common = priv->common;
        unsigned long flags;
        u32 mask = 0x3 << rcar_id_to_shift(priv); /* enable Rising/Falling */

        if (!rcar_has_irq_support(priv))
                return;

        spin_lock_irqsave(&common->lock, flags);

        rcar_thermal_common_bset(common, INTMSK, mask, enable ? 0 : mask);

        spin_unlock_irqrestore(&common->lock, flags);
}

static void rcar_thermal_work(struct work_struct *work)
{
        struct rcar_thermal_priv *priv;
        int cctemp, nctemp;
        int ret;

        priv = container_of(work, struct rcar_thermal_priv, work.work);

        ret = rcar_thermal_get_current_temp(priv, &cctemp);
        if (ret < 0)
                return;

        ret = rcar_thermal_update_temp(priv);
        if (ret < 0)
                return;

        rcar_thermal_irq_enable(priv);

        ret = rcar_thermal_get_current_temp(priv, &nctemp);
        if (ret < 0)
                return;

        if (nctemp != cctemp)
                thermal_zone_device_update(priv->zone,
                                           THERMAL_EVENT_UNSPECIFIED);
}

static u32 rcar_thermal_had_changed(struct rcar_thermal_priv *priv, u32 status)
{
        struct device *dev = rcar_priv_to_dev(priv);

        status = (status >> rcar_id_to_shift(priv)) & 0x3;

        if (status) {
                dev_dbg(dev, "thermal%d %s%s\n",
                        priv->id,
                        (status & 0x2) ? "Rising " : "",
                        (status & 0x1) ? "Falling" : "");
        }

        return status;
}

static irqreturn_t rcar_thermal_irq(int irq, void *data)
{
        struct rcar_thermal_common *common = data;
        struct rcar_thermal_priv *priv;
        unsigned long flags;
        u32 status, mask;

        spin_lock_irqsave(&common->lock, flags);

        mask    = rcar_thermal_common_read(common, INTMSK);
        status  = rcar_thermal_common_read(common, STR);
        rcar_thermal_common_write(common, STR, 0x000F0F0F & mask);

        spin_unlock_irqrestore(&common->lock, flags);

        status = status & ~mask;

        /*
         * check the status
         */
        rcar_thermal_for_each_priv(priv, common) {
                if (rcar_thermal_had_changed(priv, status)) {
                        rcar_thermal_irq_disable(priv);
                        schedule_delayed_work(&priv->work,
                                              msecs_to_jiffies(300));
                }
        }

        return IRQ_HANDLED;
}

/*
 *              platform functions
 */
static int rcar_thermal_remove(struct platform_device *pdev)
{
        struct rcar_thermal_common *common = platform_get_drvdata(pdev);
        struct device *dev = &pdev->dev;
        struct rcar_thermal_priv *priv;

        rcar_thermal_for_each_priv(priv, common) {
                rcar_thermal_irq_disable(priv);
                if (priv->chip->use_of_thermal)
                        thermal_remove_hwmon_sysfs(priv->zone);
                else
                        thermal_zone_device_unregister(priv->zone);
        }

        pm_runtime_put(dev);
        pm_runtime_disable(dev);

        return 0;
}

static int rcar_thermal_probe(struct platform_device *pdev)
{
        struct rcar_thermal_common *common;
        struct rcar_thermal_priv *priv;
        struct device *dev = &pdev->dev;
        struct resource *res, *irq;
        const struct rcar_thermal_chip *chip = of_device_get_match_data(dev);
        int mres = 0;
        int i;
        int ret = -ENODEV;
        int idle = IDLE_INTERVAL;
        u32 enr_bits = 0;

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

        platform_set_drvdata(pdev, common);

        INIT_LIST_HEAD(&common->head);
        spin_lock_init(&common->lock);
        common->dev = dev;

        pm_runtime_enable(dev);
        pm_runtime_get_sync(dev);

        for (i = 0; i < chip->nirqs; i++) {
                irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
                if (!irq)
                        continue;
                if (!common->base) {
                        /*
                         * platform has IRQ support.
                         * Then, driver uses common registers
                         * rcar_has_irq_support() will be enabled
                         */
                        res = platform_get_resource(pdev, IORESOURCE_MEM,
                                                    mres++);
                        common->base = devm_ioremap_resource(dev, res);
                        if (IS_ERR(common->base))
                                return PTR_ERR(common->base);

                        idle = 0; /* polling delay is not needed */
                }

                ret = devm_request_irq(dev, irq->start, rcar_thermal_irq,
                                       IRQF_SHARED, dev_name(dev), common);
                if (ret) {
                        dev_err(dev, "irq request failed\n ");
                        goto error_unregister;
                }

                /* update ENR bits */
                if (chip->irq_per_ch)
                        enr_bits |= 1 << i;
        }

        for (i = 0;; i++) {
                res = platform_get_resource(pdev, IORESOURCE_MEM, mres++);
                if (!res)
                        break;

                priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
                if (!priv) {
                        ret = -ENOMEM;
                        goto error_unregister;
                }

                priv->base = devm_ioremap_resource(dev, res);
                if (IS_ERR(priv->base)) {
                        ret = PTR_ERR(priv->base);
                        goto error_unregister;
                }

                priv->common = common;
                priv->id = i;
                priv->chip = chip;
                mutex_init(&priv->lock);
                INIT_LIST_HEAD(&priv->list);
                INIT_DELAYED_WORK(&priv->work, rcar_thermal_work);
                ret = rcar_thermal_update_temp(priv);
                if (ret < 0)
                        goto error_unregister;

                if (chip->use_of_thermal)
                        priv->zone = devm_thermal_zone_of_sensor_register(
                                                dev, i, priv,
                                                &rcar_thermal_zone_of_ops);
                else
                        priv->zone = thermal_zone_device_register(
                                                "rcar_thermal",
                                                1, 0, priv,
                                                &rcar_thermal_zone_ops, NULL, 0,
                                                idle);
                if (IS_ERR(priv->zone)) {
                        dev_err(dev, "can't register thermal zone\n");
                        ret = PTR_ERR(priv->zone);
                        priv->zone = NULL;
                        goto error_unregister;
                }

                if (chip->use_of_thermal) {
                        /*
                         * thermal_zone doesn't enable hwmon as default,
                         * but, enable it here to keep compatible
                         */
                        priv->zone->tzp->no_hwmon = false;
                        ret = thermal_add_hwmon_sysfs(priv->zone);
                        if (ret)
                                goto error_unregister;
                }

                rcar_thermal_irq_enable(priv);

                list_move_tail(&priv->list, &common->head);

                /* update ENR bits */
                if (!chip->irq_per_ch)
                        enr_bits |= 3 << (i * 8);
        }

        if (common->base && enr_bits)
                rcar_thermal_common_write(common, ENR, enr_bits);

        dev_info(dev, "%d sensor probed\n", i);

        return 0;

error_unregister:
        rcar_thermal_remove(pdev);

        return ret;
}

#ifdef CONFIG_PM_SLEEP
static int rcar_thermal_suspend(struct device *dev)
{
        struct rcar_thermal_common *common = dev_get_drvdata(dev);
        struct rcar_thermal_priv *priv = list_first_entry(&common->head,
                                                          typeof(*priv), list);

        if (priv->chip->needs_suspend_resume) {
                rcar_thermal_common_write(common, ENR, 0);
                rcar_thermal_irq_disable(priv);
                rcar_thermal_bset(priv, THSCR, CPCTL, 0);
        }

        return 0;
}

static int rcar_thermal_resume(struct device *dev)
{
        struct rcar_thermal_common *common = dev_get_drvdata(dev);
        struct rcar_thermal_priv *priv = list_first_entry(&common->head,
                                                          typeof(*priv), list);
        int ret;

        if (priv->chip->needs_suspend_resume) {
                ret = rcar_thermal_update_temp(priv);
                if (ret < 0)
                        return ret;
                rcar_thermal_irq_enable(priv);
                rcar_thermal_common_write(common, ENR, 0x03);
        }

        return 0;
}
#endif

static SIMPLE_DEV_PM_OPS(rcar_thermal_pm_ops, rcar_thermal_suspend,
                         rcar_thermal_resume);

static struct platform_driver rcar_thermal_driver = {
        .driver = {
                .name   = "rcar_thermal",
                .pm = &rcar_thermal_pm_ops,
                .of_match_table = rcar_thermal_dt_ids,
        },
        .probe          = rcar_thermal_probe,
        .remove         = rcar_thermal_remove,
};
module_platform_driver(rcar_thermal_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("R-Car THS/TSC thermal sensor driver");
MODULE_AUTHOR("Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>");