// SPDX-License-Identifier: GPL-2.0
/*
 *  R-Car Gen3, Gen4 and RZ/G2 THS thermal sensor driver
 *  Based on rcar_thermal.c and work from Hien Dang and Khiem Nguyen.
 *
 * Copyright (C) 2016 Renesas Electronics Corporation.
 * Copyright (C) 2016 Sang Engineering
 */
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/thermal.h>

#include "../thermal_hwmon.h"

/* Register offsets */
#define REG_GEN3_IRQSTR         0x04
#define REG_GEN3_IRQMSK         0x08
#define REG_GEN3_IRQCTL         0x0c
#define REG_GEN3_IRQEN          0x10
#define REG_GEN3_IRQTEMP1       0x14
#define REG_GEN3_IRQTEMP2       0x18
#define REG_GEN3_IRQTEMP3       0x1c
#define REG_GEN3_THCTR          0x20
#define REG_GEN3_TEMP           0x28
#define REG_GEN3_THCODE1        0x50
#define REG_GEN3_THCODE2        0x54
#define REG_GEN3_THCODE3        0x58
#define REG_GEN3_PTAT1          0x5c
#define REG_GEN3_PTAT2          0x60
#define REG_GEN3_PTAT3          0x64
#define REG_GEN3_THSCP          0x68
#define REG_GEN4_THSFMON00      0x180
#define REG_GEN4_THSFMON01      0x184
#define REG_GEN4_THSFMON02      0x188
#define REG_GEN4_THSFMON15      0x1bc
#define REG_GEN4_THSFMON16      0x1c0
#define REG_GEN4_THSFMON17      0x1c4

/* IRQ{STR,MSK,EN} bits */
#define IRQ_TEMP1               BIT(0)
#define IRQ_TEMP2               BIT(1)
#define IRQ_TEMP3               BIT(2)
#define IRQ_TEMPD1              BIT(3)
#define IRQ_TEMPD2              BIT(4)
#define IRQ_TEMPD3              BIT(5)

/* THCTR bits */
#define THCTR_PONM      BIT(6)
#define THCTR_THSST     BIT(0)

/* THSCP bits */
#define THSCP_COR_PARA_VLD      (BIT(15) | BIT(14))

#define CTEMP_MASK      0xfff

#define MCELSIUS(temp)  ((temp) * 1000)
#define GEN3_FUSE_MASK  0xfff
#define GEN4_FUSE_MASK  0xfff

#define TSC_MAX_NUM     5

struct rcar_gen3_thermal_priv;

struct rcar_gen3_thermal_fuse_info {
        u32 ptat[3];
        u32 thcode[3];
        u32 mask;
};

struct rcar_gen3_thermal_fuse_default {
        u32 ptat[3];
        u32 thcodes[TSC_MAX_NUM][3];
};

struct rcar_thermal_info {
        int scale;
        int adj_below;
        int adj_above;
        const struct rcar_gen3_thermal_fuse_info *fuses;
        const struct rcar_gen3_thermal_fuse_default *fuse_defaults;
};

struct equation_set_coef {
        int a;
        int b;
};

struct rcar_gen3_thermal_tsc {
        struct rcar_gen3_thermal_priv *priv;
        void __iomem *base;
        struct thermal_zone_device *zone;
        /* Different coefficients are used depending on a threshold. */
        struct {
                struct equation_set_coef below;
                struct equation_set_coef above;
        } coef;
        int thcode[3];
};

struct rcar_gen3_thermal_priv {
        struct rcar_gen3_thermal_tsc *tscs[TSC_MAX_NUM];
        struct thermal_zone_device_ops ops;
        unsigned int num_tscs;
        int ptat[3];
        int tj_t;
        const struct rcar_thermal_info *info;
};

static inline u32 rcar_gen3_thermal_read(struct rcar_gen3_thermal_tsc *tsc,
                                         u32 reg)
{
        return ioread32(tsc->base + reg);
}

static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc,
                                           u32 reg, u32 data)
{
        iowrite32(data, tsc->base + reg);
}

/*
 * Linear approximation for temperature
 *
 * [temp] = ((thadj - [reg]) * a) / b + adj
 * [reg] = thadj - ([temp] - adj) * b / a
 *
 * The constants a and b are calculated using two triplets of int values PTAT
 * and THCODE. PTAT and THCODE can either be read from hardware or use hard
 * coded values from the driver. The formula to calculate a and b are taken from
 * the datasheet. Different calculations are needed for a and b depending on
 * if the input variables ([temp] or [reg]) are above or below a threshold. The
 * threshold is also calculated from PTAT and THCODE using formulas from the
 * datasheet.
 *
 * The constant thadj is one of the THCODE values, which one to use depends on
 * the threshold and input value.
 *
 * The constants adj is taken verbatim from the datasheet. Two values exists,
 * which one to use depends on the input value and the calculated threshold.
 * Furthermore different SoC models supported by the driver have different sets
 * of values. The values for each model are stored in the device match data.
 */

static void rcar_gen3_thermal_shared_coefs(struct rcar_gen3_thermal_priv *priv)
{
        priv->tj_t =
                DIV_ROUND_CLOSEST((priv->ptat[1] - priv->ptat[2]) * priv->info->scale,
                                  priv->ptat[0] - priv->ptat[2])
                + priv->info->adj_below;
}
static void rcar_gen3_thermal_tsc_coefs(struct rcar_gen3_thermal_priv *priv,
                                        struct rcar_gen3_thermal_tsc *tsc)
{
        tsc->coef.below.a = priv->info->scale * (priv->ptat[2] - priv->ptat[1]);
        tsc->coef.above.a = priv->info->scale * (priv->ptat[0] - priv->ptat[1]);

        tsc->coef.below.b = (priv->ptat[2] - priv->ptat[0]) * (tsc->thcode[2] - tsc->thcode[1]);
        tsc->coef.above.b = (priv->ptat[0] - priv->ptat[2]) * (tsc->thcode[1] - tsc->thcode[0]);
}

static int rcar_gen3_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
{
        struct rcar_gen3_thermal_tsc *tsc = thermal_zone_device_priv(tz);
        struct rcar_gen3_thermal_priv *priv = tsc->priv;
        const struct equation_set_coef *coef;
        int adj, decicelsius, reg, thcode;

        /* Read register and convert to millidegree Celsius */
        reg = rcar_gen3_thermal_read(tsc, REG_GEN3_TEMP) & CTEMP_MASK;

        if (reg < tsc->thcode[1]) {
                adj = priv->info->adj_below;
                coef = &tsc->coef.below;
                thcode = tsc->thcode[2];
        } else {
                adj = priv->info->adj_above;
                coef = &tsc->coef.above;
                thcode = tsc->thcode[0];
        }

        /*
         * The dividend can't be grown as it might overflow, instead shorten the
         * divisor to convert to decidegree Celsius. If we convert after the
         * division precision is lost as we will scale up from whole degrees
         * Celsius.
         */
        decicelsius = DIV_ROUND_CLOSEST(coef->a * (thcode - reg), coef->b / 10);

        /* Guaranteed operating range is -40C to 125C. */

        /* Reporting is done in millidegree Celsius */
        *temp = decicelsius * 100 + adj * 1000;

        return 0;
}

static int rcar_gen3_thermal_mcelsius_to_temp(struct rcar_gen3_thermal_tsc *tsc,
                                              int mcelsius)
{
        struct rcar_gen3_thermal_priv *priv = tsc->priv;
        const struct equation_set_coef *coef;
        int adj, celsius, thcode;

        celsius = DIV_ROUND_CLOSEST(mcelsius, 1000);
        if (celsius < priv->tj_t) {
                coef = &tsc->coef.below;
                adj = priv->info->adj_below;
                thcode = tsc->thcode[2];
        } else {
                coef = &tsc->coef.above;
                adj = priv->info->adj_above;
                thcode = tsc->thcode[0];
        }

        return thcode - DIV_ROUND_CLOSEST((celsius - adj) * coef->b, coef->a);
}

static int rcar_gen3_thermal_set_trips(struct thermal_zone_device *tz, int low, int high)
{
        struct rcar_gen3_thermal_tsc *tsc = thermal_zone_device_priv(tz);
        u32 irqmsk = 0;

        if (low != -INT_MAX) {
                irqmsk |= IRQ_TEMPD1;
                rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP1,
                                        rcar_gen3_thermal_mcelsius_to_temp(tsc, low));
        }

        if (high != INT_MAX) {
                irqmsk |= IRQ_TEMP2;
                rcar_gen3_thermal_write(tsc, REG_GEN3_IRQTEMP2,
                                        rcar_gen3_thermal_mcelsius_to_temp(tsc, high));
        }

        rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, irqmsk);

        return 0;
}

static const struct thermal_zone_device_ops rcar_gen3_tz_of_ops = {
        .get_temp       = rcar_gen3_thermal_get_temp,
        .set_trips      = rcar_gen3_thermal_set_trips,
};

static irqreturn_t rcar_gen3_thermal_irq(int irq, void *data)
{
        struct rcar_gen3_thermal_priv *priv = data;
        unsigned int i;
        u32 status;

        for (i = 0; i < priv->num_tscs; i++) {
                status = rcar_gen3_thermal_read(priv->tscs[i], REG_GEN3_IRQSTR);
                rcar_gen3_thermal_write(priv->tscs[i], REG_GEN3_IRQSTR, 0);
                if (status && priv->tscs[i]->zone)
                        thermal_zone_device_update(priv->tscs[i]->zone,
                                                   THERMAL_EVENT_UNSPECIFIED);
        }

        return IRQ_HANDLED;
}

static void rcar_gen3_thermal_fetch_fuses(struct rcar_gen3_thermal_priv *priv)
{
        const struct rcar_gen3_thermal_fuse_info *fuses = priv->info->fuses;

        /*
         * Set the pseudo calibration points with fused values.
         * PTAT is shared between all TSCs but only fused for the first
         * TSC while THCODEs are fused for each TSC.
         */
        priv->ptat[0] = rcar_gen3_thermal_read(priv->tscs[0], fuses->ptat[0])
                & fuses->mask;
        priv->ptat[1] = rcar_gen3_thermal_read(priv->tscs[0], fuses->ptat[1])
                & fuses->mask;
        priv->ptat[2] = rcar_gen3_thermal_read(priv->tscs[0], fuses->ptat[2])
                & fuses->mask;

        for (unsigned int i = 0; i < priv->num_tscs; i++) {
                struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];

                tsc->thcode[0] = rcar_gen3_thermal_read(tsc, fuses->thcode[0])
                        & fuses->mask;
                tsc->thcode[1] = rcar_gen3_thermal_read(tsc, fuses->thcode[1])
                        & fuses->mask;
                tsc->thcode[2] = rcar_gen3_thermal_read(tsc, fuses->thcode[2])
                        & fuses->mask;
        }
}

static bool rcar_gen3_thermal_read_fuses(struct rcar_gen3_thermal_priv *priv)
{
        const struct rcar_gen3_thermal_fuse_default *fuse_defaults = priv->info->fuse_defaults;
        unsigned int i;
        u32 thscp;

        /* If fuses are not set, fallback to pseudo values. */
        thscp = rcar_gen3_thermal_read(priv->tscs[0], REG_GEN3_THSCP);
        if (!priv->info->fuses ||
            (thscp & THSCP_COR_PARA_VLD) != THSCP_COR_PARA_VLD) {
                /* Default THCODE values in case FUSEs are not set. */
                priv->ptat[0] = fuse_defaults->ptat[0];
                priv->ptat[1] = fuse_defaults->ptat[1];
                priv->ptat[2] = fuse_defaults->ptat[2];

                for (i = 0; i < priv->num_tscs; i++) {
                        struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];

                        tsc->thcode[0] = fuse_defaults->thcodes[i][0];
                        tsc->thcode[1] = fuse_defaults->thcodes[i][1];
                        tsc->thcode[2] = fuse_defaults->thcodes[i][2];
                }

                return false;
        }

        rcar_gen3_thermal_fetch_fuses(priv);

        return true;
}

static void rcar_gen3_thermal_init(struct rcar_gen3_thermal_priv *priv,
                                   struct rcar_gen3_thermal_tsc *tsc)
{
        u32 reg_val;

        reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
        reg_val &= ~THCTR_PONM;
        rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);

        usleep_range(1000, 2000);

        rcar_gen3_thermal_write(tsc, REG_GEN3_IRQCTL, 0);
        rcar_gen3_thermal_write(tsc, REG_GEN3_IRQMSK, 0);
        if (priv->ops.set_trips)
                rcar_gen3_thermal_write(tsc, REG_GEN3_IRQEN,
                                        IRQ_TEMPD1 | IRQ_TEMP2);

        reg_val = rcar_gen3_thermal_read(tsc, REG_GEN3_THCTR);
        reg_val |= THCTR_THSST;
        rcar_gen3_thermal_write(tsc, REG_GEN3_THCTR, reg_val);

        usleep_range(1000, 2000);
}

static const struct rcar_gen3_thermal_fuse_info rcar_gen3_thermal_fuse_info_gen3 = {
        .ptat = { REG_GEN3_PTAT1, REG_GEN3_PTAT2, REG_GEN3_PTAT3 },
        .thcode = { REG_GEN3_THCODE1, REG_GEN3_THCODE2, REG_GEN3_THCODE3 },
        .mask = GEN3_FUSE_MASK,
};

static const struct rcar_gen3_thermal_fuse_info rcar_gen3_thermal_fuse_info_gen4 = {
        .ptat = { REG_GEN4_THSFMON16, REG_GEN4_THSFMON17, REG_GEN4_THSFMON15 },
        .thcode = { REG_GEN4_THSFMON01, REG_GEN4_THSFMON02, REG_GEN4_THSFMON00 },
        .mask = GEN4_FUSE_MASK,
};

static const struct rcar_gen3_thermal_fuse_default rcar_gen3_thermal_fuse_default_info_gen3 = {
        .ptat = { 2631, 1509, 435 },
        .thcodes = {
                { 3397, 2800, 2221 },
                { 3393, 2795, 2216 },
                { 3389, 2805, 2237 },
                { 3415, 2694, 2195 },
                { 3356, 2724, 2244 },
        },
};

static const struct rcar_gen3_thermal_fuse_default rcar_gen3_thermal_fuse_default_info_gen4 = {
        .ptat = { 3274, 2164, 985 },
        .thcodes = { /* All four THS units share the same trimming */
                { 3218, 2617, 1980 },
                { 3218, 2617, 1980 },
                { 3218, 2617, 1980 },
                { 3218, 2617, 1980 },
        }
};

static const struct rcar_thermal_info rcar_m3w_thermal_info = {
        .scale = 157,
        .adj_below = -41,
        .adj_above = 116,
        .fuses = &rcar_gen3_thermal_fuse_info_gen3,
        .fuse_defaults = &rcar_gen3_thermal_fuse_default_info_gen3,
};

static const struct rcar_thermal_info rcar_gen3_thermal_info = {
        .scale = 167,
        .adj_below = -41,
        .adj_above = 126,
        .fuses = &rcar_gen3_thermal_fuse_info_gen3,
        .fuse_defaults = &rcar_gen3_thermal_fuse_default_info_gen3,
};

static const struct rcar_thermal_info rcar_s4_thermal_info = {
        .scale = 167,
        .adj_below = -41,
        .adj_above = 126,
        .fuses = &rcar_gen3_thermal_fuse_info_gen4,
        .fuse_defaults = &rcar_gen3_thermal_fuse_default_info_gen3,
};

static const struct rcar_thermal_info rcar_gen4_thermal_info = {
        .scale = 167,
        .adj_below = -41,
        .adj_above = 126,
        .fuses = &rcar_gen3_thermal_fuse_info_gen4,
        .fuse_defaults = &rcar_gen3_thermal_fuse_default_info_gen4,
};

static const struct of_device_id rcar_gen3_thermal_dt_ids[] = {
        {
                .compatible = "renesas,r8a774a1-thermal",
                .data = &rcar_m3w_thermal_info,
        },
        {
                .compatible = "renesas,r8a774b1-thermal",
                .data = &rcar_gen3_thermal_info,
        },
        {
                .compatible = "renesas,r8a774e1-thermal",
                .data = &rcar_gen3_thermal_info,
        },
        {
                .compatible = "renesas,r8a7795-thermal",
                .data = &rcar_gen3_thermal_info,
        },
        {
                .compatible = "renesas,r8a7796-thermal",
                .data = &rcar_m3w_thermal_info,
        },
        {
                .compatible = "renesas,r8a77961-thermal",
                .data = &rcar_m3w_thermal_info,
        },
        {
                .compatible = "renesas,r8a77965-thermal",
                .data = &rcar_gen3_thermal_info,
        },
        {
                .compatible = "renesas,r8a77980-thermal",
                .data = &rcar_gen3_thermal_info,
        },
        {
                .compatible = "renesas,r8a779a0-thermal",
                .data = &rcar_gen3_thermal_info,
        },
        {
                .compatible = "renesas,r8a779f0-thermal",
                .data = &rcar_s4_thermal_info,
        },
        {
                .compatible = "renesas,r8a779g0-thermal",
                .data = &rcar_gen4_thermal_info,
        },
        {
                .compatible = "renesas,r8a779h0-thermal",
                .data = &rcar_gen4_thermal_info,
        },
        {},
};
MODULE_DEVICE_TABLE(of, rcar_gen3_thermal_dt_ids);

static void rcar_gen3_thermal_remove(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;

        pm_runtime_put(dev);
        pm_runtime_disable(dev);
}

static void rcar_gen3_hwmon_action(void *data)
{
        struct thermal_zone_device *zone = data;

        thermal_remove_hwmon_sysfs(zone);
}

static int rcar_gen3_thermal_request_irqs(struct rcar_gen3_thermal_priv *priv,
                                          struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        unsigned int i;
        char *irqname;
        int ret, irq;

        for (i = 0; i < 2; i++) {
                irq = platform_get_irq_optional(pdev, i);
                if (irq < 0)
                        return irq;

                irqname = devm_kasprintf(dev, GFP_KERNEL, "%s:ch%d",
                                         dev_name(dev), i);
                if (!irqname)
                        return -ENOMEM;

                ret = devm_request_threaded_irq(dev, irq, NULL,
                                                rcar_gen3_thermal_irq,
                                                IRQF_ONESHOT, irqname, priv);
                if (ret)
                        return ret;
        }

        return 0;
}

static int rcar_gen3_thermal_probe(struct platform_device *pdev)
{
        struct rcar_gen3_thermal_priv *priv;
        struct device *dev = &pdev->dev;
        struct resource *res;
        struct thermal_zone_device *zone;
        unsigned int i;
        int ret;

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

        priv->ops = rcar_gen3_tz_of_ops;

        priv->info = of_device_get_match_data(dev);
        platform_set_drvdata(pdev, priv);

        if (rcar_gen3_thermal_request_irqs(priv, pdev))
                priv->ops.set_trips = NULL;

        pm_runtime_enable(dev);
        pm_runtime_get_sync(dev);

        for (i = 0; i < TSC_MAX_NUM; i++) {
                struct rcar_gen3_thermal_tsc *tsc;

                res = platform_get_resource(pdev, IORESOURCE_MEM, i);
                if (!res)
                        break;

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

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

                priv->tscs[i] = tsc;
        }

        priv->num_tscs = i;

        if (!rcar_gen3_thermal_read_fuses(priv))
                dev_info(dev, "No calibration values fused, fallback to driver values\n");

        rcar_gen3_thermal_shared_coefs(priv);

        for (i = 0; i < priv->num_tscs; i++) {
                struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];

                rcar_gen3_thermal_init(priv, tsc);
                rcar_gen3_thermal_tsc_coefs(priv, tsc);

                zone = devm_thermal_of_zone_register(dev, i, tsc, &priv->ops);
                if (IS_ERR(zone)) {
                        dev_err(dev, "Sensor %u: Can't register thermal zone\n", i);
                        ret = PTR_ERR(zone);
                        goto error_unregister;
                }
                tsc->zone = zone;

                ret = thermal_add_hwmon_sysfs(tsc->zone);
                if (ret)
                        goto error_unregister;

                ret = devm_add_action_or_reset(dev, rcar_gen3_hwmon_action, zone);
                if (ret)
                        goto error_unregister;

                dev_info(dev, "Sensor %u: Loaded\n", i);
        }

        if (!priv->num_tscs) {
                ret = -ENODEV;
                goto error_unregister;
        }

        return 0;

error_unregister:
        rcar_gen3_thermal_remove(pdev);

        return ret;
}

static int rcar_gen3_thermal_resume(struct device *dev)
{
        struct rcar_gen3_thermal_priv *priv = dev_get_drvdata(dev);
        unsigned int i;

        for (i = 0; i < priv->num_tscs; i++) {
                struct rcar_gen3_thermal_tsc *tsc = priv->tscs[i];

                rcar_gen3_thermal_init(priv, tsc);
        }

        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(rcar_gen3_thermal_pm_ops, NULL,
                                rcar_gen3_thermal_resume);

static struct platform_driver rcar_gen3_thermal_driver = {
        .driver = {
                .name   = "rcar_gen3_thermal",
                .pm = pm_sleep_ptr(&rcar_gen3_thermal_pm_ops),
                .of_match_table = rcar_gen3_thermal_dt_ids,
        },
        .probe          = rcar_gen3_thermal_probe,
        .remove         = rcar_gen3_thermal_remove,
};
module_platform_driver(rcar_gen3_thermal_driver);

MODULE_LICENSE("GPL v2");
MODULE_DESCRIPTION("R-Car Gen3 THS thermal sensor driver");
MODULE_AUTHOR("Wolfram Sang <wsa+renesas@sang-engineering.com>");