/*
 * OMAP thermal driver interface
 *
 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/
 * Contact:
 *   Eduardo Valentin <eduardo.valentin@ti.com>
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * version 2 as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 *
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/gfp.h>
#include <linux/kernel.h>
#include <linux/workqueue.h>
#include <linux/thermal.h>
#include <linux/cpufreq.h>
#include <linux/cpumask.h>
#include <linux/cpu_cooling.h>
#include <linux/of.h>

#include "ti-thermal.h"
#include "ti-bandgap.h"

/* common data structures */
struct ti_thermal_data {
        struct cpufreq_policy *policy;
        struct thermal_zone_device *ti_thermal;
        struct thermal_zone_device *pcb_tz;
        struct thermal_cooling_device *cool_dev;
        struct ti_bandgap *bgp;
        enum thermal_device_mode mode;
        struct work_struct thermal_wq;
        int sensor_id;
        bool our_zone;
};

static void ti_thermal_work(struct work_struct *work)
{
        struct ti_thermal_data *data = container_of(work,
                                        struct ti_thermal_data, thermal_wq);

        thermal_zone_device_update(data->ti_thermal, THERMAL_EVENT_UNSPECIFIED);

        dev_dbg(&data->ti_thermal->device, "updated thermal zone %s\n",
                data->ti_thermal->type);
}

/**
 * ti_thermal_hotspot_temperature - returns sensor extrapolated temperature
 * @t:  omap sensor temperature
 * @s:  omap sensor slope value
 * @c:  omap sensor const value
 */
static inline int ti_thermal_hotspot_temperature(int t, int s, int c)
{
        int delta = t * s / 1000 + c;

        if (delta < 0)
                delta = 0;

        return t + delta;
}

/* thermal zone ops */
/* Get temperature callback function for thermal zone */
static inline int __ti_thermal_get_temp(void *devdata, int *temp)
{
        struct thermal_zone_device *pcb_tz = NULL;
        struct ti_thermal_data *data = devdata;
        struct ti_bandgap *bgp;
        const struct ti_temp_sensor *s;
        int ret, tmp, slope, constant;
        int pcb_temp;

        if (!data)
                return 0;

        bgp = data->bgp;
        s = &bgp->conf->sensors[data->sensor_id];

        ret = ti_bandgap_read_temperature(bgp, data->sensor_id, &tmp);
        if (ret)
                return ret;

        /* Default constants */
        slope = thermal_zone_get_slope(data->ti_thermal);
        constant = thermal_zone_get_offset(data->ti_thermal);

        pcb_tz = data->pcb_tz;
        /* In case pcb zone is available, use the extrapolation rule with it */
        if (!IS_ERR(pcb_tz)) {
                ret = thermal_zone_get_temp(pcb_tz, &pcb_temp);
                if (!ret) {
                        tmp -= pcb_temp; /* got a valid PCB temp */
                        slope = s->slope_pcb;
                        constant = s->constant_pcb;
                } else {
                        dev_err(bgp->dev,
                                "Failed to read PCB state. Using defaults\n");
                        ret = 0;
                }
        }
        *temp = ti_thermal_hotspot_temperature(tmp, slope, constant);

        return ret;
}

static inline int ti_thermal_get_temp(struct thermal_zone_device *thermal,
                                      int *temp)
{
        struct ti_thermal_data *data = thermal->devdata;

        return __ti_thermal_get_temp(data, temp);
}

static int __ti_thermal_get_trend(void *p, int trip, enum thermal_trend *trend)
{
        struct ti_thermal_data *data = p;
        struct ti_bandgap *bgp;
        int id, tr, ret = 0;

        bgp = data->bgp;
        id = data->sensor_id;

        ret = ti_bandgap_get_trend(bgp, id, &tr);
        if (ret)
                return ret;

        if (tr > 0)
                *trend = THERMAL_TREND_RAISING;
        else if (tr < 0)
                *trend = THERMAL_TREND_DROPPING;
        else
                *trend = THERMAL_TREND_STABLE;

        return 0;
}

static const struct thermal_zone_of_device_ops ti_of_thermal_ops = {
        .get_temp = __ti_thermal_get_temp,
        .get_trend = __ti_thermal_get_trend,
};

static struct ti_thermal_data
*ti_thermal_build_data(struct ti_bandgap *bgp, int id)
{
        struct ti_thermal_data *data;

        data = devm_kzalloc(bgp->dev, sizeof(*data), GFP_KERNEL);
        if (!data) {
                dev_err(bgp->dev, "kzalloc fail\n");
                return NULL;
        }
        data->sensor_id = id;
        data->bgp = bgp;
        data->mode = THERMAL_DEVICE_ENABLED;
        /* pcb_tz will be either valid or PTR_ERR() */
        data->pcb_tz = thermal_zone_get_zone_by_name("pcb");
        INIT_WORK(&data->thermal_wq, ti_thermal_work);

        return data;
}

int ti_thermal_expose_sensor(struct ti_bandgap *bgp, int id,
                             char *domain)
{
        struct ti_thermal_data *data;

        data = ti_bandgap_get_sensor_data(bgp, id);

        if (!data || IS_ERR(data))
                data = ti_thermal_build_data(bgp, id);

        if (!data)
                return -EINVAL;

        /* in case this is specified by DT */
        data->ti_thermal = devm_thermal_zone_of_sensor_register(bgp->dev, id,
                                        data, &ti_of_thermal_ops);
        if (IS_ERR(data->ti_thermal)) {
                dev_err(bgp->dev, "thermal zone device is NULL\n");
                return PTR_ERR(data->ti_thermal);
        }

        ti_bandgap_set_sensor_data(bgp, id, data);
        ti_bandgap_write_update_interval(bgp, data->sensor_id,
                                        data->ti_thermal->polling_delay);

        return 0;
}

int ti_thermal_remove_sensor(struct ti_bandgap *bgp, int id)
{
        struct ti_thermal_data *data;

        data = ti_bandgap_get_sensor_data(bgp, id);

        if (data && data->ti_thermal) {
                if (data->our_zone)
                        thermal_zone_device_unregister(data->ti_thermal);
        }

        return 0;
}

int ti_thermal_report_sensor_temperature(struct ti_bandgap *bgp, int id)
{
        struct ti_thermal_data *data;

        data = ti_bandgap_get_sensor_data(bgp, id);

        schedule_work(&data->thermal_wq);

        return 0;
}

int ti_thermal_register_cpu_cooling(struct ti_bandgap *bgp, int id)
{
        struct ti_thermal_data *data;
        struct device_node *np = bgp->dev->of_node;

        /*
         * We are assuming here that if one deploys the zone
         * using DT, then it must be aware that the cooling device
         * loading has to happen via cpufreq driver.
         */
        if (of_find_property(np, "#thermal-sensor-cells", NULL))
                return 0;

        data = ti_bandgap_get_sensor_data(bgp, id);
        if (!data || IS_ERR(data))
                data = ti_thermal_build_data(bgp, id);

        if (!data)
                return -EINVAL;

        data->policy = cpufreq_cpu_get(0);
        if (!data->policy) {
                pr_debug("%s: CPUFreq policy not found\n", __func__);
                return -EPROBE_DEFER;
        }

        /* Register cooling device */
        data->cool_dev = cpufreq_cooling_register(data->policy);
        if (IS_ERR(data->cool_dev)) {
                int ret = PTR_ERR(data->cool_dev);
                dev_err(bgp->dev, "Failed to register cpu cooling device %d\n",
                        ret);
                cpufreq_cpu_put(data->policy);

                return ret;
        }
        ti_bandgap_set_sensor_data(bgp, id, data);

        return 0;
}

int ti_thermal_unregister_cpu_cooling(struct ti_bandgap *bgp, int id)
{
        struct ti_thermal_data *data;

        data = ti_bandgap_get_sensor_data(bgp, id);

        if (data) {
                cpufreq_cooling_unregister(data->cool_dev);
                if (data->policy)
                        cpufreq_cpu_put(data->policy);
        }

        return 0;
}