/*
 * ST Thermal Sensor Driver core routines
 * Author: Ajit Pal Singh <ajitpal.singh@st.com>
 *
 * Copyright (C) 2003-2014 STMicroelectronics (R&D) Limited
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 */

#include <linux/clk.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>

#include "st_thermal.h"

/* The Thermal Framework expects millidegrees */
#define mcelsius(temp)                  ((temp) * 1000)

/*
 * Function to allocate regfields which are common
 * between syscfg and memory mapped based sensors
 */
static int st_thermal_alloc_regfields(struct st_thermal_sensor *sensor)
{
        struct device *dev = sensor->dev;
        struct regmap *regmap = sensor->regmap;
        const struct reg_field *reg_fields = sensor->cdata->reg_fields;

        sensor->dcorrect = devm_regmap_field_alloc(dev, regmap,
                                                   reg_fields[DCORRECT]);

        sensor->overflow = devm_regmap_field_alloc(dev, regmap,
                                                   reg_fields[OVERFLOW]);

        sensor->temp_data = devm_regmap_field_alloc(dev, regmap,
                                                    reg_fields[DATA]);

        if (IS_ERR(sensor->dcorrect) ||
            IS_ERR(sensor->overflow) ||
            IS_ERR(sensor->temp_data)) {
                dev_err(dev, "failed to allocate common regfields\n");
                return -EINVAL;
        }

        return sensor->ops->alloc_regfields(sensor);
}

static int st_thermal_sensor_on(struct st_thermal_sensor *sensor)
{
        int ret;
        struct device *dev = sensor->dev;

        ret = clk_prepare_enable(sensor->clk);
        if (ret) {
                dev_err(dev, "failed to enable clk\n");
                return ret;
        }

        ret = sensor->ops->power_ctrl(sensor, POWER_ON);
        if (ret) {
                dev_err(dev, "failed to power on sensor\n");
                clk_disable_unprepare(sensor->clk);
        }

        return ret;
}

static int st_thermal_sensor_off(struct st_thermal_sensor *sensor)
{
        int ret;

        ret = sensor->ops->power_ctrl(sensor, POWER_OFF);
        if (ret)
                return ret;

        clk_disable_unprepare(sensor->clk);

        return 0;
}

static int st_thermal_calibration(struct st_thermal_sensor *sensor)
{
        int ret;
        unsigned int val;
        struct device *dev = sensor->dev;

        /* Check if sensor calibration data is already written */
        ret = regmap_field_read(sensor->dcorrect, &val);
        if (ret) {
                dev_err(dev, "failed to read calibration data\n");
                return ret;
        }

        if (!val) {
                /*
                 * Sensor calibration value not set by bootloader,
                 * default calibration data to be used
                 */
                ret = regmap_field_write(sensor->dcorrect,
                                         sensor->cdata->calibration_val);
                if (ret)
                        dev_err(dev, "failed to set calibration data\n");
        }

        return ret;
}

/* Callback to get temperature from HW*/
static int st_thermal_get_temp(struct thermal_zone_device *th, int *temperature)
{
        struct st_thermal_sensor *sensor = th->devdata;
        struct device *dev = sensor->dev;
        unsigned int temp;
        unsigned int overflow;
        int ret;

        ret = regmap_field_read(sensor->overflow, &overflow);
        if (ret)
                return ret;
        if (overflow)
                return -EIO;

        ret = regmap_field_read(sensor->temp_data, &temp);
        if (ret)
                return ret;

        temp += sensor->cdata->temp_adjust_val;
        temp = mcelsius(temp);

        dev_dbg(dev, "temperature: %d\n", temp);

        *temperature = temp;

        return 0;
}

static int st_thermal_get_trip_type(struct thermal_zone_device *th,
                                int trip, enum thermal_trip_type *type)
{
        struct st_thermal_sensor *sensor = th->devdata;
        struct device *dev = sensor->dev;

        switch (trip) {
        case 0:
                *type = THERMAL_TRIP_CRITICAL;
                break;
        default:
                dev_err(dev, "invalid trip point\n");
                return -EINVAL;
        }

        return 0;
}

static int st_thermal_get_trip_temp(struct thermal_zone_device *th,
                                    int trip, int *temp)
{
        struct st_thermal_sensor *sensor = th->devdata;
        struct device *dev = sensor->dev;

        switch (trip) {
        case 0:
                *temp = mcelsius(sensor->cdata->crit_temp);
                break;
        default:
                dev_err(dev, "Invalid trip point\n");
                return -EINVAL;
        }

        return 0;
}

static struct thermal_zone_device_ops st_tz_ops = {
        .get_temp       = st_thermal_get_temp,
        .get_trip_type  = st_thermal_get_trip_type,
        .get_trip_temp  = st_thermal_get_trip_temp,
};

int st_thermal_register(struct platform_device *pdev,
                        const struct of_device_id *st_thermal_of_match)
{
        struct st_thermal_sensor *sensor;
        struct device *dev = &pdev->dev;
        struct device_node *np = dev->of_node;
        const struct of_device_id *match;

        int polling_delay;
        int ret;

        if (!np) {
                dev_err(dev, "device tree node not found\n");
                return -EINVAL;
        }

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

        sensor->dev = dev;

        match = of_match_device(st_thermal_of_match, dev);
        if (!(match && match->data))
                return -EINVAL;

        sensor->cdata = match->data;
        if (!sensor->cdata->ops)
                return -EINVAL;

        sensor->ops = sensor->cdata->ops;

        ret = (sensor->ops->regmap_init)(sensor);
        if (ret)
                return ret;

        ret = st_thermal_alloc_regfields(sensor);
        if (ret)
                return ret;

        sensor->clk = devm_clk_get(dev, "thermal");
        if (IS_ERR(sensor->clk)) {
                dev_err(dev, "failed to fetch clock\n");
                return PTR_ERR(sensor->clk);
        }

        if (sensor->ops->register_enable_irq) {
                ret = sensor->ops->register_enable_irq(sensor);
                if (ret)
                        return ret;
        }

        ret = st_thermal_sensor_on(sensor);
        if (ret)
                return ret;

        ret = st_thermal_calibration(sensor);
        if (ret)
                goto sensor_off;

        polling_delay = sensor->ops->register_enable_irq ? 0 : 1000;

        sensor->thermal_dev =
                thermal_zone_device_register(dev_name(dev), 1, 0, sensor,
                                             &st_tz_ops, NULL, 0, polling_delay);
        if (IS_ERR(sensor->thermal_dev)) {
                dev_err(dev, "failed to register thermal zone device\n");
                ret = PTR_ERR(sensor->thermal_dev);
                goto sensor_off;
        }

        platform_set_drvdata(pdev, sensor);

        return 0;

sensor_off:
        st_thermal_sensor_off(sensor);

        return ret;
}
EXPORT_SYMBOL_GPL(st_thermal_register);

int st_thermal_unregister(struct platform_device *pdev)
{
        struct st_thermal_sensor *sensor = platform_get_drvdata(pdev);

        st_thermal_sensor_off(sensor);
        thermal_zone_device_unregister(sensor->thermal_dev);

        return 0;
}
EXPORT_SYMBOL_GPL(st_thermal_unregister);

#ifdef CONFIG_PM_SLEEP
static int st_thermal_suspend(struct device *dev)
{
        struct platform_device *pdev = to_platform_device(dev);
        struct st_thermal_sensor *sensor = platform_get_drvdata(pdev);

        return st_thermal_sensor_off(sensor);
}

static int st_thermal_resume(struct device *dev)
{
        int ret;
        struct platform_device *pdev = to_platform_device(dev);
        struct st_thermal_sensor *sensor = platform_get_drvdata(pdev);

        ret = st_thermal_sensor_on(sensor);
        if (ret)
                return ret;

        ret = st_thermal_calibration(sensor);
        if (ret)
                return ret;

        if (sensor->ops->enable_irq) {
                ret = sensor->ops->enable_irq(sensor);
                if (ret)
                        return ret;
        }

        return 0;
}
#endif

SIMPLE_DEV_PM_OPS(st_thermal_pm_ops, st_thermal_suspend, st_thermal_resume);
EXPORT_SYMBOL_GPL(st_thermal_pm_ops);

MODULE_AUTHOR("STMicroelectronics (R&D) Limited <ajitpal.singh@st.com>");
MODULE_DESCRIPTION("STMicroelectronics STi SoC Thermal Sensor Driver");
MODULE_LICENSE("GPL v2");