/*
 * Copyright (c) 2011-2015, The Linux Foundation. All rights reserved.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 and
 * only 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.
 */

#include <linux/delay.h>
#include <linux/err.h>
#include <linux/iio/consumer.h>
#include <linux/interrupt.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/thermal.h>

#define QPNP_TM_REG_TYPE                0x04
#define QPNP_TM_REG_SUBTYPE             0x05
#define QPNP_TM_REG_STATUS              0x08
#define QPNP_TM_REG_SHUTDOWN_CTRL1      0x40
#define QPNP_TM_REG_ALARM_CTRL          0x46

#define QPNP_TM_TYPE                    0x09
#define QPNP_TM_SUBTYPE                 0x08

#define STATUS_STAGE_MASK               0x03

#define SHUTDOWN_CTRL1_THRESHOLD_MASK   0x03

#define ALARM_CTRL_FORCE_ENABLE         0x80

/*
 * Trip point values based on threshold control
 * 0 = {105 C, 125 C, 145 C}
 * 1 = {110 C, 130 C, 150 C}
 * 2 = {115 C, 135 C, 155 C}
 * 3 = {120 C, 140 C, 160 C}
*/
#define TEMP_STAGE_STEP                 20000   /* Stage step: 20.000 C */
#define TEMP_STAGE_HYSTERESIS           2000

#define TEMP_THRESH_MIN                 105000  /* Threshold Min: 105 C */
#define TEMP_THRESH_STEP                5000    /* Threshold step: 5 C */

#define THRESH_MIN                      0

/* Temperature in Milli Celsius reported during stage 0 if no ADC is present */
#define DEFAULT_TEMP                    37000

struct qpnp_tm_chip {
        struct regmap                   *map;
        struct thermal_zone_device      *tz_dev;
        long                            temp;
        unsigned int                    thresh;
        unsigned int                    stage;
        unsigned int                    prev_stage;
        unsigned int                    base;
        struct iio_channel              *adc;
};

static int qpnp_tm_read(struct qpnp_tm_chip *chip, u16 addr, u8 *data)
{
        unsigned int val;
        int ret;

        ret = regmap_read(chip->map, chip->base + addr, &val);
        if (ret < 0)
                return ret;

        *data = val;
        return 0;
}

static int qpnp_tm_write(struct qpnp_tm_chip *chip, u16 addr, u8 data)
{
        return regmap_write(chip->map, chip->base + addr, data);
}

/*
 * This function updates the internal temp value based on the
 * current thermal stage and threshold as well as the previous stage
 */
static int qpnp_tm_update_temp_no_adc(struct qpnp_tm_chip *chip)
{
        unsigned int stage;
        int ret;
        u8 reg = 0;

        ret = qpnp_tm_read(chip, QPNP_TM_REG_STATUS, &reg);
        if (ret < 0)
                return ret;

        stage = reg & STATUS_STAGE_MASK;

        if (stage > chip->stage) {
                /* increasing stage, use lower bound */
                chip->temp = (stage - 1) * TEMP_STAGE_STEP +
                             chip->thresh * TEMP_THRESH_STEP +
                             TEMP_STAGE_HYSTERESIS + TEMP_THRESH_MIN;
        } else if (stage < chip->stage) {
                /* decreasing stage, use upper bound */
                chip->temp = stage * TEMP_STAGE_STEP +
                             chip->thresh * TEMP_THRESH_STEP -
                             TEMP_STAGE_HYSTERESIS + TEMP_THRESH_MIN;
        }

        chip->stage = stage;

        return 0;
}

static int qpnp_tm_get_temp(void *data, int *temp)
{
        struct qpnp_tm_chip *chip = data;
        int ret, mili_celsius;

        if (!temp)
                return -EINVAL;

        if (IS_ERR(chip->adc)) {
                ret = qpnp_tm_update_temp_no_adc(chip);
                if (ret < 0)
                        return ret;
        } else {
                ret = iio_read_channel_processed(chip->adc, &mili_celsius);
                if (ret < 0)
                        return ret;

                chip->temp = mili_celsius;
        }

        *temp = chip->temp < 0 ? 0 : chip->temp;

        return 0;
}

static const struct thermal_zone_of_device_ops qpnp_tm_sensor_ops = {
        .get_temp = qpnp_tm_get_temp,
};

static irqreturn_t qpnp_tm_isr(int irq, void *data)
{
        struct qpnp_tm_chip *chip = data;

        thermal_zone_device_update(chip->tz_dev);

        return IRQ_HANDLED;
}

/*
 * This function initializes the internal temp value based on only the
 * current thermal stage and threshold. Setup threshold control and
 * disable shutdown override.
 */
static int qpnp_tm_init(struct qpnp_tm_chip *chip)
{
        int ret;
        u8 reg;

        chip->thresh = THRESH_MIN;
        chip->temp = DEFAULT_TEMP;

        ret = qpnp_tm_read(chip, QPNP_TM_REG_STATUS, &reg);
        if (ret < 0)
                return ret;

        chip->stage = reg & STATUS_STAGE_MASK;

        if (chip->stage)
                chip->temp = chip->thresh * TEMP_THRESH_STEP +
                             (chip->stage - 1) * TEMP_STAGE_STEP +
                             TEMP_THRESH_MIN;

        /*
         * Set threshold and disable software override of stage 2 and 3
         * shutdowns.
         */
        reg = chip->thresh & SHUTDOWN_CTRL1_THRESHOLD_MASK;
        ret = qpnp_tm_write(chip, QPNP_TM_REG_SHUTDOWN_CTRL1, reg);
        if (ret < 0)
                return ret;

        /* Enable the thermal alarm PMIC module in always-on mode. */
        reg = ALARM_CTRL_FORCE_ENABLE;
        ret = qpnp_tm_write(chip, QPNP_TM_REG_ALARM_CTRL, reg);

        return ret;
}

static int qpnp_tm_probe(struct platform_device *pdev)
{
        struct qpnp_tm_chip *chip;
        struct device_node *node;
        u8 type, subtype;
        u32 res[2];
        int ret, irq;

        node = pdev->dev.of_node;

        chip = devm_kzalloc(&pdev->dev, sizeof(*chip), GFP_KERNEL);
        if (!chip)
                return -ENOMEM;

        dev_set_drvdata(&pdev->dev, chip);

        chip->map = dev_get_regmap(pdev->dev.parent, NULL);
        if (!chip->map)
                return -ENXIO;

        ret = of_property_read_u32_array(node, "reg", res, 2);
        if (ret < 0)
                return ret;

        irq = platform_get_irq(pdev, 0);
        if (irq < 0)
                return irq;

        /* ADC based measurements are optional */
        chip->adc = iio_channel_get(&pdev->dev, "thermal");
        if (PTR_ERR(chip->adc) == -EPROBE_DEFER)
                return PTR_ERR(chip->adc);

        chip->base = res[0];

        ret = qpnp_tm_read(chip, QPNP_TM_REG_TYPE, &type);
        if (ret < 0) {
                dev_err(&pdev->dev, "could not read type\n");
                goto fail;
        }

        ret = qpnp_tm_read(chip, QPNP_TM_REG_SUBTYPE, &subtype);
        if (ret < 0) {
                dev_err(&pdev->dev, "could not read subtype\n");
                goto fail;
        }

        if (type != QPNP_TM_TYPE || subtype != QPNP_TM_SUBTYPE) {
                dev_err(&pdev->dev, "invalid type 0x%02x or subtype 0x%02x\n",
                        type, subtype);
                ret = -ENODEV;
                goto fail;
        }

        ret = qpnp_tm_init(chip);
        if (ret < 0) {
                dev_err(&pdev->dev, "init failed\n");
                goto fail;
        }

        ret = devm_request_threaded_irq(&pdev->dev, irq, NULL, qpnp_tm_isr,
                                        IRQF_ONESHOT, node->name, chip);
        if (ret < 0)
                goto fail;

        chip->tz_dev = thermal_zone_of_sensor_register(&pdev->dev, 0, chip,
                                                        &qpnp_tm_sensor_ops);
        if (IS_ERR(chip->tz_dev)) {
                dev_err(&pdev->dev, "failed to register sensor\n");
                ret = PTR_ERR(chip->tz_dev);
                goto fail;
        }

        return 0;

fail:
        if (!IS_ERR(chip->adc))
                iio_channel_release(chip->adc);

        return ret;
}

static int qpnp_tm_remove(struct platform_device *pdev)
{
        struct qpnp_tm_chip *chip = dev_get_drvdata(&pdev->dev);

        thermal_zone_of_sensor_unregister(&pdev->dev, chip->tz_dev);
        if (!IS_ERR(chip->adc))
                iio_channel_release(chip->adc);

        return 0;
}

static const struct of_device_id qpnp_tm_match_table[] = {
        { .compatible = "qcom,spmi-temp-alarm" },
        { }
};
MODULE_DEVICE_TABLE(of, qpnp_tm_match_table);

static struct platform_driver qpnp_tm_driver = {
        .driver = {
                .name = "spmi-temp-alarm",
                .of_match_table = qpnp_tm_match_table,
        },
        .probe  = qpnp_tm_probe,
        .remove = qpnp_tm_remove,
};
module_platform_driver(qpnp_tm_driver);

MODULE_ALIAS("platform:spmi-temp-alarm");
MODULE_DESCRIPTION("QPNP PMIC Temperature Alarm driver");
MODULE_LICENSE("GPL v2");