/*
 * DA9150 Fuel-Gauge Driver
 *
 * Copyright (c) 2015 Dialog Semiconductor
 *
 * Author: Adam Thomson <Adam.Thomson.Opensource@diasemi.com>
 *
 * 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/kernel.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/of.h>
#include <linux/of_platform.h>
#include <linux/slab.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/power_supply.h>
#include <linux/list.h>
#include <asm/div64.h>
#include <linux/mfd/da9150/core.h>
#include <linux/mfd/da9150/registers.h>

/* Core2Wire */
#define DA9150_QIF_READ         (0x0 << 7)
#define DA9150_QIF_WRITE        (0x1 << 7)
#define DA9150_QIF_CODE_MASK    0x7F

#define DA9150_QIF_BYTE_SIZE    8
#define DA9150_QIF_BYTE_MASK    0xFF
#define DA9150_QIF_SHORT_SIZE   2
#define DA9150_QIF_LONG_SIZE    4

/* QIF Codes */
#define DA9150_QIF_UAVG                 6
#define DA9150_QIF_UAVG_SIZE            DA9150_QIF_LONG_SIZE
#define DA9150_QIF_IAVG                 8
#define DA9150_QIF_IAVG_SIZE            DA9150_QIF_LONG_SIZE
#define DA9150_QIF_NTCAVG               12
#define DA9150_QIF_NTCAVG_SIZE          DA9150_QIF_LONG_SIZE
#define DA9150_QIF_SHUNT_VAL            36
#define DA9150_QIF_SHUNT_VAL_SIZE       DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_SD_GAIN              38
#define DA9150_QIF_SD_GAIN_SIZE         DA9150_QIF_LONG_SIZE
#define DA9150_QIF_FCC_MAH              40
#define DA9150_QIF_FCC_MAH_SIZE         DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_SOC_PCT              43
#define DA9150_QIF_SOC_PCT_SIZE         DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_CHARGE_LIMIT         44
#define DA9150_QIF_CHARGE_LIMIT_SIZE    DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_DISCHARGE_LIMIT      45
#define DA9150_QIF_DISCHARGE_LIMIT_SIZE DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_FW_MAIN_VER          118
#define DA9150_QIF_FW_MAIN_VER_SIZE     DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_E_FG_STATUS          126
#define DA9150_QIF_E_FG_STATUS_SIZE     DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_SYNC                 127
#define DA9150_QIF_SYNC_SIZE            DA9150_QIF_SHORT_SIZE
#define DA9150_QIF_MAX_CODES            128

/* QIF Sync Timeout */
#define DA9150_QIF_SYNC_TIMEOUT         1000
#define DA9150_QIF_SYNC_RETRIES         10

/* QIF E_FG_STATUS */
#define DA9150_FG_IRQ_LOW_SOC_MASK      (1 << 0)
#define DA9150_FG_IRQ_HIGH_SOC_MASK     (1 << 1)
#define DA9150_FG_IRQ_SOC_MASK  \
        (DA9150_FG_IRQ_LOW_SOC_MASK | DA9150_FG_IRQ_HIGH_SOC_MASK)

/* Private data */
struct da9150_fg {
        struct da9150 *da9150;
        struct device *dev;

        struct mutex io_lock;

        struct power_supply *battery;
        struct delayed_work work;
        u32 interval;

        int warn_soc;
        int crit_soc;
        int soc;
};

/* Battery Properties */
static u32 da9150_fg_read_attr(struct da9150_fg *fg, u8 code, u8 size)

{
        u8 buf[size];
        u8 read_addr;
        u32 res = 0;
        int i;

        /* Set QIF code (READ mode) */
        read_addr = (code & DA9150_QIF_CODE_MASK) | DA9150_QIF_READ;

        da9150_read_qif(fg->da9150, read_addr, size, buf);
        for (i = 0; i < size; ++i)
                res |= (buf[i] << (i * DA9150_QIF_BYTE_SIZE));

        return res;
}

static void da9150_fg_write_attr(struct da9150_fg *fg, u8 code, u8 size,
                                 u32 val)

{
        u8 buf[size];
        u8 write_addr;
        int i;

        /* Set QIF code (WRITE mode) */
        write_addr = (code & DA9150_QIF_CODE_MASK) | DA9150_QIF_WRITE;

        for (i = 0; i < size; ++i) {
                buf[i] = (val >> (i * DA9150_QIF_BYTE_SIZE)) &
                         DA9150_QIF_BYTE_MASK;
        }
        da9150_write_qif(fg->da9150, write_addr, size, buf);
}

/* Trigger QIF Sync to update QIF readable data */
static void da9150_fg_read_sync_start(struct da9150_fg *fg)
{
        int i = 0;
        u32 res = 0;

        mutex_lock(&fg->io_lock);

        /* Check if QIF sync already requested, and write to sync if not */
        res = da9150_fg_read_attr(fg, DA9150_QIF_SYNC,
                                  DA9150_QIF_SYNC_SIZE);
        if (res > 0)
                da9150_fg_write_attr(fg, DA9150_QIF_SYNC,
                                     DA9150_QIF_SYNC_SIZE, 0);

        /* Wait for sync to complete */
        res = 0;
        while ((res == 0) && (i++ < DA9150_QIF_SYNC_RETRIES)) {
                usleep_range(DA9150_QIF_SYNC_TIMEOUT,
                             DA9150_QIF_SYNC_TIMEOUT * 2);
                res = da9150_fg_read_attr(fg, DA9150_QIF_SYNC,
                                          DA9150_QIF_SYNC_SIZE);
        }

        /* Check if sync completed */
        if (res == 0)
                dev_err(fg->dev, "Failed to perform QIF read sync!\n");
}

/*
 * Should always be called after QIF sync read has been performed, and all
 * attributes required have been accessed.
 */
static inline void da9150_fg_read_sync_end(struct da9150_fg *fg)
{
        mutex_unlock(&fg->io_lock);
}

/* Sync read of single QIF attribute */
static u32 da9150_fg_read_attr_sync(struct da9150_fg *fg, u8 code, u8 size)
{
        u32 val;

        da9150_fg_read_sync_start(fg);
        val = da9150_fg_read_attr(fg, code, size);
        da9150_fg_read_sync_end(fg);

        return val;
}

/* Wait for QIF Sync, write QIF data and wait for ack */
static void da9150_fg_write_attr_sync(struct da9150_fg *fg, u8 code, u8 size,
                                      u32 val)
{
        int i = 0;
        u32 res = 0, sync_val;

        mutex_lock(&fg->io_lock);

        /* Check if QIF sync already requested */
        res = da9150_fg_read_attr(fg, DA9150_QIF_SYNC,
                                  DA9150_QIF_SYNC_SIZE);

        /* Wait for an existing sync to complete */
        while ((res == 0) && (i++ < DA9150_QIF_SYNC_RETRIES)) {
                usleep_range(DA9150_QIF_SYNC_TIMEOUT,
                             DA9150_QIF_SYNC_TIMEOUT * 2);
                res = da9150_fg_read_attr(fg, DA9150_QIF_SYNC,
                                          DA9150_QIF_SYNC_SIZE);
        }

        if (res == 0) {
                dev_err(fg->dev, "Timeout waiting for existing QIF sync!\n");
                mutex_unlock(&fg->io_lock);
                return;
        }

        /* Write value for QIF code */
        da9150_fg_write_attr(fg, code, size, val);

        /* Wait for write acknowledgment */
        i = 0;
        sync_val = res;
        while ((res == sync_val) && (i++ < DA9150_QIF_SYNC_RETRIES)) {
                usleep_range(DA9150_QIF_SYNC_TIMEOUT,
                             DA9150_QIF_SYNC_TIMEOUT * 2);
                res = da9150_fg_read_attr(fg, DA9150_QIF_SYNC,
                                          DA9150_QIF_SYNC_SIZE);
        }

        mutex_unlock(&fg->io_lock);

        /* Check write was actually successful */
        if (res != (sync_val + 1))
                dev_err(fg->dev, "Error performing QIF sync write for code %d\n",
                        code);
}

/* Power Supply attributes */
static int da9150_fg_capacity(struct da9150_fg *fg,
                              union power_supply_propval *val)
{
        val->intval = da9150_fg_read_attr_sync(fg, DA9150_QIF_SOC_PCT,
                                               DA9150_QIF_SOC_PCT_SIZE);

        if (val->intval > 100)
                val->intval = 100;

        return 0;
}

static int da9150_fg_current_avg(struct da9150_fg *fg,
                                 union power_supply_propval *val)
{
        u32 iavg, sd_gain, shunt_val;
        u64 div, res;

        da9150_fg_read_sync_start(fg);
        iavg = da9150_fg_read_attr(fg, DA9150_QIF_IAVG,
                                   DA9150_QIF_IAVG_SIZE);
        shunt_val = da9150_fg_read_attr(fg, DA9150_QIF_SHUNT_VAL,
                                        DA9150_QIF_SHUNT_VAL_SIZE);
        sd_gain = da9150_fg_read_attr(fg, DA9150_QIF_SD_GAIN,
                                      DA9150_QIF_SD_GAIN_SIZE);
        da9150_fg_read_sync_end(fg);

        div = (u64) (sd_gain * shunt_val * 65536ULL);
        do_div(div, 1000000);
        res = (u64) (iavg * 1000000ULL);
        do_div(res, div);

        val->intval = (int) res;

        return 0;
}

static int da9150_fg_voltage_avg(struct da9150_fg *fg,
                                 union power_supply_propval *val)
{
        u64 res;

        val->intval = da9150_fg_read_attr_sync(fg, DA9150_QIF_UAVG,
                                               DA9150_QIF_UAVG_SIZE);

        res = (u64) (val->intval * 186ULL);
        do_div(res, 10000);
        val->intval = (int) res;

        return 0;
}

static int da9150_fg_charge_full(struct da9150_fg *fg,
                                 union power_supply_propval *val)
{
        val->intval = da9150_fg_read_attr_sync(fg, DA9150_QIF_FCC_MAH,
                                               DA9150_QIF_FCC_MAH_SIZE);

        val->intval = val->intval * 1000;

        return 0;
}

/*
 * Temperature reading from device is only valid if battery/system provides
 * valid NTC to associated pin of DA9150 chip.
 */
static int da9150_fg_temp(struct da9150_fg *fg,
                          union power_supply_propval *val)
{
        val->intval = da9150_fg_read_attr_sync(fg, DA9150_QIF_NTCAVG,
                                               DA9150_QIF_NTCAVG_SIZE);

        val->intval = (val->intval * 10) / 1048576;

        return 0;
}

static enum power_supply_property da9150_fg_props[] = {
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_CURRENT_AVG,
        POWER_SUPPLY_PROP_VOLTAGE_AVG,
        POWER_SUPPLY_PROP_CHARGE_FULL,
        POWER_SUPPLY_PROP_TEMP,
};

static int da9150_fg_get_prop(struct power_supply *psy,
                              enum power_supply_property psp,
                              union power_supply_propval *val)
{
        struct da9150_fg *fg = dev_get_drvdata(psy->dev.parent);
        int ret;

        switch (psp) {
        case POWER_SUPPLY_PROP_CAPACITY:
                ret = da9150_fg_capacity(fg, val);
                break;
        case POWER_SUPPLY_PROP_CURRENT_AVG:
                ret = da9150_fg_current_avg(fg, val);
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_AVG:
                ret = da9150_fg_voltage_avg(fg, val);
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL:
                ret = da9150_fg_charge_full(fg, val);
                break;
        case POWER_SUPPLY_PROP_TEMP:
                ret = da9150_fg_temp(fg, val);
                break;
        default:
                ret = -EINVAL;
                break;
        }

        return ret;
}

/* Repeated SOC check */
static bool da9150_fg_soc_changed(struct da9150_fg *fg)
{
        union power_supply_propval val;

        da9150_fg_capacity(fg, &val);
        if (val.intval != fg->soc) {
                fg->soc = val.intval;
                return true;
        }

        return false;
}

static void da9150_fg_work(struct work_struct *work)
{
        struct da9150_fg *fg = container_of(work, struct da9150_fg, work.work);

        /* Report if SOC has changed */
        if (da9150_fg_soc_changed(fg))
                power_supply_changed(fg->battery);

        schedule_delayed_work(&fg->work, msecs_to_jiffies(fg->interval));
}

/* SOC level event configuration */
static void da9150_fg_soc_event_config(struct da9150_fg *fg)
{
        int soc;

        soc = da9150_fg_read_attr_sync(fg, DA9150_QIF_SOC_PCT,
                                       DA9150_QIF_SOC_PCT_SIZE);

        if (soc > fg->warn_soc) {
                /* If SOC > warn level, set discharge warn level event */
                da9150_fg_write_attr_sync(fg, DA9150_QIF_DISCHARGE_LIMIT,
                                          DA9150_QIF_DISCHARGE_LIMIT_SIZE,
                                          fg->warn_soc + 1);
        } else if ((soc <= fg->warn_soc) && (soc > fg->crit_soc)) {
                /*
                 * If SOC <= warn level, set discharge crit level event,
                 * and set charge warn level event.
                 */
                da9150_fg_write_attr_sync(fg, DA9150_QIF_DISCHARGE_LIMIT,
                                          DA9150_QIF_DISCHARGE_LIMIT_SIZE,
                                          fg->crit_soc + 1);

                da9150_fg_write_attr_sync(fg, DA9150_QIF_CHARGE_LIMIT,
                                          DA9150_QIF_CHARGE_LIMIT_SIZE,
                                          fg->warn_soc);
        } else if (soc <= fg->crit_soc) {
                /* If SOC <= crit level, set charge crit level event */
                da9150_fg_write_attr_sync(fg, DA9150_QIF_CHARGE_LIMIT,
                                          DA9150_QIF_CHARGE_LIMIT_SIZE,
                                          fg->crit_soc);
        }
}

static irqreturn_t da9150_fg_irq(int irq, void *data)
{
        struct da9150_fg *fg = data;
        u32 e_fg_status;

        /* Read FG IRQ status info */
        e_fg_status = da9150_fg_read_attr(fg, DA9150_QIF_E_FG_STATUS,
                                          DA9150_QIF_E_FG_STATUS_SIZE);

        /* Handle warning/critical threhold events */
        if (e_fg_status & DA9150_FG_IRQ_SOC_MASK)
                da9150_fg_soc_event_config(fg);

        /* Clear any FG IRQs */
        da9150_fg_write_attr(fg, DA9150_QIF_E_FG_STATUS,
                             DA9150_QIF_E_FG_STATUS_SIZE, e_fg_status);

        return IRQ_HANDLED;
}

static struct da9150_fg_pdata *da9150_fg_dt_pdata(struct device *dev)
{
        struct device_node *fg_node = dev->of_node;
        struct da9150_fg_pdata *pdata;

        pdata = devm_kzalloc(dev, sizeof(struct da9150_fg_pdata), GFP_KERNEL);
        if (!pdata)
                return NULL;

        of_property_read_u32(fg_node, "dlg,update-interval",
                             &pdata->update_interval);
        of_property_read_u8(fg_node, "dlg,warn-soc-level",
                            &pdata->warn_soc_lvl);
        of_property_read_u8(fg_node, "dlg,crit-soc-level",
                            &pdata->crit_soc_lvl);

        return pdata;
}

static const struct power_supply_desc fg_desc = {
        .name           = "da9150-fg",
        .type           = POWER_SUPPLY_TYPE_BATTERY,
        .properties     = da9150_fg_props,
        .num_properties = ARRAY_SIZE(da9150_fg_props),
        .get_property   = da9150_fg_get_prop,
};

static int da9150_fg_probe(struct platform_device *pdev)
{
        struct device *dev = &pdev->dev;
        struct da9150 *da9150 = dev_get_drvdata(dev->parent);
        struct da9150_fg_pdata *fg_pdata = dev_get_platdata(dev);
        struct da9150_fg *fg;
        int ver, irq, ret = 0;

        fg = devm_kzalloc(dev, sizeof(*fg), GFP_KERNEL);
        if (fg == NULL)
                return -ENOMEM;

        platform_set_drvdata(pdev, fg);
        fg->da9150 = da9150;
        fg->dev = dev;

        mutex_init(&fg->io_lock);

        /* Enable QIF */
        da9150_set_bits(da9150, DA9150_CORE2WIRE_CTRL_A, DA9150_FG_QIF_EN_MASK,
                        DA9150_FG_QIF_EN_MASK);

        fg->battery = devm_power_supply_register(dev, &fg_desc, NULL);
        if (IS_ERR(fg->battery)) {
                ret = PTR_ERR(fg->battery);
                return ret;
        }

        ver = da9150_fg_read_attr(fg, DA9150_QIF_FW_MAIN_VER,
                                  DA9150_QIF_FW_MAIN_VER_SIZE);
        dev_info(dev, "Version: 0x%x\n", ver);

        /* Handle DT data if provided */
        if (dev->of_node) {
                fg_pdata = da9150_fg_dt_pdata(dev);
                dev->platform_data = fg_pdata;
        }

        /* Handle any pdata provided */
        if (fg_pdata) {
                fg->interval = fg_pdata->update_interval;

                if (fg_pdata->warn_soc_lvl > 100)
                        dev_warn(dev, "Invalid SOC warning level provided, Ignoring");
                else
                        fg->warn_soc = fg_pdata->warn_soc_lvl;

                if ((fg_pdata->crit_soc_lvl > 100) ||
                    (fg_pdata->crit_soc_lvl >= fg_pdata->warn_soc_lvl))
                        dev_warn(dev, "Invalid SOC critical level provided, Ignoring");
                else
                        fg->crit_soc = fg_pdata->crit_soc_lvl;


        }

        /* Configure initial SOC level events */
        da9150_fg_soc_event_config(fg);

        /*
         * If an interval period has been provided then setup repeating
         * work for reporting data updates.
         */
        if (fg->interval) {
                INIT_DELAYED_WORK(&fg->work, da9150_fg_work);
                schedule_delayed_work(&fg->work,
                                      msecs_to_jiffies(fg->interval));
        }

        /* Register IRQ */
        irq = platform_get_irq_byname(pdev, "FG");
        if (irq < 0) {
                dev_err(dev, "Failed to get IRQ FG: %d\n", irq);
                ret = irq;
                goto irq_fail;
        }

        ret = devm_request_threaded_irq(dev, irq, NULL, da9150_fg_irq,
                                        IRQF_ONESHOT, "FG", fg);
        if (ret) {
                dev_err(dev, "Failed to request IRQ %d: %d\n", irq, ret);
                goto irq_fail;
        }

        return 0;

irq_fail:
        if (fg->interval)
                cancel_delayed_work(&fg->work);

        return ret;
}

static int da9150_fg_remove(struct platform_device *pdev)
{
        struct da9150_fg *fg = platform_get_drvdata(pdev);

        if (fg->interval)
                cancel_delayed_work(&fg->work);

        return 0;
}

static int da9150_fg_resume(struct platform_device *pdev)
{
        struct da9150_fg *fg = platform_get_drvdata(pdev);

        /*
         * Trigger SOC check to happen now so as to indicate any value change
         * since last check before suspend.
         */
        if (fg->interval)
                flush_delayed_work(&fg->work);

        return 0;
}

static struct platform_driver da9150_fg_driver = {
        .driver = {
                .name = "da9150-fuel-gauge",
        },
        .probe = da9150_fg_probe,
        .remove = da9150_fg_remove,
        .resume = da9150_fg_resume,
};

module_platform_driver(da9150_fg_driver);

MODULE_DESCRIPTION("Fuel-Gauge Driver for DA9150");
MODULE_AUTHOR("Adam Thomson <Adam.Thomson.Opensource@diasemi.com>");
MODULE_LICENSE("GPL");