root/drivers/power/supply/twl4030_madc_battery.c
// SPDX-License-Identifier: GPL-2.0-only
/*
 * Dumb driver for LiIon batteries using TWL4030 madc.
 *
 * Copyright 2013 Golden Delicious Computers
 * Lukas Märdian <lukas@goldelico.com>
 *
 * Based on dumb driver for gta01 battery
 * Copyright 2009 Openmoko, Inc
 * Balaji Rao <balajirrao@openmoko.org>
 */

#include <linux/module.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/power_supply.h>
#include <linux/slab.h>
#include <linux/sort.h>
#include <linux/power/twl4030_madc_battery.h>
#include <linux/iio/consumer.h>

struct twl4030_madc_battery {
        struct power_supply *psy;
        struct twl4030_madc_bat_platform_data *pdata;
        struct iio_channel *channel_temp;
        struct iio_channel *channel_ichg;
        struct iio_channel *channel_vbat;
};

static enum power_supply_property twl4030_madc_bat_props[] = {
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_CHARGE_FULL,
        POWER_SUPPLY_PROP_CHARGE_NOW,
        POWER_SUPPLY_PROP_TEMP,
        POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW,
};

static int madc_read(struct iio_channel *channel)
{
        int val, err;
        err = iio_read_channel_processed(channel, &val);
        if (err < 0)
                return err;

        return val;
}

static int twl4030_madc_bat_get_charging_status(struct twl4030_madc_battery *bt)
{
        return (madc_read(bt->channel_ichg) > 0) ? 1 : 0;
}

static int twl4030_madc_bat_get_voltage(struct twl4030_madc_battery *bt)
{
        return madc_read(bt->channel_vbat);
}

static int twl4030_madc_bat_get_current(struct twl4030_madc_battery *bt)
{
        return madc_read(bt->channel_ichg) * 1000;
}

static int twl4030_madc_bat_get_temp(struct twl4030_madc_battery *bt)
{
        return madc_read(bt->channel_temp) * 10;
}

static int twl4030_madc_bat_voltscale(struct twl4030_madc_battery *bat,
                                        int volt)
{
        struct twl4030_madc_bat_calibration *calibration;
        int i, res = 0;

        /* choose charging curve */
        if (twl4030_madc_bat_get_charging_status(bat))
                calibration = bat->pdata->charging;
        else
                calibration = bat->pdata->discharging;

        if (volt > calibration[0].voltage) {
                res = calibration[0].level;
        } else {
                for (i = 0; calibration[i+1].voltage >= 0; i++) {
                        if (volt <= calibration[i].voltage &&
                                        volt >= calibration[i+1].voltage) {
                                /* interval found - interpolate within range */
                                res = calibration[i].level -
                                        ((calibration[i].voltage - volt) *
                                        (calibration[i].level -
                                        calibration[i+1].level)) /
                                        (calibration[i].voltage -
                                        calibration[i+1].voltage);
                                break;
                        }
                }
        }
        return res;
}

static int twl4030_madc_bat_get_property(struct power_supply *psy,
                                        enum power_supply_property psp,
                                        union power_supply_propval *val)
{
        struct twl4030_madc_battery *bat = power_supply_get_drvdata(psy);

        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                if (twl4030_madc_bat_voltscale(bat,
                                twl4030_madc_bat_get_voltage(bat)) > 95)
                        val->intval = POWER_SUPPLY_STATUS_FULL;
                else {
                        if (twl4030_madc_bat_get_charging_status(bat))
                                val->intval = POWER_SUPPLY_STATUS_CHARGING;
                        else
                                val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
                }
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
                val->intval = twl4030_madc_bat_get_voltage(bat) * 1000;
                break;
        case POWER_SUPPLY_PROP_TECHNOLOGY:
                val->intval = POWER_SUPPLY_TECHNOLOGY_LION;
                break;
        case POWER_SUPPLY_PROP_CURRENT_NOW:
                val->intval = twl4030_madc_bat_get_current(bat);
                break;
        case POWER_SUPPLY_PROP_PRESENT:
                /* assume battery is always present */
                val->intval = 1;
                break;
        case POWER_SUPPLY_PROP_CHARGE_NOW: {
                        int percent = twl4030_madc_bat_voltscale(bat,
                                        twl4030_madc_bat_get_voltage(bat));
                        val->intval = (percent * bat->pdata->capacity) / 100;
                        break;
                }
        case POWER_SUPPLY_PROP_CAPACITY:
                val->intval = twl4030_madc_bat_voltscale(bat,
                                        twl4030_madc_bat_get_voltage(bat));
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL:
                val->intval = bat->pdata->capacity;
                break;
        case POWER_SUPPLY_PROP_TEMP:
                val->intval = twl4030_madc_bat_get_temp(bat);
                break;
        case POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW: {
                        int percent = twl4030_madc_bat_voltscale(bat,
                                        twl4030_madc_bat_get_voltage(bat));
                        /* in mAh */
                        int chg = (percent * (bat->pdata->capacity/1000))/100;

                        /* assume discharge with 400 mA (ca. 1.5W) */
                        val->intval = (3600l * chg) / 400;
                        break;
                }
        default:
                return -EINVAL;
        }

        return 0;
}

static const struct power_supply_desc twl4030_madc_bat_desc = {
        .name                   = "twl4030_battery",
        .type                   = POWER_SUPPLY_TYPE_BATTERY,
        .properties             = twl4030_madc_bat_props,
        .num_properties         = ARRAY_SIZE(twl4030_madc_bat_props),
        .get_property           = twl4030_madc_bat_get_property,
        .external_power_changed = power_supply_changed,
};

static int twl4030_cmp(const void *a, const void *b)
{
        return ((struct twl4030_madc_bat_calibration *)b)->voltage -
                ((struct twl4030_madc_bat_calibration *)a)->voltage;
}

static int twl4030_madc_battery_probe(struct platform_device *pdev)
{
        struct twl4030_madc_battery *twl4030_madc_bat;
        struct twl4030_madc_bat_platform_data *pdata = pdev->dev.platform_data;
        struct power_supply_config psy_cfg = {};

        twl4030_madc_bat = devm_kzalloc(&pdev->dev, sizeof(*twl4030_madc_bat),
                                GFP_KERNEL);
        if (!twl4030_madc_bat)
                return -ENOMEM;

        twl4030_madc_bat->channel_temp = devm_iio_channel_get(&pdev->dev, "temp");
        if (IS_ERR(twl4030_madc_bat->channel_temp))
                return PTR_ERR(twl4030_madc_bat->channel_temp);

        twl4030_madc_bat->channel_ichg = devm_iio_channel_get(&pdev->dev, "ichg");
        if (IS_ERR(twl4030_madc_bat->channel_ichg))
                return PTR_ERR(twl4030_madc_bat->channel_ichg);

        twl4030_madc_bat->channel_vbat = devm_iio_channel_get(&pdev->dev, "vbat");
        if (IS_ERR(twl4030_madc_bat->channel_vbat))
                return PTR_ERR(twl4030_madc_bat->channel_vbat);

        /* sort charging and discharging calibration data */
        sort(pdata->charging, pdata->charging_size,
                sizeof(struct twl4030_madc_bat_calibration),
                twl4030_cmp, NULL);
        sort(pdata->discharging, pdata->discharging_size,
                sizeof(struct twl4030_madc_bat_calibration),
                twl4030_cmp, NULL);

        twl4030_madc_bat->pdata = pdata;
        psy_cfg.drv_data = twl4030_madc_bat;
        twl4030_madc_bat->psy = devm_power_supply_register(&pdev->dev,
                                                           &twl4030_madc_bat_desc,
                                                           &psy_cfg);
        if (IS_ERR(twl4030_madc_bat->psy))
                return PTR_ERR(twl4030_madc_bat->psy);

        return 0;
}

static struct platform_driver twl4030_madc_battery_driver = {
        .driver = {
                .name = "twl4030_madc_battery",
        },
        .probe  = twl4030_madc_battery_probe,
};
module_platform_driver(twl4030_madc_battery_driver);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Lukas Märdian <lukas@goldelico.com>");
MODULE_DESCRIPTION("twl4030_madc battery driver");
MODULE_ALIAS("platform:twl4030_madc_battery");