// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  battery.c - ACPI Battery Driver (Revision: 2.0)
 *
 *  Copyright (C) 2007 Alexey Starikovskiy <astarikovskiy@suse.de>
 *  Copyright (C) 2004-2007 Vladimir Lebedev <vladimir.p.lebedev@intel.com>
 *  Copyright (C) 2001, 2002 Andy Grover <andrew.grover@intel.com>
 *  Copyright (C) 2001, 2002 Paul Diefenbaugh <paul.s.diefenbaugh@intel.com>
 */

#define pr_fmt(fmt) "ACPI: battery: " fmt

#include <linux/delay.h>
#include <linux/dmi.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/suspend.h>
#include <linux/types.h>

#include <linux/unaligned.h>

#include <linux/acpi.h>
#include <linux/power_supply.h>

#include <acpi/battery.h>

#define ACPI_BATTERY_VALUE_UNKNOWN 0xFFFFFFFF
#define ACPI_BATTERY_CAPACITY_VALID(capacity) \
        ((capacity) != 0 && (capacity) != ACPI_BATTERY_VALUE_UNKNOWN)

#define ACPI_BATTERY_DEVICE_NAME        "Battery"

/* Battery power unit: 0 means mW, 1 means mA */
#define ACPI_BATTERY_POWER_UNIT_MA      1

#define ACPI_BATTERY_STATE_DISCHARGING          0x1
#define ACPI_BATTERY_STATE_CHARGING             0x2
#define ACPI_BATTERY_STATE_CRITICAL             0x4
#define ACPI_BATTERY_STATE_CHARGE_LIMITING      0x8

#define MAX_STRING_LENGTH       64

MODULE_AUTHOR("Paul Diefenbaugh");
MODULE_AUTHOR("Alexey Starikovskiy <astarikovskiy@suse.de>");
MODULE_DESCRIPTION("ACPI Battery Driver");
MODULE_LICENSE("GPL");

static int battery_bix_broken_package;
static int battery_notification_delay_ms;
static int battery_ac_is_broken;
static unsigned int cache_time = 1000;
module_param(cache_time, uint, 0644);
MODULE_PARM_DESC(cache_time, "cache time in milliseconds");

static const struct acpi_device_id battery_device_ids[] = {
        {"PNP0C0A", 0},

        /* Microsoft Surface Go 3 */
        {"MSHW0146", 0},

        {"", 0},
};

MODULE_DEVICE_TABLE(acpi, battery_device_ids);

enum {
        ACPI_BATTERY_ALARM_PRESENT,
        ACPI_BATTERY_XINFO_PRESENT,
        ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY,
        /* On Lenovo Thinkpad models from 2010 and 2011, the power unit
         * switches between mWh and mAh depending on whether the system
         * is running on battery or not.  When mAh is the unit, most
         * reported values are incorrect and need to be adjusted by
         * 10000/design_voltage.  Verified on x201, t410, t410s, and x220.
         * Pre-2010 and 2012 models appear to always report in mWh and
         * are thus unaffected (tested with t42, t61, t500, x200, x300,
         * and x230).  Also, in mid-2012 Lenovo issued a BIOS update for
         *  the 2011 models that fixes the issue (tested on x220 with a
         * post-1.29 BIOS), but as of Nov. 2012, no such update is
         * available for the 2010 models.
         */
        ACPI_BATTERY_QUIRK_THINKPAD_MAH,
        /* for batteries reporting current capacity with design capacity
         * on a full charge, but showing degradation in full charge cap.
         */
        ACPI_BATTERY_QUIRK_DEGRADED_FULL_CHARGE,
};

struct acpi_battery {
        struct mutex update_lock;
        struct power_supply *bat;
        struct power_supply_desc bat_desc;
        struct acpi_device *device;
        struct notifier_block pm_nb;
        struct list_head list;
        unsigned long update_time;
        int revision;
        int rate_now;
        int capacity_now;
        int voltage_now;
        int design_capacity;
        int full_charge_capacity;
        int technology;
        int design_voltage;
        int design_capacity_warning;
        int design_capacity_low;
        int cycle_count;
        int measurement_accuracy;
        int max_sampling_time;
        int min_sampling_time;
        int max_averaging_interval;
        int min_averaging_interval;
        int capacity_granularity_1;
        int capacity_granularity_2;
        int alarm;
        char model_number[MAX_STRING_LENGTH];
        char serial_number[MAX_STRING_LENGTH];
        char type[MAX_STRING_LENGTH];
        char oem_info[MAX_STRING_LENGTH];
        int state;
        int power_unit;
        unsigned long flags;
};

#define to_acpi_battery(x) power_supply_get_drvdata(x)

static inline int acpi_battery_present(struct acpi_battery *battery)
{
        return battery->device->status.battery_present;
}

static int acpi_battery_technology(struct acpi_battery *battery)
{
        if (!strcasecmp("NiCd", battery->type))
                return POWER_SUPPLY_TECHNOLOGY_NiCd;
        if (!strcasecmp("NiMH", battery->type))
                return POWER_SUPPLY_TECHNOLOGY_NiMH;
        if (!strcasecmp("LION", battery->type))
                return POWER_SUPPLY_TECHNOLOGY_LION;
        if (!strncasecmp("LI-ION", battery->type, 6))
                return POWER_SUPPLY_TECHNOLOGY_LION;
        if (!strcasecmp("LiP", battery->type))
                return POWER_SUPPLY_TECHNOLOGY_LIPO;
        return POWER_SUPPLY_TECHNOLOGY_UNKNOWN;
}

static int acpi_battery_get_state(struct acpi_battery *battery);

static int acpi_battery_is_charged(struct acpi_battery *battery)
{
        /* charging, discharging, critical low or charge limited */
        if (battery->state != 0)
                return 0;

        /* battery not reporting charge */
        if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN ||
            battery->capacity_now == 0)
                return 0;

        /* good batteries update full_charge as the batteries degrade */
        if (battery->full_charge_capacity == battery->capacity_now)
                return 1;

        /* fallback to using design values for broken batteries */
        if (battery->design_capacity <= battery->capacity_now)
                return 1;

        /* we don't do any sort of metric based on percentages */
        return 0;
}

static bool acpi_battery_is_degraded(struct acpi_battery *battery)
{
        return ACPI_BATTERY_CAPACITY_VALID(battery->full_charge_capacity) &&
                ACPI_BATTERY_CAPACITY_VALID(battery->design_capacity) &&
                battery->full_charge_capacity < battery->design_capacity;
}

static int acpi_battery_handle_discharging(struct acpi_battery *battery)
{
        /*
         * Some devices wrongly report discharging if the battery's charge level
         * was above the device's start charging threshold atm the AC adapter
         * was plugged in and the device thus did not start a new charge cycle.
         */
        if ((battery_ac_is_broken || power_supply_is_system_supplied()) &&
            battery->rate_now == 0)
                return POWER_SUPPLY_STATUS_NOT_CHARGING;

        return POWER_SUPPLY_STATUS_DISCHARGING;
}

static int acpi_battery_get_property(struct power_supply *psy,
                                     enum power_supply_property psp,
                                     union power_supply_propval *val)
{
        int full_capacity = ACPI_BATTERY_VALUE_UNKNOWN, ret = 0;
        struct acpi_battery *battery = to_acpi_battery(psy);

        if (acpi_battery_present(battery)) {
                /* run battery update only if it is present */
                acpi_battery_get_state(battery);
        } else if (psp != POWER_SUPPLY_PROP_PRESENT)
                return -ENODEV;
        switch (psp) {
        case POWER_SUPPLY_PROP_STATUS:
                if (battery->state & ACPI_BATTERY_STATE_DISCHARGING)
                        val->intval = acpi_battery_handle_discharging(battery);
                else if (battery->state & ACPI_BATTERY_STATE_CHARGING)
                        /* Validate the status by checking the current. */
                        if (battery->rate_now != ACPI_BATTERY_VALUE_UNKNOWN &&
                            battery->rate_now == 0) {
                                /* On charge but no current (0W/0mA). */
                                val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                        } else {
                                val->intval = POWER_SUPPLY_STATUS_CHARGING;
                        }
                else if (battery->state & ACPI_BATTERY_STATE_CHARGE_LIMITING)
                        val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                else if (acpi_battery_is_charged(battery))
                        val->intval = POWER_SUPPLY_STATUS_FULL;
                else
                        val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
                break;
        case POWER_SUPPLY_PROP_PRESENT:
                val->intval = acpi_battery_present(battery);
                break;
        case POWER_SUPPLY_PROP_TECHNOLOGY:
                val->intval = acpi_battery_technology(battery);
                break;
        case POWER_SUPPLY_PROP_CYCLE_COUNT:
                val->intval = battery->cycle_count;
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
                if (battery->design_voltage == ACPI_BATTERY_VALUE_UNKNOWN)
                        ret = -ENODEV;
                else
                        val->intval = battery->design_voltage * 1000;
                break;
        case POWER_SUPPLY_PROP_VOLTAGE_NOW:
                if (battery->voltage_now == ACPI_BATTERY_VALUE_UNKNOWN)
                        ret = -ENODEV;
                else
                        val->intval = battery->voltage_now * 1000;
                break;
        case POWER_SUPPLY_PROP_CURRENT_NOW:
        case POWER_SUPPLY_PROP_POWER_NOW:
                if (battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN)
                        ret = -ENODEV;
                else
                        val->intval = battery->rate_now * 1000;
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
        case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
                if (!ACPI_BATTERY_CAPACITY_VALID(battery->design_capacity))
                        ret = -ENODEV;
                else
                        val->intval = battery->design_capacity * 1000;
                break;
        case POWER_SUPPLY_PROP_CHARGE_FULL:
        case POWER_SUPPLY_PROP_ENERGY_FULL:
                if (!ACPI_BATTERY_CAPACITY_VALID(battery->full_charge_capacity))
                        ret = -ENODEV;
                else
                        val->intval = battery->full_charge_capacity * 1000;
                break;
        case POWER_SUPPLY_PROP_CHARGE_NOW:
        case POWER_SUPPLY_PROP_ENERGY_NOW:
                if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN)
                        ret = -ENODEV;
                else
                        val->intval = battery->capacity_now * 1000;
                break;
        case POWER_SUPPLY_PROP_CAPACITY:
                if (ACPI_BATTERY_CAPACITY_VALID(battery->full_charge_capacity))
                        full_capacity = battery->full_charge_capacity;
                else if (ACPI_BATTERY_CAPACITY_VALID(battery->design_capacity))
                        full_capacity = battery->design_capacity;

                if (battery->capacity_now == ACPI_BATTERY_VALUE_UNKNOWN ||
                    full_capacity == ACPI_BATTERY_VALUE_UNKNOWN)
                        ret = -ENODEV;
                else
                        val->intval = DIV_ROUND_CLOSEST_ULL(battery->capacity_now * 100ULL,
                                        full_capacity);
                break;
        case POWER_SUPPLY_PROP_CAPACITY_LEVEL:
                if (battery->state & ACPI_BATTERY_STATE_CRITICAL)
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_CRITICAL;
                else if (test_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags) &&
                        (battery->capacity_now <= battery->alarm))
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_LOW;
                else if (acpi_battery_is_charged(battery))
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_FULL;
                else
                        val->intval = POWER_SUPPLY_CAPACITY_LEVEL_NORMAL;
                break;
        case POWER_SUPPLY_PROP_MODEL_NAME:
                val->strval = battery->model_number;
                break;
        case POWER_SUPPLY_PROP_MANUFACTURER:
                val->strval = battery->oem_info;
                break;
        case POWER_SUPPLY_PROP_SERIAL_NUMBER:
                val->strval = battery->serial_number;
                break;
        default:
                ret = -EINVAL;
        }
        return ret;
}

static const enum power_supply_property charge_battery_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_CYCLE_COUNT,
        POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
        POWER_SUPPLY_PROP_CHARGE_FULL,
        POWER_SUPPLY_PROP_CHARGE_NOW,
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_CAPACITY_LEVEL,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
        POWER_SUPPLY_PROP_SERIAL_NUMBER,
};

static const enum power_supply_property charge_battery_full_cap_broken_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_CYCLE_COUNT,
        POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_CURRENT_NOW,
        POWER_SUPPLY_PROP_CHARGE_NOW,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
        POWER_SUPPLY_PROP_SERIAL_NUMBER,
};

static const enum power_supply_property energy_battery_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_CYCLE_COUNT,
        POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_POWER_NOW,
        POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
        POWER_SUPPLY_PROP_ENERGY_FULL,
        POWER_SUPPLY_PROP_ENERGY_NOW,
        POWER_SUPPLY_PROP_CAPACITY,
        POWER_SUPPLY_PROP_CAPACITY_LEVEL,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
        POWER_SUPPLY_PROP_SERIAL_NUMBER,
};

static const enum power_supply_property energy_battery_full_cap_broken_props[] = {
        POWER_SUPPLY_PROP_STATUS,
        POWER_SUPPLY_PROP_PRESENT,
        POWER_SUPPLY_PROP_TECHNOLOGY,
        POWER_SUPPLY_PROP_CYCLE_COUNT,
        POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
        POWER_SUPPLY_PROP_VOLTAGE_NOW,
        POWER_SUPPLY_PROP_POWER_NOW,
        POWER_SUPPLY_PROP_ENERGY_NOW,
        POWER_SUPPLY_PROP_MODEL_NAME,
        POWER_SUPPLY_PROP_MANUFACTURER,
        POWER_SUPPLY_PROP_SERIAL_NUMBER,
};

/* Battery Management */
struct acpi_offsets {
        size_t offset;          /* offset inside struct acpi_sbs_battery */
        u8 mode;                /* int or string? */
};

static const struct acpi_offsets state_offsets[] = {
        {offsetof(struct acpi_battery, state), 0},
        {offsetof(struct acpi_battery, rate_now), 0},
        {offsetof(struct acpi_battery, capacity_now), 0},
        {offsetof(struct acpi_battery, voltage_now), 0},
};

static const struct acpi_offsets info_offsets[] = {
        {offsetof(struct acpi_battery, power_unit), 0},
        {offsetof(struct acpi_battery, design_capacity), 0},
        {offsetof(struct acpi_battery, full_charge_capacity), 0},
        {offsetof(struct acpi_battery, technology), 0},
        {offsetof(struct acpi_battery, design_voltage), 0},
        {offsetof(struct acpi_battery, design_capacity_warning), 0},
        {offsetof(struct acpi_battery, design_capacity_low), 0},
        {offsetof(struct acpi_battery, capacity_granularity_1), 0},
        {offsetof(struct acpi_battery, capacity_granularity_2), 0},
        {offsetof(struct acpi_battery, model_number), 1},
        {offsetof(struct acpi_battery, serial_number), 1},
        {offsetof(struct acpi_battery, type), 1},
        {offsetof(struct acpi_battery, oem_info), 1},
};

static const struct acpi_offsets extended_info_offsets[] = {
        {offsetof(struct acpi_battery, revision), 0},
        {offsetof(struct acpi_battery, power_unit), 0},
        {offsetof(struct acpi_battery, design_capacity), 0},
        {offsetof(struct acpi_battery, full_charge_capacity), 0},
        {offsetof(struct acpi_battery, technology), 0},
        {offsetof(struct acpi_battery, design_voltage), 0},
        {offsetof(struct acpi_battery, design_capacity_warning), 0},
        {offsetof(struct acpi_battery, design_capacity_low), 0},
        {offsetof(struct acpi_battery, cycle_count), 0},
        {offsetof(struct acpi_battery, measurement_accuracy), 0},
        {offsetof(struct acpi_battery, max_sampling_time), 0},
        {offsetof(struct acpi_battery, min_sampling_time), 0},
        {offsetof(struct acpi_battery, max_averaging_interval), 0},
        {offsetof(struct acpi_battery, min_averaging_interval), 0},
        {offsetof(struct acpi_battery, capacity_granularity_1), 0},
        {offsetof(struct acpi_battery, capacity_granularity_2), 0},
        {offsetof(struct acpi_battery, model_number), 1},
        {offsetof(struct acpi_battery, serial_number), 1},
        {offsetof(struct acpi_battery, type), 1},
        {offsetof(struct acpi_battery, oem_info), 1},
};

static int extract_package(struct acpi_battery *battery,
                           union acpi_object *package,
                           const struct acpi_offsets *offsets, int num)
{
        int i;
        union acpi_object *element;

        if (package->type != ACPI_TYPE_PACKAGE)
                return -EFAULT;
        for (i = 0; i < num; ++i) {
                if (package->package.count <= i)
                        return -EFAULT;
                element = &package->package.elements[i];
                if (offsets[i].mode) {
                        u8 *ptr = (u8 *)battery + offsets[i].offset;
                        u32 len = MAX_STRING_LENGTH;

                        switch (element->type) {
                        case ACPI_TYPE_BUFFER:
                                if (len > element->buffer.length + 1)
                                        len = element->buffer.length + 1;

                                fallthrough;
                        case ACPI_TYPE_STRING:
                                strscpy(ptr, element->string.pointer, len);

                                break;
                        case ACPI_TYPE_INTEGER:
                                strscpy(ptr, (u8 *)&element->integer.value, sizeof(u64) + 1);

                                break;
                        default:
                                *ptr = 0; /* don't have value */
                        }
                } else {
                        int *x = (int *)((u8 *)battery + offsets[i].offset);
                        *x = (element->type == ACPI_TYPE_INTEGER) ?
                                element->integer.value : -1;
                }
        }
        return 0;
}

static int acpi_battery_get_status(struct acpi_battery *battery)
{
        if (acpi_bus_get_status(battery->device)) {
                acpi_handle_info(battery->device->handle,
                                 "_STA evaluation failed\n");
                return -ENODEV;
        }
        return 0;
}


static int extract_battery_info(const int use_bix,
                         struct acpi_battery *battery,
                         const struct acpi_buffer *buffer)
{
        int result = -EFAULT;

        if (use_bix && battery_bix_broken_package)
                result = extract_package(battery, buffer->pointer,
                                extended_info_offsets + 1,
                                ARRAY_SIZE(extended_info_offsets) - 1);
        else if (use_bix)
                result = extract_package(battery, buffer->pointer,
                                extended_info_offsets,
                                ARRAY_SIZE(extended_info_offsets));
        else
                result = extract_package(battery, buffer->pointer,
                                info_offsets, ARRAY_SIZE(info_offsets));
        if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
                battery->full_charge_capacity = battery->design_capacity;
        if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH, &battery->flags) &&
            battery->power_unit && battery->design_voltage) {
                battery->design_capacity = battery->design_capacity *
                    10000 / battery->design_voltage;
                battery->full_charge_capacity = battery->full_charge_capacity *
                    10000 / battery->design_voltage;
                battery->design_capacity_warning =
                    battery->design_capacity_warning *
                    10000 / battery->design_voltage;
                /* Curiously, design_capacity_low, unlike the rest of them,
                 *  is correct.
                 */
                /* capacity_granularity_* equal 1 on the systems tested, so
                 * it's impossible to tell if they would need an adjustment
                 * or not if their values were higher.
                 */
        }
        if (test_bit(ACPI_BATTERY_QUIRK_DEGRADED_FULL_CHARGE, &battery->flags) &&
            battery->capacity_now > battery->full_charge_capacity)
                battery->capacity_now = battery->full_charge_capacity;

        return result;
}

static int acpi_battery_get_info(struct acpi_battery *battery)
{
        const int xinfo = test_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);
        int use_bix;
        int result = -ENODEV;

        if (!acpi_battery_present(battery))
                return 0;


        for (use_bix = xinfo ? 1 : 0; use_bix >= 0; use_bix--) {
                struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
                acpi_status status = AE_ERROR;

                status = acpi_evaluate_object(battery->device->handle,
                                              use_bix ? "_BIX":"_BIF",
                                              NULL, &buffer);

                if (ACPI_FAILURE(status)) {
                        acpi_handle_info(battery->device->handle,
                                         "%s evaluation failed: %s\n",
                                         use_bix ? "_BIX":"_BIF",
                                         acpi_format_exception(status));
                } else {
                        result = extract_battery_info(use_bix,
                                                      battery,
                                                      &buffer);

                        kfree(buffer.pointer);
                        break;
                }
        }

        if (!result && !use_bix && xinfo)
                pr_warn(FW_BUG "The _BIX method is broken, using _BIF.\n");

        return result;
}

static int acpi_battery_get_state(struct acpi_battery *battery)
{
        int result = 0;
        acpi_status status = 0;
        struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

        if (!acpi_battery_present(battery))
                return 0;

        if (battery->update_time &&
            time_before(jiffies, battery->update_time +
                        msecs_to_jiffies(cache_time)))
                return 0;

        status = acpi_evaluate_object(battery->device->handle, "_BST",
                                      NULL, &buffer);
        if (ACPI_FAILURE(status)) {
                acpi_handle_info(battery->device->handle,
                                 "_BST evaluation failed: %s",
                                 acpi_format_exception(status));
                return -ENODEV;
        }

        result = extract_package(battery, buffer.pointer,
                                 state_offsets, ARRAY_SIZE(state_offsets));
        battery->update_time = jiffies;
        kfree(buffer.pointer);

        /* For buggy DSDTs that report negative 16-bit values for either
         * charging or discharging current and/or report 0 as 65536
         * due to bad math.
         */
        if (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA &&
                battery->rate_now != ACPI_BATTERY_VALUE_UNKNOWN &&
                (s16)(battery->rate_now) < 0) {
                battery->rate_now = abs((s16)battery->rate_now);
                pr_warn_once(FW_BUG "(dis)charge rate invalid.\n");
        }

        if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags)
            && battery->capacity_now >= 0 && battery->capacity_now <= 100)
                battery->capacity_now = (battery->capacity_now *
                                battery->full_charge_capacity) / 100;
        if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH, &battery->flags) &&
            battery->power_unit && battery->design_voltage) {
                battery->capacity_now = battery->capacity_now *
                    10000 / battery->design_voltage;
        }
        if (test_bit(ACPI_BATTERY_QUIRK_DEGRADED_FULL_CHARGE, &battery->flags) &&
            battery->capacity_now > battery->full_charge_capacity)
                battery->capacity_now = battery->full_charge_capacity;

        return result;
}

static int acpi_battery_set_alarm(struct acpi_battery *battery)
{
        acpi_status status = 0;

        if (!acpi_battery_present(battery) ||
            !test_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags))
                return -ENODEV;

        status = acpi_execute_simple_method(battery->device->handle, "_BTP",
                                            battery->alarm);
        if (ACPI_FAILURE(status))
                return -ENODEV;

        acpi_handle_debug(battery->device->handle, "Alarm set to %d\n",
                          battery->alarm);

        return 0;
}

static int acpi_battery_init_alarm(struct acpi_battery *battery)
{
        /* See if alarms are supported, and if so, set default */
        if (!acpi_has_method(battery->device->handle, "_BTP")) {
                clear_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags);
                return 0;
        }
        set_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags);
        if (!battery->alarm)
                battery->alarm = battery->design_capacity_warning;
        return acpi_battery_set_alarm(battery);
}

static ssize_t acpi_battery_alarm_show(struct device *dev,
                                        struct device_attribute *attr,
                                        char *buf)
{
        struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));

        return sysfs_emit(buf, "%d\n", battery->alarm * 1000);
}

static ssize_t acpi_battery_alarm_store(struct device *dev,
                                        struct device_attribute *attr,
                                        const char *buf, size_t count)
{
        unsigned long x;
        struct acpi_battery *battery = to_acpi_battery(dev_get_drvdata(dev));

        if (sscanf(buf, "%lu\n", &x) == 1)
                battery->alarm = x/1000;
        if (acpi_battery_present(battery))
                acpi_battery_set_alarm(battery);
        return count;
}

static struct device_attribute alarm_attr = {
        .attr = {.name = "alarm", .mode = 0644},
        .show = acpi_battery_alarm_show,
        .store = acpi_battery_alarm_store,
};

static struct attribute *acpi_battery_attrs[] = {
        &alarm_attr.attr,
        NULL
};
ATTRIBUTE_GROUPS(acpi_battery);

/*
 * The Battery Hooking API
 *
 * This API is used inside other drivers that need to expose
 * platform-specific behaviour within the generic driver in a
 * generic way.
 *
 */

static LIST_HEAD(acpi_battery_list);
static LIST_HEAD(battery_hook_list);
static DEFINE_MUTEX(hook_mutex);

static void battery_hook_unregister_unlocked(struct acpi_battery_hook *hook)
{
        struct acpi_battery *battery;

        /*
         * In order to remove a hook, we first need to
         * de-register all the batteries that are registered.
         */
        list_for_each_entry(battery, &acpi_battery_list, list) {
                if (!hook->remove_battery(battery->bat, hook))
                        power_supply_changed(battery->bat);
        }
        list_del_init(&hook->list);

        pr_info("hook unregistered: %s\n", hook->name);
}

void battery_hook_unregister(struct acpi_battery_hook *hook)
{
        mutex_lock(&hook_mutex);
        /*
         * Ignore already unregistered battery hooks. This might happen
         * if a battery hook was previously unloaded due to an error when
         * adding a new battery.
         */
        if (!list_empty(&hook->list))
                battery_hook_unregister_unlocked(hook);

        mutex_unlock(&hook_mutex);
}
EXPORT_SYMBOL_GPL(battery_hook_unregister);

void battery_hook_register(struct acpi_battery_hook *hook)
{
        struct acpi_battery *battery;

        mutex_lock(&hook_mutex);
        list_add(&hook->list, &battery_hook_list);
        /*
         * Now that the driver is registered, we need
         * to notify the hook that a battery is available
         * for each battery, so that the driver may add
         * its attributes.
         */
        list_for_each_entry(battery, &acpi_battery_list, list) {
                if (hook->add_battery(battery->bat, hook)) {
                        /*
                         * If a add-battery returns non-zero,
                         * the registration of the hook has failed,
                         * and we will not add it to the list of loaded
                         * hooks.
                         */
                        pr_err("hook failed to load: %s", hook->name);
                        battery_hook_unregister_unlocked(hook);
                        goto end;
                }

                power_supply_changed(battery->bat);
        }
        pr_info("new hook: %s\n", hook->name);
end:
        mutex_unlock(&hook_mutex);
}
EXPORT_SYMBOL_GPL(battery_hook_register);

static void devm_battery_hook_unregister(void *data)
{
        struct acpi_battery_hook *hook = data;

        battery_hook_unregister(hook);
}

int devm_battery_hook_register(struct device *dev, struct acpi_battery_hook *hook)
{
        battery_hook_register(hook);

        return devm_add_action_or_reset(dev, devm_battery_hook_unregister, hook);
}
EXPORT_SYMBOL_GPL(devm_battery_hook_register);

/*
 * This function gets called right after the battery sysfs
 * attributes have been added, so that the drivers that
 * define custom sysfs attributes can add their own.
 */
static void battery_hook_add_battery(struct acpi_battery *battery)
{
        struct acpi_battery_hook *hook_node, *tmp;

        mutex_lock(&hook_mutex);
        INIT_LIST_HEAD(&battery->list);
        list_add(&battery->list, &acpi_battery_list);
        /*
         * Since we added a new battery to the list, we need to
         * iterate over the hooks and call add_battery for each
         * hook that was registered. This usually happens
         * when a battery gets hotplugged or initialized
         * during the battery module initialization.
         */
        list_for_each_entry_safe(hook_node, tmp, &battery_hook_list, list) {
                if (hook_node->add_battery(battery->bat, hook_node)) {
                        /*
                         * The notification of the hook has failed, to
                         * prevent further errors we will unload the hook.
                         */
                        pr_err("error in hook, unloading: %s",
                                        hook_node->name);
                        battery_hook_unregister_unlocked(hook_node);
                }
        }
        mutex_unlock(&hook_mutex);
}

static void battery_hook_remove_battery(struct acpi_battery *battery)
{
        struct acpi_battery_hook *hook;

        mutex_lock(&hook_mutex);
        /*
         * Before removing the hook, we need to remove all
         * custom attributes from the battery.
         */
        list_for_each_entry(hook, &battery_hook_list, list) {
                hook->remove_battery(battery->bat, hook);
        }
        /* Then, just remove the battery from the list */
        list_del(&battery->list);
        mutex_unlock(&hook_mutex);
}

static void __exit battery_hook_exit(void)
{
        struct acpi_battery_hook *hook;
        struct acpi_battery_hook *ptr;
        /*
         * At this point, the acpi_bus_unregister_driver()
         * has called remove for all batteries. We just
         * need to remove the hooks.
         */
        list_for_each_entry_safe(hook, ptr, &battery_hook_list, list) {
                battery_hook_unregister(hook);
        }
        mutex_destroy(&hook_mutex);
}

static int sysfs_add_battery(struct acpi_battery *battery)
{
        struct power_supply_config psy_cfg = {
                .drv_data = battery,
                .attr_grp = acpi_battery_groups,
                .no_wakeup_source = true,
        };
        bool full_cap_broken = false;

        if (!ACPI_BATTERY_CAPACITY_VALID(battery->full_charge_capacity) &&
            !ACPI_BATTERY_CAPACITY_VALID(battery->design_capacity))
                full_cap_broken = true;

        if (battery->power_unit == ACPI_BATTERY_POWER_UNIT_MA) {
                if (full_cap_broken) {
                        battery->bat_desc.properties =
                            charge_battery_full_cap_broken_props;
                        battery->bat_desc.num_properties =
                            ARRAY_SIZE(charge_battery_full_cap_broken_props);
                } else {
                        battery->bat_desc.properties = charge_battery_props;
                        battery->bat_desc.num_properties =
                            ARRAY_SIZE(charge_battery_props);
                }
        } else {
                if (full_cap_broken) {
                        battery->bat_desc.properties =
                            energy_battery_full_cap_broken_props;
                        battery->bat_desc.num_properties =
                            ARRAY_SIZE(energy_battery_full_cap_broken_props);
                } else {
                        battery->bat_desc.properties = energy_battery_props;
                        battery->bat_desc.num_properties =
                            ARRAY_SIZE(energy_battery_props);
                }
        }

        battery->bat_desc.name = acpi_device_bid(battery->device);
        battery->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
        battery->bat_desc.get_property = acpi_battery_get_property;

        battery->bat = power_supply_register(&battery->device->dev,
                                &battery->bat_desc, &psy_cfg);

        if (IS_ERR(battery->bat)) {
                int result = PTR_ERR(battery->bat);

                battery->bat = NULL;
                return result;
        }
        battery_hook_add_battery(battery);
        return 0;
}

static void sysfs_remove_battery(struct acpi_battery *battery)
{
        if (!battery->bat)
                return;

        battery_hook_remove_battery(battery);
        power_supply_unregister(battery->bat);
        battery->bat = NULL;
}

static void find_battery(const struct dmi_header *dm, void *private)
{
        struct acpi_battery *battery = (struct acpi_battery *)private;
        /* Note: the hardcoded offsets below have been extracted from
         * the source code of dmidecode.
         */
        if (dm->type == DMI_ENTRY_PORTABLE_BATTERY && dm->length >= 8) {
                const u8 *dmi_data = (const u8 *)(dm + 1);
                int dmi_capacity = get_unaligned((const u16 *)(dmi_data + 6));

                if (dm->length >= 18)
                        dmi_capacity *= dmi_data[17];
                if (battery->design_capacity * battery->design_voltage / 1000
                    != dmi_capacity &&
                    battery->design_capacity * 10 == dmi_capacity)
                        set_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH,
                                &battery->flags);
        }
}

/*
 * According to the ACPI spec, some kinds of primary batteries can
 * report percentage battery remaining capacity directly to OS.
 * In this case, it reports the Last Full Charged Capacity == 100
 * and BatteryPresentRate == 0xFFFFFFFF.
 *
 * Now we found some battery reports percentage remaining capacity
 * even if it's rechargeable.
 * https://bugzilla.kernel.org/show_bug.cgi?id=15979
 *
 * Handle this correctly so that they won't break userspace.
 */
static void acpi_battery_quirks(struct acpi_battery *battery)
{
        if (test_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags))
                return;

        if (battery->full_charge_capacity == 100 &&
                battery->rate_now == ACPI_BATTERY_VALUE_UNKNOWN &&
                battery->capacity_now >= 0 && battery->capacity_now <= 100) {
                set_bit(ACPI_BATTERY_QUIRK_PERCENTAGE_CAPACITY, &battery->flags);
                battery->full_charge_capacity = battery->design_capacity;
                battery->capacity_now = (battery->capacity_now *
                                battery->full_charge_capacity) / 100;
        }

        if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH, &battery->flags))
                return;

        if (battery->power_unit && dmi_name_in_vendors("LENOVO")) {
                const char *s;

                s = dmi_get_system_info(DMI_PRODUCT_VERSION);
                if (s && !strncasecmp(s, "ThinkPad", 8)) {
                        dmi_walk(find_battery, battery);
                        if (test_bit(ACPI_BATTERY_QUIRK_THINKPAD_MAH,
                                     &battery->flags) &&
                            battery->design_voltage) {
                                battery->design_capacity =
                                    battery->design_capacity *
                                    10000 / battery->design_voltage;
                                battery->full_charge_capacity =
                                    battery->full_charge_capacity *
                                    10000 / battery->design_voltage;
                                battery->design_capacity_warning =
                                    battery->design_capacity_warning *
                                    10000 / battery->design_voltage;
                                battery->capacity_now = battery->capacity_now *
                                    10000 / battery->design_voltage;
                        }
                }
        }

        if (test_bit(ACPI_BATTERY_QUIRK_DEGRADED_FULL_CHARGE, &battery->flags))
                return;

        if (acpi_battery_is_degraded(battery) &&
            battery->capacity_now > battery->full_charge_capacity) {
                set_bit(ACPI_BATTERY_QUIRK_DEGRADED_FULL_CHARGE, &battery->flags);
                battery->capacity_now = battery->full_charge_capacity;
        }
}

static int acpi_battery_update(struct acpi_battery *battery, bool resume)
{
        int result = acpi_battery_get_status(battery);

        if (result)
                return result;

        if (!acpi_battery_present(battery)) {
                sysfs_remove_battery(battery);
                battery->update_time = 0;
                return 0;
        }

        if (resume)
                return 0;

        if (!battery->update_time) {
                result = acpi_battery_get_info(battery);
                if (result)
                        return result;
                acpi_battery_init_alarm(battery);
        }

        result = acpi_battery_get_state(battery);
        if (result)
                return result;
        acpi_battery_quirks(battery);

        if (!battery->bat) {
                result = sysfs_add_battery(battery);
                if (result)
                        return result;
        }

        /*
         * Wakeup the system if battery is critical low
         * or lower than the alarm level
         */
        if ((battery->state & ACPI_BATTERY_STATE_CRITICAL) ||
            (test_bit(ACPI_BATTERY_ALARM_PRESENT, &battery->flags) &&
             (battery->capacity_now <= battery->alarm)))
                acpi_pm_wakeup_event(&battery->device->dev);

        return result;
}

static void acpi_battery_refresh(struct acpi_battery *battery)
{
        int power_unit;

        if (!battery->bat)
                return;

        power_unit = battery->power_unit;

        acpi_battery_get_info(battery);

        if (power_unit == battery->power_unit)
                return;

        /* The battery has changed its reporting units. */
        sysfs_remove_battery(battery);
        sysfs_add_battery(battery);
}

/* Driver Interface */
static void acpi_battery_notify(acpi_handle handle, u32 event, void *data)
{
        struct acpi_battery *battery = data;
        struct acpi_device *device = battery->device;
        struct power_supply *old;

        guard(mutex)(&battery->update_lock);

        old = battery->bat;
        /*
         * On Acer Aspire V5-573G notifications are sometimes triggered too
         * early. For example, when AC is unplugged and notification is
         * triggered, battery state is still reported as "Full", and changes to
         * "Discharging" only after short delay, without any notification.
         */
        if (battery_notification_delay_ms > 0)
                msleep(battery_notification_delay_ms);
        if (event == ACPI_BATTERY_NOTIFY_INFO)
                acpi_battery_refresh(battery);
        acpi_battery_update(battery, false);
        acpi_bus_generate_netlink_event(device->pnp.device_class,
                                        dev_name(&device->dev), event,
                                        acpi_battery_present(battery));
        acpi_notifier_call_chain(device, event, acpi_battery_present(battery));
        /* acpi_battery_update could remove power_supply object */
        if (old && battery->bat)
                power_supply_changed(battery->bat);
}

static int battery_notify(struct notifier_block *nb,
                          unsigned long mode, void *_unused)
{
        struct acpi_battery *battery = container_of(nb, struct acpi_battery,
                                                    pm_nb);

        if (mode == PM_POST_SUSPEND || mode == PM_POST_HIBERNATION) {
                guard(mutex)(&battery->update_lock);

                if (!acpi_battery_present(battery))
                        return 0;

                if (battery->bat) {
                        acpi_battery_refresh(battery);
                } else {
                        int result;

                        result = acpi_battery_get_info(battery);
                        if (result)
                                return result;

                        result = sysfs_add_battery(battery);
                        if (result)
                                return result;
                }

                acpi_battery_init_alarm(battery);
                acpi_battery_get_state(battery);
        }

        return 0;
}

static int __init
battery_bix_broken_package_quirk(const struct dmi_system_id *d)
{
        battery_bix_broken_package = 1;
        return 0;
}

static int __init
battery_notification_delay_quirk(const struct dmi_system_id *d)
{
        battery_notification_delay_ms = 1000;
        return 0;
}

static int __init
battery_ac_is_broken_quirk(const struct dmi_system_id *d)
{
        battery_ac_is_broken = 1;
        return 0;
}

static const struct dmi_system_id bat_dmi_table[] __initconst = {
        {
                /* NEC LZ750/LS */
                .callback = battery_bix_broken_package_quirk,
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "NEC"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "PC-LZ750LS"),
                },
        },
        {
                /* Acer Aspire V5-573G */
                .callback = battery_notification_delay_quirk,
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Aspire V5-573G"),
                },
        },
        {
                /* Point of View mobii wintab p800w */
                .callback = battery_ac_is_broken_quirk,
                .matches = {
                        DMI_MATCH(DMI_BOARD_VENDOR, "AMI Corporation"),
                        DMI_MATCH(DMI_BOARD_NAME, "Aptio CRB"),
                        DMI_MATCH(DMI_BIOS_VERSION, "3BAIR1013"),
                        /* Above matches are too generic, add bios-date match */
                        DMI_MATCH(DMI_BIOS_DATE, "08/22/2014"),
                },
        },
        {
                /* Microsoft Surface Go 3 */
                .callback = battery_notification_delay_quirk,
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "Surface Go 3"),
                },
        },
        {},
};

/*
 * Some machines'(E,G Lenovo Z480) ECs are not stable
 * during boot up and this causes battery driver fails to be
 * probed due to failure of getting battery information
 * from EC sometimes. After several retries, the operation
 * may work. So add retry code here and 20ms sleep between
 * every retries.
 */
static int acpi_battery_update_retry(struct acpi_battery *battery)
{
        int retry, ret;

        guard(mutex)(&battery->update_lock);

        for (retry = 5; retry; retry--) {
                ret = acpi_battery_update(battery, false);
                if (!ret)
                        break;

                msleep(20);
        }
        return ret;
}

static void sysfs_battery_cleanup(struct acpi_battery *battery)
{
        guard(mutex)(&battery->update_lock);

        sysfs_remove_battery(battery);
}

static int acpi_battery_probe(struct platform_device *pdev)
{
        struct acpi_device *device = ACPI_COMPANION(&pdev->dev);
        struct acpi_battery *battery;
        int result;

        if (device->dep_unmet)
                return -EPROBE_DEFER;

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

        platform_set_drvdata(pdev, battery);

        battery->device = device;
        strscpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
        strscpy(acpi_device_class(device), ACPI_BATTERY_CLASS);

        result = devm_mutex_init(&pdev->dev, &battery->update_lock);
        if (result)
                return result;

        if (acpi_has_method(battery->device->handle, "_BIX"))
                set_bit(ACPI_BATTERY_XINFO_PRESENT, &battery->flags);

        result = acpi_battery_update_retry(battery);
        if (result)
                goto fail;

        pr_info("Slot [%s] (battery %s)\n", acpi_device_bid(device),
                device->status.battery_present ? "present" : "absent");

        battery->pm_nb.notifier_call = battery_notify;
        result = register_pm_notifier(&battery->pm_nb);
        if (result)
                goto fail;

        device_init_wakeup(&pdev->dev, true);

        result = acpi_dev_install_notify_handler(device, ACPI_ALL_NOTIFY,
                                                 acpi_battery_notify, battery);
        if (result)
                goto fail_pm;

        return 0;

fail_pm:
        device_init_wakeup(&pdev->dev, false);
        unregister_pm_notifier(&battery->pm_nb);
fail:
        sysfs_battery_cleanup(battery);

        return result;
}

static void acpi_battery_remove(struct platform_device *pdev)
{
        struct acpi_battery *battery = platform_get_drvdata(pdev);

        acpi_dev_remove_notify_handler(battery->device, ACPI_ALL_NOTIFY,
                                       acpi_battery_notify);

        device_init_wakeup(&pdev->dev, false);
        unregister_pm_notifier(&battery->pm_nb);

        sysfs_battery_cleanup(battery);
}

/* this is needed to learn about changes made in suspended state */
static int acpi_battery_resume(struct device *dev)
{
        struct acpi_battery *battery = dev_get_drvdata(dev);

        if (!battery)
                return -EINVAL;

        battery->update_time = 0;

        guard(mutex)(&battery->update_lock);

        acpi_battery_update(battery, true);
        return 0;
}

static DEFINE_SIMPLE_DEV_PM_OPS(acpi_battery_pm, NULL, acpi_battery_resume);

static struct platform_driver acpi_battery_driver = {
        .probe = acpi_battery_probe,
        .remove = acpi_battery_remove,
        .driver = {
                .name = "acpi-battery",
                .acpi_match_table = battery_device_ids,
                .pm = pm_sleep_ptr(&acpi_battery_pm),
                .probe_type = PROBE_PREFER_ASYNCHRONOUS,
        },
};

static int __init acpi_battery_init(void)
{
        if (acpi_disabled || acpi_quirk_skip_acpi_ac_and_battery())
                return -ENODEV;

        dmi_check_system(bat_dmi_table);

        return platform_driver_register(&acpi_battery_driver);
}

static void __exit acpi_battery_exit(void)
{
        platform_driver_unregister(&acpi_battery_driver);
        battery_hook_exit();
}

module_init(acpi_battery_init);
module_exit(acpi_battery_exit);