Contributors: 61
Author Tokens Token Proportion Commits Commit Proportion
Alexey Y. Starikovskiy 1731 31.36% 16 12.31%
Andy Grover 507 9.19% 5 3.85%
Ognjen Galic 415 7.52% 1 0.77%
Kamil Iskra 336 6.09% 1 0.77%
Rui Zhang 286 5.18% 4 3.08%
Lan Tianyu 285 5.16% 13 10.00%
Vladimir Lebedev 268 4.86% 2 1.54%
Hans de Goede 252 4.57% 10 7.69%
Dave Lambley 193 3.50% 1 0.77%
Rafael J. Wysocki 166 3.01% 7 5.38%
Andrey Borzenkov 163 2.95% 2 1.54%
Laszlo Toth 133 2.41% 1 0.77%
Kyle McMartin 86 1.56% 1 0.77%
Thomas Renninger 86 1.56% 2 1.54%
Alexander Mezin 82 1.49% 4 3.08%
Richard Hughes 72 1.30% 1 0.77%
Krzysztof Kozlowski 58 1.05% 2 1.54%
Jiri Kosina 43 0.78% 1 0.77%
Patrick Mochel 33 0.60% 2 1.54%
Hector Martin 32 0.58% 1 0.77%
Luis Henriques 25 0.45% 3 2.31%
Dmitry Rozhkov 21 0.38% 3 2.31%
Andy Whitcroft 19 0.34% 1 0.77%
Arjan van de Ven 19 0.34% 1 0.77%
Jouke Witteveen 18 0.33% 1 0.77%
Srinivas Pandruvada 18 0.33% 1 0.77%
Carlos Garnacho 16 0.29% 1 0.77%
Stefan Hajnoczi 16 0.29% 2 1.54%
Sergey Senozhatsky 16 0.29% 1 0.77%
Maximilian Luz 14 0.25% 1 0.77%
Maximilian Attems 13 0.24% 1 0.77%
Armin Wolf 11 0.20% 2 1.54%
Björn Helgaas 10 0.18% 1 0.77%
Jiang Liu 9 0.16% 2 1.54%
Mathias Krause 8 0.14% 2 1.54%
Xiaofei Tan 8 0.14% 1 0.77%
Shuah Khan 6 0.11% 1 0.77%
Roland Dreier 6 0.11% 1 0.77%
Len Brown 4 0.07% 4 3.08%
Christoph Hellwig 3 0.05% 1 0.77%
Carlo Caione 3 0.05% 1 0.77%
Dawei Li 2 0.04% 1 0.77%
Lin Ming 2 0.04% 1 0.77%
Thomas Gleixner 2 0.04% 1 0.77%
Linus Torvalds 2 0.04% 2 1.54%
Nicholas Mazzuca 2 0.04% 1 0.77%
Pavel Machek 2 0.04% 1 0.77%
Andrew Morton 2 0.04% 1 0.77%
Chris Wilson 2 0.04% 1 0.77%
Tejun Heo 2 0.04% 1 0.77%
Rasmus Villemoes 1 0.02% 1 0.77%
Lv Zheng 1 0.02% 1 0.77%
Andy Shevchenko 1 0.02% 1 0.77%
Werner Sembach 1 0.02% 1 0.77%
Burman Yan 1 0.02% 1 0.77%
Justin P. Mattock 1 0.02% 1 0.77%
André Almeida 1 0.02% 1 0.77%
Luis Gonzalez Fernandez 1 0.02% 1 0.77%
Lucas Magasweran 1 0.02% 1 0.77%
Colin Ian King 1 0.02% 1 0.77%
Bhumika Goyal 1 0.02% 1 0.77%
Total 5519 130 


// 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/async.h>
#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/slab.h>
#include <linux/suspend.h>
#include <linux/types.h>

#include <asm/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

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

static async_cookie_t async_cookie;
static bool battery_driver_registered;
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 lock;
	struct mutex sysfs_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[32];
	char serial_number[32];
	char type[32];
	char oem_info[32];
	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 or critical low */
	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)
			val->intval = POWER_SUPPLY_STATUS_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 = battery->capacity_now * 100/
					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 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 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 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 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;

			if (element->type == ACPI_TYPE_STRING ||
			    element->type == ACPI_TYPE_BUFFER)
				strncpy(ptr, element->string.pointer, 32);
			else if (element->type == ACPI_TYPE_INTEGER) {
				strncpy(ptr, (u8 *)&element->integer.value,
					sizeof(u64));
				ptr[sizeof(u64)] = 0;
			} else
				*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;

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

		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;

	mutex_lock(&battery->lock);
	status = acpi_evaluate_object(battery->device->handle, "_BST",
				      NULL, &buffer);
	mutex_unlock(&battery->lock);

	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;

	mutex_lock(&battery->lock);
	status = acpi_execute_simple_method(battery->device->handle, "_BTP",
					    battery->alarm);
	mutex_unlock(&battery->lock);

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

/*
 * 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(struct acpi_battery_hook *hook, int lock)
{
	struct acpi_battery *battery;
	/*
	 * In order to remove a hook, we first need to
	 * de-register all the batteries that are registered.
	 */
	if (lock)
		mutex_lock(&hook_mutex);
	list_for_each_entry(battery, &acpi_battery_list, list) {
		if (!hook->remove_battery(battery->bat, hook))
			power_supply_changed(battery->bat);
	}
	list_del(&hook->list);
	if (lock)
		mutex_unlock(&hook_mutex);
	pr_info("extension unregistered: %s\n", hook->name);
}

void battery_hook_unregister(struct acpi_battery_hook *hook)
{
	__battery_hook_unregister(hook, 1);
}
EXPORT_SYMBOL_GPL(battery_hook_unregister);

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

	mutex_lock(&hook_mutex);
	INIT_LIST_HEAD(&hook->list);
	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 extension has failed,
			 * and we will not add it to the list of loaded
			 * hooks.
			 */
			pr_err("extension failed to load: %s", hook->name);
			__battery_hook_unregister(hook, 0);
			goto end;
		}

		power_supply_changed(battery->bat);
	}
	pr_info("new extension: %s\n", hook->name);
end:
	mutex_unlock(&hook_mutex);
}
EXPORT_SYMBOL_GPL(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 extensions has failed, to
			 * prevent further errors we will unload the extension.
			 */
			pr_err("error in extension, unloading: %s",
					hook_node->name);
			__battery_hook_unregister(hook_node, 0);
		}
	}
	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, 1);
	}
	mutex_destroy(&hook_mutex);
}

static int sysfs_add_battery(struct acpi_battery *battery)
{
	struct power_supply_config psy_cfg = { .drv_data = battery, };
	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_no_ws(&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 device_create_file(&battery->bat->dev, &alarm_attr);
}

static void sysfs_remove_battery(struct acpi_battery *battery)
{
	mutex_lock(&battery->sysfs_lock);
	if (!battery->bat) {
		mutex_unlock(&battery->sysfs_lock);
		return;
	}
	battery_hook_remove_battery(battery);
	device_remove_file(&battery->bat->dev, &alarm_attr);
	power_supply_unregister(battery->bat);
	battery->bat = NULL;
	mutex_unlock(&battery->sysfs_lock);
}

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(struct acpi_device *device, u32 event)
{
	struct acpi_battery *battery = acpi_driver_data(device);
	struct power_supply *old;

	if (!battery)
		return;
	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);
	int result;

	switch (mode) {
	case PM_POST_HIBERNATION:
	case PM_POST_SUSPEND:
		if (!acpi_battery_present(battery))
			return 0;

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

	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;

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

		msleep(20);
	}
	return ret;
}

static int acpi_battery_add(struct acpi_device *device)
{
	int result = 0;
	struct acpi_battery *battery = NULL;

	if (!device)
		return -EINVAL;

	if (device->dep_unmet)
		return -EPROBE_DEFER;

	battery = kzalloc(sizeof(struct acpi_battery), GFP_KERNEL);
	if (!battery)
		return -ENOMEM;
	battery->device = device;
	strcpy(acpi_device_name(device), ACPI_BATTERY_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_BATTERY_CLASS);
	device->driver_data = battery;
	mutex_init(&battery->lock);
	mutex_init(&battery->sysfs_lock);
	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;
	register_pm_notifier(&battery->pm_nb);

	device_init_wakeup(&device->dev, 1);

	return result;

fail:
	sysfs_remove_battery(battery);
	mutex_destroy(&battery->lock);
	mutex_destroy(&battery->sysfs_lock);
	kfree(battery);
	return result;
}

static void acpi_battery_remove(struct acpi_device *device)
{
	struct acpi_battery *battery = NULL;

	if (!device || !acpi_driver_data(device))
		return;
	device_init_wakeup(&device->dev, 0);
	battery = acpi_driver_data(device);
	unregister_pm_notifier(&battery->pm_nb);
	sysfs_remove_battery(battery);
	mutex_destroy(&battery->lock);
	mutex_destroy(&battery->sysfs_lock);
	kfree(battery);
}

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

	if (!dev)
		return -EINVAL;

	battery = acpi_driver_data(to_acpi_device(dev));
	if (!battery)
		return -EINVAL;

	battery->update_time = 0;
	acpi_battery_update(battery, true);
	return 0;
}
#else
#define acpi_battery_resume NULL
#endif

static SIMPLE_DEV_PM_OPS(acpi_battery_pm, NULL, acpi_battery_resume);

static struct acpi_driver acpi_battery_driver = {
	.name = "battery",
	.class = ACPI_BATTERY_CLASS,
	.ids = battery_device_ids,
	.flags = ACPI_DRIVER_ALL_NOTIFY_EVENTS,
	.ops = {
		.add = acpi_battery_add,
		.remove = acpi_battery_remove,
		.notify = acpi_battery_notify,
		},
	.drv.pm = &acpi_battery_pm,
};

static void __init acpi_battery_init_async(void *unused, async_cookie_t cookie)
{
	int result;

	if (acpi_quirk_skip_acpi_ac_and_battery())
		return;

	dmi_check_system(bat_dmi_table);

	result = acpi_bus_register_driver(&acpi_battery_driver);
	battery_driver_registered = (result == 0);
}

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

	async_cookie = async_schedule(acpi_battery_init_async, NULL);
	return 0;
}

static void __exit acpi_battery_exit(void)
{
	async_synchronize_cookie(async_cookie + 1);
	if (battery_driver_registered) {
		acpi_bus_unregister_driver(&acpi_battery_driver);
		battery_hook_exit();
	}
}

module_init(acpi_battery_init);
module_exit(acpi_battery_exit);