Adding upstream version 6.1.76.upstream/6.1.76

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1295 insertions, 0 deletions

diff --git a/drivers/acpi/battery.c b/drivers/acpi/battery.c
new file mode 100644
index 000000000..084f156bd
--- /dev/null
+++ b/drivers/acpi/battery.c
@@ -0,0 +1,1295 @@
+// 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)
+				strscpy(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) {
+		hook->remove_battery(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)) {
+			/*
+			 * 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;
+		}
+	}
+	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)) {
+			/*
+			 * 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);
+	}
+	/* 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 int acpi_battery_remove(struct acpi_device *device)
+{
+	struct acpi_battery *battery = NULL;
+
+	if (!device || !acpi_driver_data(device))
+		return -EINVAL;
+	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);
+	return 0;
+}
+
+#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);