sbs.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 *  sbs.c - ACPI Smart Battery System Driver ($Revision: 2.0 $)
 *
 *  Copyright (c) 2007 Alexey Starikovskiy <astarikovskiy@suse.de>
 *  Copyright (c) 2005-2007 Vladimir Lebedev <vladimir.p.lebedev@intel.com>
 *  Copyright (c) 2005 Rich Townsend <rhdt@bartol.udel.edu>
 */

#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/kernel.h>

#include <linux/acpi.h>
#include <linux/timer.h>
#include <linux/jiffies.h>
#include <linux/delay.h>
#include <linux/power_supply.h>
#include <linux/platform_data/x86/apple.h>
#include <acpi/battery.h>

#include "sbshc.h"

#define PREFIX "ACPI: "

#define ACPI_SBS_CLASS			"sbs"
#define ACPI_AC_CLASS			"ac_adapter"
#define ACPI_SBS_DEVICE_NAME		"Smart Battery System"
#define ACPI_BATTERY_DIR_NAME		"BAT%i"
#define ACPI_AC_DIR_NAME		"AC0"

#define ACPI_SBS_NOTIFY_STATUS		0x80
#define ACPI_SBS_NOTIFY_INFO		0x81

MODULE_AUTHOR("Alexey Starikovskiy <astarikovskiy@suse.de>");
MODULE_DESCRIPTION("Smart Battery System ACPI interface driver");
MODULE_LICENSE("GPL");

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

#define MAX_SBS_BAT			4
#define ACPI_SBS_BLOCK_MAX		32

static const struct acpi_device_id sbs_device_ids[] = {
	{"ACPI0002", 0},
	{"", 0},
};
MODULE_DEVICE_TABLE(acpi, sbs_device_ids);

struct acpi_battery {
	struct power_supply *bat;
	struct power_supply_desc bat_desc;
	struct acpi_sbs *sbs;
	unsigned long update_time;
	char name[8];
	char manufacturer_name[ACPI_SBS_BLOCK_MAX];
	char device_name[ACPI_SBS_BLOCK_MAX];
	char device_chemistry[ACPI_SBS_BLOCK_MAX];
	u16 alarm_capacity;
	u16 full_charge_capacity;
	u16 design_capacity;
	u16 design_voltage;
	u16 serial_number;
	u16 cycle_count;
	u16 temp_now;
	u16 voltage_now;
	s16 rate_now;
	s16 rate_avg;
	u16 capacity_now;
	u16 state_of_charge;
	u16 state;
	u16 mode;
	u16 spec;
	u8 id;
	u8 present:1;
	u8 have_sysfs_alarm:1;
};

#define to_acpi_battery(x) power_supply_get_drvdata(x)

struct acpi_sbs {
	struct power_supply *charger;
	struct acpi_device *device;
	struct acpi_smb_hc *hc;
	struct mutex lock;
	struct acpi_battery battery[MAX_SBS_BAT];
	u8 batteries_supported:4;
	u8 manager_present:1;
	u8 charger_present:1;
	u8 charger_exists:1;
};

#define to_acpi_sbs(x) power_supply_get_drvdata(x)

static int acpi_sbs_remove(struct acpi_device *device);
static int acpi_battery_get_state(struct acpi_battery *battery);

static inline int battery_scale(int log)
{
	int scale = 1;
	while (log--)
		scale *= 10;
	return scale;
}

static inline int acpi_battery_vscale(struct acpi_battery *battery)
{
	return battery_scale((battery->spec & 0x0f00) >> 8);
}

static inline int acpi_battery_ipscale(struct acpi_battery *battery)
{
	return battery_scale((battery->spec & 0xf000) >> 12);
}

static inline int acpi_battery_mode(struct acpi_battery *battery)
{
	return (battery->mode & 0x8000);
}

static inline int acpi_battery_scale(struct acpi_battery *battery)
{
	return (acpi_battery_mode(battery) ? 10 : 1) *
	    acpi_battery_ipscale(battery);
}

static int sbs_get_ac_property(struct power_supply *psy,
			       enum power_supply_property psp,
			       union power_supply_propval *val)
{
	struct acpi_sbs *sbs = to_acpi_sbs(psy);
	switch (psp) {
	case POWER_SUPPLY_PROP_ONLINE:
		val->intval = sbs->charger_present;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

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

static int acpi_sbs_battery_get_property(struct power_supply *psy,
					 enum power_supply_property psp,
					 union power_supply_propval *val)
{
	struct acpi_battery *battery = to_acpi_battery(psy);

	if ((!battery->present) && psp != POWER_SUPPLY_PROP_PRESENT)
		return -ENODEV;

	acpi_battery_get_state(battery);
	switch (psp) {
	case POWER_SUPPLY_PROP_STATUS:
		if (battery->rate_now < 0)
			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
		else if (battery->rate_now > 0)
			val->intval = POWER_SUPPLY_STATUS_CHARGING;
		else
			val->intval = POWER_SUPPLY_STATUS_FULL;
		break;
	case POWER_SUPPLY_PROP_PRESENT:
		val->intval = battery->present;
		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:
		val->intval = battery->design_voltage *
			acpi_battery_vscale(battery) * 1000;
		break;
	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
		val->intval = battery->voltage_now *
				acpi_battery_vscale(battery) * 1000;
		break;
	case POWER_SUPPLY_PROP_CURRENT_NOW:
	case POWER_SUPPLY_PROP_POWER_NOW:
		val->intval = abs(battery->rate_now) *
				acpi_battery_ipscale(battery) * 1000;
		val->intval *= (acpi_battery_mode(battery)) ?
				(battery->voltage_now *
				acpi_battery_vscale(battery) / 1000) : 1;
		break;
	case POWER_SUPPLY_PROP_CURRENT_AVG:
	case POWER_SUPPLY_PROP_POWER_AVG:
		val->intval = abs(battery->rate_avg) *
				acpi_battery_ipscale(battery) * 1000;
		val->intval *= (acpi_battery_mode(battery)) ?
				(battery->voltage_now *
				acpi_battery_vscale(battery) / 1000) : 1;
		break;
	case POWER_SUPPLY_PROP_CAPACITY:
		val->intval = battery->state_of_charge;
		break;
	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
	case POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN:
		val->intval = battery->design_capacity *
			acpi_battery_scale(battery) * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_FULL:
	case POWER_SUPPLY_PROP_ENERGY_FULL:
		val->intval = battery->full_charge_capacity *
			acpi_battery_scale(battery) * 1000;
		break;
	case POWER_SUPPLY_PROP_CHARGE_NOW:
	case POWER_SUPPLY_PROP_ENERGY_NOW:
		val->intval = battery->capacity_now *
				acpi_battery_scale(battery) * 1000;
		break;
	case POWER_SUPPLY_PROP_TEMP:
		val->intval = battery->temp_now - 2730;	// dK -> dC
		break;
	case POWER_SUPPLY_PROP_MODEL_NAME:
		val->strval = battery->device_name;
		break;
	case POWER_SUPPLY_PROP_MANUFACTURER:
		val->strval = battery->manufacturer_name;
		break;
	default:
		return -EINVAL;
	}
	return 0;
}

static enum power_supply_property sbs_ac_props[] = {
	POWER_SUPPLY_PROP_ONLINE,
};

static enum power_supply_property sbs_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_CURRENT_AVG,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
	POWER_SUPPLY_PROP_CHARGE_FULL,
	POWER_SUPPLY_PROP_CHARGE_NOW,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_MODEL_NAME,
	POWER_SUPPLY_PROP_MANUFACTURER,
};

static enum power_supply_property sbs_energy_battery_props[] = {
	POWER_SUPPLY_PROP_STATUS,
	POWER_SUPPLY_PROP_PRESENT,
	POWER_SUPPLY_PROP_TECHNOLOGY,
	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
	POWER_SUPPLY_PROP_VOLTAGE_NOW,
	POWER_SUPPLY_PROP_CURRENT_NOW,
	POWER_SUPPLY_PROP_CURRENT_AVG,
	POWER_SUPPLY_PROP_POWER_NOW,
	POWER_SUPPLY_PROP_POWER_AVG,
	POWER_SUPPLY_PROP_CAPACITY,
	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
	POWER_SUPPLY_PROP_ENERGY_FULL,
	POWER_SUPPLY_PROP_ENERGY_NOW,
	POWER_SUPPLY_PROP_TEMP,
	POWER_SUPPLY_PROP_MODEL_NAME,
	POWER_SUPPLY_PROP_MANUFACTURER,
};

static const struct power_supply_desc acpi_sbs_charger_desc = {
	.name		= "sbs-charger",
	.type		= POWER_SUPPLY_TYPE_MAINS,
	.properties	= sbs_ac_props,
	.num_properties	= ARRAY_SIZE(sbs_ac_props),
	.get_property	= sbs_get_ac_property,
};

/* --------------------------------------------------------------------------
                            Smart Battery System Management
   -------------------------------------------------------------------------- */

struct acpi_battery_reader {
	u8 command;		/* command for battery */
	u8 mode;		/* word or block? */
	size_t offset;		/* offset inside struct acpi_sbs_battery */
};

static struct acpi_battery_reader info_readers[] = {
	{0x01, SMBUS_READ_WORD, offsetof(struct acpi_battery, alarm_capacity)},
	{0x03, SMBUS_READ_WORD, offsetof(struct acpi_battery, mode)},
	{0x10, SMBUS_READ_WORD, offsetof(struct acpi_battery, full_charge_capacity)},
	{0x17, SMBUS_READ_WORD, offsetof(struct acpi_battery, cycle_count)},
	{0x18, SMBUS_READ_WORD, offsetof(struct acpi_battery, design_capacity)},
	{0x19, SMBUS_READ_WORD, offsetof(struct acpi_battery, design_voltage)},
	{0x1a, SMBUS_READ_WORD, offsetof(struct acpi_battery, spec)},
	{0x1c, SMBUS_READ_WORD, offsetof(struct acpi_battery, serial_number)},
	{0x20, SMBUS_READ_BLOCK, offsetof(struct acpi_battery, manufacturer_name)},
	{0x21, SMBUS_READ_BLOCK, offsetof(struct acpi_battery, device_name)},
	{0x22, SMBUS_READ_BLOCK, offsetof(struct acpi_battery, device_chemistry)},
};

static struct acpi_battery_reader state_readers[] = {
	{0x08, SMBUS_READ_WORD, offsetof(struct acpi_battery, temp_now)},
	{0x09, SMBUS_READ_WORD, offsetof(struct acpi_battery, voltage_now)},
	{0x0a, SMBUS_READ_WORD, offsetof(struct acpi_battery, rate_now)},
	{0x0b, SMBUS_READ_WORD, offsetof(struct acpi_battery, rate_avg)},
	{0x0f, SMBUS_READ_WORD, offsetof(struct acpi_battery, capacity_now)},
	{0x0e, SMBUS_READ_WORD, offsetof(struct acpi_battery, state_of_charge)},
	{0x16, SMBUS_READ_WORD, offsetof(struct acpi_battery, state)},
};

static int acpi_manager_get_info(struct acpi_sbs *sbs)
{
	int result = 0;
	u16 battery_system_info;

	result = acpi_smbus_read(sbs->hc, SMBUS_READ_WORD, ACPI_SBS_MANAGER,
				 0x04, (u8 *)&battery_system_info);
	if (!result)
		sbs->batteries_supported = battery_system_info & 0x000f;
	return result;
}

static int acpi_battery_get_info(struct acpi_battery *battery)
{
	int i, result = 0;

	for (i = 0; i < ARRAY_SIZE(info_readers); ++i) {
		result = acpi_smbus_read(battery->sbs->hc,
					 info_readers[i].mode,
					 ACPI_SBS_BATTERY,
					 info_readers[i].command,
					 (u8 *) battery +
						info_readers[i].offset);
		if (result)
			break;
	}
	return result;
}

static int acpi_battery_get_state(struct acpi_battery *battery)
{
	int i, result = 0;

	if (battery->update_time &&
	    time_before(jiffies, battery->update_time +
				msecs_to_jiffies(cache_time)))
		return 0;
	for (i = 0; i < ARRAY_SIZE(state_readers); ++i) {
		result = acpi_smbus_read(battery->sbs->hc,
					 state_readers[i].mode,
					 ACPI_SBS_BATTERY,
					 state_readers[i].command,
				         (u8 *)battery +
						state_readers[i].offset);
		if (result)
			goto end;
	}
      end:
	battery->update_time = jiffies;
	return result;
}

static int acpi_battery_get_alarm(struct acpi_battery *battery)
{
	return acpi_smbus_read(battery->sbs->hc, SMBUS_READ_WORD,
				 ACPI_SBS_BATTERY, 0x01,
				 (u8 *)&battery->alarm_capacity);
}

static int acpi_battery_set_alarm(struct acpi_battery *battery)
{
	struct acpi_sbs *sbs = battery->sbs;
	u16 value, sel = 1 << (battery->id + 12);

	int ret;


	if (sbs->manager_present) {
		ret = acpi_smbus_read(sbs->hc, SMBUS_READ_WORD, ACPI_SBS_MANAGER,
				0x01, (u8 *)&value);
		if (ret)
			goto end;
		if ((value & 0xf000) != sel) {
			value &= 0x0fff;
			value |= sel;
			ret = acpi_smbus_write(sbs->hc, SMBUS_WRITE_WORD,
					 ACPI_SBS_MANAGER,
					 0x01, (u8 *)&value, 2);
			if (ret)
				goto end;
		}
	}
	ret = acpi_smbus_write(sbs->hc, SMBUS_WRITE_WORD, ACPI_SBS_BATTERY,
				0x01, (u8 *)&battery->alarm_capacity, 2);
      end:
	return ret;
}

static int acpi_ac_get_present(struct acpi_sbs *sbs)
{
	int result;
	u16 status;

	result = acpi_smbus_read(sbs->hc, SMBUS_READ_WORD, ACPI_SBS_CHARGER,
				 0x13, (u8 *) & status);

	if (result)
		return result;

	/*
	 * The spec requires that bit 4 always be 1. If it's not set, assume
	 * that the implementation doesn't support an SBS charger.
	 *
	 * And on some MacBooks a status of 0xffff is always returned, no
	 * matter whether the charger is plugged in or not, which is also
	 * wrong, so ignore the SBS charger for those too.
	 */
	if (!((status >> 4) & 0x1) || status == 0xffff)
		return -ENODEV;

	sbs->charger_present = (status >> 15) & 0x1;
	return 0;
}

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));
	acpi_battery_get_alarm(battery);
	return sprintf(buf, "%d\n", battery->alarm_capacity *
				acpi_battery_scale(battery) * 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_capacity = x /
			(1000 * acpi_battery_scale(battery));
	if (battery->present)
		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,
};

/* --------------------------------------------------------------------------
                                 Driver Interface
   -------------------------------------------------------------------------- */
static int acpi_battery_read(struct acpi_battery *battery)
{
	int result = 0, saved_present = battery->present;
	u16 state;

	if (battery->sbs->manager_present) {
		result = acpi_smbus_read(battery->sbs->hc, SMBUS_READ_WORD,
				ACPI_SBS_MANAGER, 0x01, (u8 *)&state);
		if (!result)
			battery->present = state & (1 << battery->id);
		state &= 0x0fff;
		state |= 1 << (battery->id + 12);
		acpi_smbus_write(battery->sbs->hc, SMBUS_WRITE_WORD,
				  ACPI_SBS_MANAGER, 0x01, (u8 *)&state, 2);
	} else if (battery->id == 0)
		battery->present = 1;

	if (result || !battery->present)
		return result;

	if (saved_present != battery->present) {
		battery->update_time = 0;
		result = acpi_battery_get_info(battery);
		if (result) {
			battery->present = 0;
			return result;
		}
	}
	result = acpi_battery_get_state(battery);
	if (result)
		battery->present = 0;
	return result;
}

/* Smart Battery */
static int acpi_battery_add(struct acpi_sbs *sbs, int id)
{
	struct acpi_battery *battery = &sbs->battery[id];
	struct power_supply_config psy_cfg = { .drv_data = battery, };
	int result;

	battery->id = id;
	battery->sbs = sbs;
	result = acpi_battery_read(battery);
	if (result)
		return result;

	sprintf(battery->name, ACPI_BATTERY_DIR_NAME, id);
	battery->bat_desc.name = battery->name;
	battery->bat_desc.type = POWER_SUPPLY_TYPE_BATTERY;
	if (!acpi_battery_mode(battery)) {
		battery->bat_desc.properties = sbs_charge_battery_props;
		battery->bat_desc.num_properties =
		    ARRAY_SIZE(sbs_charge_battery_props);
	} else {
		battery->bat_desc.properties = sbs_energy_battery_props;
		battery->bat_desc.num_properties =
		    ARRAY_SIZE(sbs_energy_battery_props);
	}
	battery->bat_desc.get_property = acpi_sbs_battery_get_property;
	battery->bat = power_supply_register(&sbs->device->dev,
					&battery->bat_desc, &psy_cfg);
	if (IS_ERR(battery->bat)) {
		result = PTR_ERR(battery->bat);
		battery->bat = NULL;
		goto end;
	}

	result = device_create_file(&battery->bat->dev, &alarm_attr);
	if (result)
		goto end;
	battery->have_sysfs_alarm = 1;
      end:
	printk(KERN_INFO PREFIX "%s [%s]: Battery Slot [%s] (battery %s)\n",
	       ACPI_SBS_DEVICE_NAME, acpi_device_bid(sbs->device),
	       battery->name, battery->present ? "present" : "absent");
	return result;
}

static void acpi_battery_remove(struct acpi_sbs *sbs, int id)
{
	struct acpi_battery *battery = &sbs->battery[id];

	if (battery->bat) {
		if (battery->have_sysfs_alarm)
			device_remove_file(&battery->bat->dev, &alarm_attr);
		power_supply_unregister(battery->bat);
	}
}

static int acpi_charger_add(struct acpi_sbs *sbs)
{
	int result;
	struct power_supply_config psy_cfg = { .drv_data = sbs, };

	result = acpi_ac_get_present(sbs);
	if (result)
		goto end;

	sbs->charger_exists = 1;
	sbs->charger = power_supply_register(&sbs->device->dev,
					&acpi_sbs_charger_desc, &psy_cfg);
	if (IS_ERR(sbs->charger)) {
		result = PTR_ERR(sbs->charger);
		sbs->charger = NULL;
	}
	printk(KERN_INFO PREFIX "%s [%s]: AC Adapter [%s] (%s)\n",
	       ACPI_SBS_DEVICE_NAME, acpi_device_bid(sbs->device),
	       ACPI_AC_DIR_NAME, sbs->charger_present ? "on-line" : "off-line");
      end:
	return result;
}

static void acpi_charger_remove(struct acpi_sbs *sbs)
{
	if (sbs->charger)
		power_supply_unregister(sbs->charger);
}

static void acpi_sbs_callback(void *context)
{
	int id;
	struct acpi_sbs *sbs = context;
	struct acpi_battery *bat;
	u8 saved_charger_state = sbs->charger_present;
	u8 saved_battery_state;

	if (sbs->charger_exists) {
		acpi_ac_get_present(sbs);
		if (sbs->charger_present != saved_charger_state)
			kobject_uevent(&sbs->charger->dev.kobj, KOBJ_CHANGE);
	}

	if (sbs->manager_present) {
		for (id = 0; id < MAX_SBS_BAT; ++id) {
			if (!(sbs->batteries_supported & (1 << id)))
				continue;
			bat = &sbs->battery[id];
			saved_battery_state = bat->present;
			acpi_battery_read(bat);
			if (saved_battery_state == bat->present)
				continue;
			kobject_uevent(&bat->bat->dev.kobj, KOBJ_CHANGE);
		}
	}
}

static int acpi_sbs_add(struct acpi_device *device)
{
	struct acpi_sbs *sbs;
	int result = 0;
	int id;

	sbs = kzalloc(sizeof(struct acpi_sbs), GFP_KERNEL);
	if (!sbs) {
		result = -ENOMEM;
		goto end;
	}

	mutex_init(&sbs->lock);

	sbs->hc = acpi_driver_data(device->parent);
	sbs->device = device;
	strcpy(acpi_device_name(device), ACPI_SBS_DEVICE_NAME);
	strcpy(acpi_device_class(device), ACPI_SBS_CLASS);
	device->driver_data = sbs;

	result = acpi_charger_add(sbs);
	if (result && result != -ENODEV)
		goto end;

	result = 0;

	if (!x86_apple_machine) {
		result = acpi_manager_get_info(sbs);
		if (!result) {
			sbs->manager_present = 1;
			for (id = 0; id < MAX_SBS_BAT; ++id)
				if ((sbs->batteries_supported & (1 << id)))
					acpi_battery_add(sbs, id);
		}
	}

	if (!sbs->manager_present)
		acpi_battery_add(sbs, 0);

	acpi_smbus_register_callback(sbs->hc, acpi_sbs_callback, sbs);
      end:
	if (result)
		acpi_sbs_remove(device);
	return result;
}

static int acpi_sbs_remove(struct acpi_device *device)
{
	struct acpi_sbs *sbs;
	int id;

	if (!device)
		return -EINVAL;
	sbs = acpi_driver_data(device);
	if (!sbs)
		return -EINVAL;
	mutex_lock(&sbs->lock);
	acpi_smbus_unregister_callback(sbs->hc);
	for (id = 0; id < MAX_SBS_BAT; ++id)
		acpi_battery_remove(sbs, id);
	acpi_charger_remove(sbs);
	mutex_unlock(&sbs->lock);
	mutex_destroy(&sbs->lock);
	kfree(sbs);
	return 0;
}

#ifdef CONFIG_PM_SLEEP
static int acpi_sbs_resume(struct device *dev)
{
	struct acpi_sbs *sbs;
	if (!dev)
		return -EINVAL;
	sbs = to_acpi_device(dev)->driver_data;
	acpi_sbs_callback(sbs);
	return 0;
}
#else
#define acpi_sbs_resume NULL
#endif

static SIMPLE_DEV_PM_OPS(acpi_sbs_pm, NULL, acpi_sbs_resume);

static struct acpi_driver acpi_sbs_driver = {
	.name = "sbs",
	.class = ACPI_SBS_CLASS,
	.ids = sbs_device_ids,
	.ops = {
		.add = acpi_sbs_add,
		.remove = acpi_sbs_remove,
		},
	.drv.pm = &acpi_sbs_pm,
};

static int __init acpi_sbs_init(void)
{
	int result = 0;

	if (acpi_disabled)
		return -ENODEV;

	result = acpi_bus_register_driver(&acpi_sbs_driver);
	if (result < 0)
		return -ENODEV;

	return 0;
}

static void __exit acpi_sbs_exit(void)
{
	acpi_bus_unregister_driver(&acpi_sbs_driver);
	return;
}

module_init(acpi_sbs_init);
module_exit(acpi_sbs_exit);