This driver exposes ACPI 4.0 compliant power meters as hardware monitoring devices. Signed-off-by: Darrick J. Wong <djwong at us.ibm.com> --- Documentation/hwmon/acpi_power_meter | 25 + drivers/acpi/Kconfig | 12 + drivers/acpi/Makefile | 1 drivers/acpi/power_meter.c | 776 ++++++++++++++++++++++++++++++++++ 4 files changed, 814 insertions(+), 0 deletions(-) create mode 100644 Documentation/hwmon/acpi_power_meter create mode 100644 drivers/acpi/power_meter.c diff --git a/Documentation/hwmon/acpi_power_meter b/Documentation/hwmon/acpi_power_meter new file mode 100644 index 0000000..0af2e9a --- /dev/null +++ b/Documentation/hwmon/acpi_power_meter @@ -0,0 +1,25 @@ +Kernel driver power_meter +========================= + +This driver talks to ACPI 4.0 power meters. + +Supported systems: + * Any recent system with ACPI 4.0. + Prefix: 'power_meter' + Datasheet: http://acpi.info/, section 10.4. + +Author: Darrick J. Wong + +Description +----------- + +This driver implements sensor reading support for the power meters exposed in +the ACPI 4.0 spec (Chapter 10.4). These devices have a simple set of +features--a power meter that returns average power use over a configurable +interval, an optional capping mechanism, and a couple of trip points. + +Special Features +---------------- + +The power[1-*]_is_battery knob indicates if the power supply is a battery. +Both power[1-*]_average_{min,max} must be set before the trip points will work. diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index 7ec7d88..8ac801d 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -82,6 +82,18 @@ config ACPI_PROCFS_POWER Say N to delete power /proc/acpi/ directories that have moved to /sys/ +config ACPI_POWER_METER + tristate "ACPI 4.0 power meter" + depends on HWMON + default m + help + This driver exposes ACPI 4.0 power meters as hardware monitoring + devices. Say Y (or M) if you have an Intel or AMD computer with + a power meter. + + To compile this driver as a module, choose M here: + the module will be called power-meter. + config ACPI_SYSFS_POWER bool "Future power /sys interface" select POWER_SUPPLY diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index 03a985b..82cd49d 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -56,6 +56,7 @@ obj-$(CONFIG_ACPI_HOTPLUG_MEMORY) += acpi_memhotplug.o obj-$(CONFIG_ACPI_BATTERY) += battery.o obj-$(CONFIG_ACPI_SBS) += sbshc.o obj-$(CONFIG_ACPI_SBS) += sbs.o +obj-$(CONFIG_ACPI_POWER_METER) += power_meter.o # processor has its own "processor." module_param namespace processor-y := processor_core.o processor_throttling.o diff --git a/drivers/acpi/power_meter.c b/drivers/acpi/power_meter.c new file mode 100644 index 0000000..9418bbd --- /dev/null +++ b/drivers/acpi/power_meter.c @@ -0,0 +1,776 @@ +/* + * A hwmon driver for ACPI 4.0 power meters + * Copyright (C) 2009 IBM + * + * Author: Darrick J. Wong <djwong at us.ibm.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/module.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/jiffies.h> +#include <linux/mutex.h> +#include <linux/kdev_t.h> +#include <linux/sched.h> +#include <linux/time.h> +#include <acpi/acpi_drivers.h> +#include <acpi/acpi_bus.h> + +#define ACPI_POWER_METER_NAME "power_meter" +ACPI_MODULE_NAME(ACPI_POWER_METER_NAME); +#define ACPI_POWER_METER_DEVICE_NAME "Power Meter" +#define ACPI_POWER_METER_CLASS "power_meter_resource" + +#define NUM_SENSORS 14 + +#define POWER_METER_CAN_MEASURE (1 << 0) +#define POWER_METER_CAN_TRIP (1 << 1) +#define POWER_METER_CAN_CAP (1 << 2) +#define POWER_METER_CAN_NOTIFY (1 << 3) +#define POWER_METER_IS_BATTERY (1 << 8) +#define UNKNOWN_HYSTERESIS 0xFFFFFFFF + +#define METER_NOTIFY_CONFIG 0x80 +#define METER_NOTIFY_TRIP 0x81 +#define METER_NOTIFY_CAP 0x82 +#define METER_NOTIFY_CAPPING 0x83 +#define METER_NOTIFY_INTERVAL 0x84 + +static struct acpi_device_id power_meter_ids[] = { + {"ACPI000D", 0}, + {"", 0}, +}; +MODULE_DEVICE_TABLE(acpi, power_meter_ids); + +struct acpi_power_meter_capabilities { + acpi_integer flags; + acpi_integer units; + acpi_integer type; + acpi_integer accuracy; + acpi_integer sampling_time; + acpi_integer min_avg_interval; + acpi_integer max_avg_interval; + acpi_integer hysteresis; + acpi_integer configurable_cap; + acpi_integer min_cap; + acpi_integer max_cap; +}; + +struct acpi_power_meter_resource { + struct acpi_device *acpi_dev; + acpi_bus_id name; + struct mutex lock; + struct device *hwmon_dev; + struct acpi_power_meter_capabilities caps; + acpi_integer power; + acpi_integer cap; + acpi_integer avg_interval; + int sensors_valid; + unsigned long sensors_last_updated; + struct sensor_device_attribute sensors[NUM_SENSORS]; + int num_sensors; + int trip[2]; +}; + +struct ro_sensor_template { + char *label; + ssize_t (*show)(struct device *dev, + struct device_attribute *devattr, + char *buf); + int index; +}; + +struct rw_sensor_template { + char *label; + ssize_t (*show)(struct device *dev, + struct device_attribute *devattr, + char *buf); + ssize_t (*set)(struct device *dev, + struct device_attribute *devattr, + const char *buf, size_t count); + int index; +}; + +/* Averaging interval */ +static int update_avg_interval(struct acpi_power_meter_resource *resource) +{ + unsigned long long data; + acpi_status status; + + status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI", + NULL, &data); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GAI")); + return -ENODEV; + } + + resource->avg_interval = data; + return 0; +} + +static ssize_t show_avg_interval(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + + mutex_lock(&resource->lock); + update_avg_interval(resource); + mutex_unlock(&resource->lock); + + return sprintf(buf, "%llu\n", resource->avg_interval); +} + +static ssize_t set_avg_interval(struct device *dev, + struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + union acpi_object arg0 = { ACPI_TYPE_INTEGER }; + struct acpi_object_list args = { 1, &arg0 }; + int res; + unsigned long temp; + unsigned long long data; + acpi_status status; + + res = strict_strtoul(buf, 10, &temp); + if (res) + return res; + + if (temp > resource->caps.max_avg_interval || + temp < resource->caps.min_avg_interval) + return -EINVAL; + arg0.integer.value = temp; + + mutex_lock(&resource->lock); + status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI", + &args, &data); + if (!ACPI_FAILURE(status)) + resource->avg_interval = temp; + mutex_unlock(&resource->lock); + + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PAI")); + return -EINVAL; + } + + if (data) + return -EINVAL; + + return count; +} + +/* Cap functions */ +static int update_cap(struct acpi_power_meter_resource *resource) +{ + unsigned long long data; + acpi_status status; + + status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL", + NULL, &data); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GHL")); + return -ENODEV; + } + + resource->cap = data; + return 0; +} + +static ssize_t show_cap(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + + mutex_lock(&resource->lock); + update_cap(resource); + mutex_unlock(&resource->lock); + + return sprintf(buf, "%llu\n", resource->cap * 1000); +} + +static ssize_t set_cap(struct device *dev, struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + union acpi_object arg0 = { ACPI_TYPE_INTEGER }; + struct acpi_object_list args = { 1, &arg0 }; + int res; + unsigned long temp; + unsigned long long data; + acpi_status status; + + res = strict_strtoul(buf, 10, &temp); + if (res) + return res; + + temp /= 1000; + if (temp > resource->caps.max_cap || temp < resource->caps.min_cap) + return -EINVAL; + arg0.integer.value = temp; + + mutex_lock(&resource->lock); + status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL", + &args, &data); + if (!ACPI_FAILURE(status)) + resource->cap = temp; + mutex_unlock(&resource->lock); + + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SHL")); + return -EINVAL; + } + + if (data) + return -EINVAL; + + return count; +} + +/* Power meter trip points */ +static int set_acpi_trip(struct acpi_power_meter_resource *resource) +{ + union acpi_object arg_objs[] = { + {ACPI_TYPE_INTEGER}, + {ACPI_TYPE_INTEGER} + }; + struct acpi_object_list args = { 2, arg_objs }; + unsigned long long data; + acpi_status status; + + /* Both trip levels must be set */ + if (resource->trip[0] < 0 || resource->trip[1] < 0) + return 0; + + /* This driver stores min, max; ACPI wants max, min. */ + arg_objs[0].integer.value = resource->trip[1]; + arg_objs[1].integer.value = resource->trip[0]; + + status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP", + &args, &data); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTP")); + return -EINVAL; + } + + return data; +} + +static ssize_t set_trip(struct device *dev, struct device_attribute *devattr, + const char *buf, size_t count) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + int res; + unsigned long temp; + + res = strict_strtoul(buf, 10, &temp); + if (res) + return res; + + temp /= 1000; + if (temp < 0) + return -EINVAL; + + mutex_lock(&resource->lock); + resource->trip[attr->index - 7] = temp; + res = set_acpi_trip(resource); + mutex_unlock(&resource->lock); + + if (res) + return res; + + return count; +} + +/* Power meter */ +static int update_meter(struct acpi_power_meter_resource *resource) +{ + unsigned long long data; + acpi_status status; + unsigned long local_jiffies = jiffies; + + if (time_before(local_jiffies, resource->sensors_last_updated + + msecs_to_jiffies(resource->caps.sampling_time)) && + resource->sensors_valid) + return 0; + + status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM", + NULL, &data); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMM")); + return -ENODEV; + } + + resource->power = data; + resource->sensors_valid = 1; + resource->sensors_last_updated = jiffies; + return 0; +} + +static ssize_t show_power(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + + mutex_lock(&resource->lock); + update_meter(resource); + mutex_unlock(&resource->lock); + + return sprintf(buf, "%llu\n", resource->power * 1000); +} + +/* Miscellaneous */ +static ssize_t show_val(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr); + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + acpi_integer val = 0; + + switch (attr->index) { + case 0: + val = resource->caps.min_avg_interval; + break; + case 1: + val = resource->caps.max_avg_interval; + break; + case 2: + val = resource->caps.min_cap * 1000; + break; + case 3: + val = resource->caps.max_cap * 1000; + break; + case 4: + if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS) + return sprintf(buf, "unknown\n"); + + val = resource->caps.hysteresis * 1000; + break; + case 5: + if (resource->caps.flags & POWER_METER_IS_BATTERY) + val = 1; + else + val = 0; + break; + case 6: + if (resource->power > resource->cap) + val = 1; + else + val = 0; + break; + case 7: + case 8: + if (resource->trip[attr->index - 7] < 0) + return sprintf(buf, "unknown\n"); + + val = resource->trip[attr->index - 7] * 1000; + break; + default: + BUG(); + } + + return sprintf(buf, "%llu\n", val); +} + +static ssize_t show_accuracy(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + struct acpi_device *acpi_dev = to_acpi_device(dev); + struct acpi_power_meter_resource *resource = acpi_dev->driver_data; + unsigned int acc = resource->caps.accuracy; + + return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000); +} + +static ssize_t show_name(struct device *dev, + struct device_attribute *devattr, + char *buf) +{ + return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME); +} + +/* Sensor descriptions. If you add a sensor, update NUM_SENSORS above! */ +static struct ro_sensor_template meter_ro_attrs[] = { +{"power1_average", show_power, 0}, +{"power1_accuracy", show_accuracy, 0}, +{"power1_average_interval_min", show_val, 0}, +{"power1_average_interval_max", show_val, 1}, +{"power1_is_battery", show_val, 5}, +{NULL, NULL, 0}, +}; + +static struct rw_sensor_template meter_rw_attrs[] = { +{"power1_average_interval", show_avg_interval, set_avg_interval, 0}, +{NULL, NULL, NULL, 0}, +}; + +static struct ro_sensor_template misc_cap_attrs[] = { +{"power1_cap_min", show_val, 2}, +{"power1_cap_max", show_val, 3}, +{"power1_cap_hyst", show_val, 4}, +{"power1_alarm", show_val, 6}, +{NULL, NULL, 0}, +}; + +static struct ro_sensor_template ro_cap_attrs[] = { +{"power1_cap", show_cap, 0}, +{NULL, NULL, 0}, +}; + +static struct rw_sensor_template rw_cap_attrs[] = { +{"power1_cap", show_cap, set_cap, 0}, +{NULL, NULL, NULL, 0}, +}; + +static struct rw_sensor_template trip_attrs[] = { +{"power1_average_min", show_val, set_trip, 7}, +{"power1_average_max", show_val, set_trip, 8}, +{NULL, NULL, NULL, 0}, +}; + +static struct ro_sensor_template misc_attrs[] = { +{"name", show_name, 0}, +{NULL, NULL, 0}, +}; + +/* Registration and deregistration */ +static int register_ro_attrs(struct acpi_power_meter_resource *resource, + struct ro_sensor_template *ro) +{ + struct device *dev = &resource->acpi_dev->dev; + struct sensor_device_attribute *sensors = + &resource->sensors[resource->num_sensors]; + int res; + + while (ro->label) { + sensors->dev_attr.attr.name = ro->label; + sensors->dev_attr.attr.mode = S_IRUGO; + sensors->dev_attr.show = ro->show; + sensors->index = ro->index; + + res = device_create_file(dev, &sensors->dev_attr); + if (res) { + sensors->dev_attr.attr.name = NULL; + goto error; + } + sensors++; + resource->num_sensors++; + ro++; + } + +error: + return res; +} + +static int register_rw_attrs(struct acpi_power_meter_resource *resource, + struct rw_sensor_template *rw) +{ + struct device *dev = &resource->acpi_dev->dev; + struct sensor_device_attribute *sensors = + &resource->sensors[resource->num_sensors]; + int res; + + while (rw->label) { + sensors->dev_attr.attr.name = rw->label; + sensors->dev_attr.attr.mode = S_IRUGO | S_IWUSR; + sensors->dev_attr.show = rw->show; + sensors->dev_attr.store = rw->set; + sensors->index = rw->index; + + res = device_create_file(dev, &sensors->dev_attr); + if (res) { + sensors->dev_attr.attr.name = NULL; + goto error; + } + sensors++; + resource->num_sensors++; + rw++; + } + +error: + return res; +} + +static void remove_attrs(struct acpi_power_meter_resource *resource) +{ + int i; + + for (i = 0; i < resource->num_sensors; i++) { + if (!resource->sensors[i].dev_attr.attr.name) + continue; + device_remove_file(&resource->acpi_dev->dev, + &resource->sensors[i].dev_attr); + } + + resource->num_sensors = 0; +} + +static int setup_attrs(struct acpi_power_meter_resource *resource) +{ + int res = 0; + + if (resource->caps.flags & POWER_METER_CAN_MEASURE) { + res = register_ro_attrs(resource, meter_ro_attrs); + if (res) + goto error; + res = register_rw_attrs(resource, meter_rw_attrs); + if (res) + goto error; + } + + if (resource->caps.flags & POWER_METER_CAN_CAP) { + if (resource->caps.configurable_cap) { + res = register_rw_attrs(resource, rw_cap_attrs); + if (res) + goto error; + } else { + res = register_ro_attrs(resource, ro_cap_attrs); + if (res) + goto error; + } + res = register_ro_attrs(resource, misc_cap_attrs); + if (res) + goto error; + } + + if (resource->caps.flags & POWER_METER_CAN_TRIP) { + res = register_rw_attrs(resource, trip_attrs); + if (res) + goto error; + } + + res = register_ro_attrs(resource, misc_attrs); + if (res) + goto error; + + return res; +error: + remove_attrs(resource); + return res; +} + +static int read_capabilities(struct acpi_power_meter_resource *resource) +{ + int res = 0; + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + struct acpi_buffer state = { 0, NULL }; + struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" }; + union acpi_object *pss; + acpi_status status; + + status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL, + &buffer); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC")); + return -ENODEV; + } + + pss = buffer.pointer; + if (!pss || + pss->type != ACPI_TYPE_PACKAGE || + pss->package.count != 14) { + dev_err(&resource->acpi_dev->dev, PREFIX "Invalid _PMC data\n"); + res = -EFAULT; + goto end; + } + + state.length = sizeof(struct acpi_power_meter_capabilities); + state.pointer = &resource->caps; + + status = acpi_extract_package(pss, &format, &state); + if (ACPI_FAILURE(status)) { + ACPI_EXCEPTION((AE_INFO, status, "Invalid data")); + res = -EFAULT; + goto end; + } + + if (resource->caps.units) { + dev_err(&resource->acpi_dev->dev, PREFIX "Unknown unit %llu.\n", + resource->caps.units); + res = -EINVAL; + goto end; + } + + dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n"); +end: + kfree(buffer.pointer); + return res; +} + +/* Handle ACPI event notifications */ +static void acpi_power_meter_notify(struct acpi_device *device, u32 event) +{ + struct acpi_power_meter_resource *resource; + int res; + + if (!device || !acpi_driver_data(device)) + return; + + resource = acpi_driver_data(device); + + mutex_lock(&resource->lock); + switch (event) { + case METER_NOTIFY_CONFIG: + res = read_capabilities(resource); + if (res) + break; + + remove_attrs(resource); + setup_attrs(resource); + break; + case METER_NOTIFY_TRIP: + update_meter(resource); + break; + case METER_NOTIFY_CAP: + update_cap(resource); + break; + case METER_NOTIFY_INTERVAL: + update_avg_interval(resource); + break; + case METER_NOTIFY_CAPPING: + dev_info(&device->dev, "Capping in progress.\n"); + break; + default: + BUG(); + } + mutex_unlock(&resource->lock); +} + +static int acpi_power_meter_add(struct acpi_device *device) +{ + int res; + struct acpi_power_meter_resource *resource; + + if (!device) + return -EINVAL; + + resource = kzalloc(sizeof(struct acpi_power_meter_resource), + GFP_KERNEL); + if (!resource) + return -ENOMEM; + + resource->sensors_valid = 0; + resource->acpi_dev = device; + mutex_init(&resource->lock); + strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME); + strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS); + device->driver_data = resource; + + res = read_capabilities(resource); + if (res) + goto exit_free; + + resource->trip[0] = resource->trip[1] = -1; + + res = setup_attrs(resource); + if (res) + goto exit_free; + + resource->hwmon_dev = hwmon_device_register(&device->dev); + if (IS_ERR(resource->hwmon_dev)) { + res = PTR_ERR(resource->hwmon_dev); + goto exit_remove; + } + + res = 0; + goto exit; + +exit_remove: + remove_attrs(resource); +exit_free: + kfree(resource); +exit: + return res; +} + +static int acpi_power_meter_remove(struct acpi_device *device, int type) +{ + struct acpi_power_meter_resource *resource; + + if (!device || !acpi_driver_data(device)) + return -EINVAL; + + resource = acpi_driver_data(device); + hwmon_device_unregister(resource->hwmon_dev); + + remove_attrs(resource); + + kfree(resource); + return 0; +} + +static int acpi_power_meter_resume(struct acpi_device *device) +{ + struct acpi_power_meter_resource *resource; + + if (!device || !acpi_driver_data(device)) + return -EINVAL; + + resource = acpi_driver_data(device); + read_capabilities(resource); + + return 0; +} + +static struct acpi_driver acpi_power_meter_driver = { + .name = "power_meter", + .class = ACPI_POWER_METER_CLASS, + .ids = power_meter_ids, + .ops = { + .add = acpi_power_meter_add, + .remove = acpi_power_meter_remove, + .resume = acpi_power_meter_resume, + .notify = acpi_power_meter_notify, + }, +}; + +/* Module init/exit routines */ + +static int __init acpi_power_meter_init(void) +{ + int result; + + result = acpi_bus_register_driver(&acpi_power_meter_driver); + if (result < 0) + return -ENODEV; + + return 0; +} + +static void __exit acpi_power_meter_exit(void) +{ + acpi_bus_unregister_driver(&acpi_power_meter_driver); +} + +MODULE_AUTHOR("Darrick J. Wong <djwong at us.ibm.com>"); +MODULE_DESCRIPTION("ACPI 4.0 power meter driver"); +MODULE_LICENSE("GPL"); + +module_init(acpi_power_meter_init); +module_exit(acpi_power_meter_exit);
