2 * A hwmon driver for ACPI 4.0 power meters
3 * Copyright (C) 2009 IBM
5 * Author: Darrick J. Wong <djwong@us.ibm.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include <linux/module.h>
23 #include <linux/hwmon.h>
24 #include <linux/hwmon-sysfs.h>
25 #include <linux/jiffies.h>
26 #include <linux/mutex.h>
27 #include <linux/dmi.h>
28 #include <linux/slab.h>
29 #include <linux/kdev_t.h>
30 #include <linux/sched.h>
31 #include <linux/time.h>
32 #include <acpi/acpi_drivers.h>
33 #include <acpi/acpi_bus.h>
35 #define ACPI_POWER_METER_NAME "power_meter"
36 ACPI_MODULE_NAME(ACPI_POWER_METER_NAME);
37 #define ACPI_POWER_METER_DEVICE_NAME "Power Meter"
38 #define ACPI_POWER_METER_CLASS "pwr_meter_resource"
40 #define NUM_SENSORS 17
42 #define POWER_METER_CAN_MEASURE (1 << 0)
43 #define POWER_METER_CAN_TRIP (1 << 1)
44 #define POWER_METER_CAN_CAP (1 << 2)
45 #define POWER_METER_CAN_NOTIFY (1 << 3)
46 #define POWER_METER_IS_BATTERY (1 << 8)
47 #define UNKNOWN_HYSTERESIS 0xFFFFFFFF
49 #define METER_NOTIFY_CONFIG 0x80
50 #define METER_NOTIFY_TRIP 0x81
51 #define METER_NOTIFY_CAP 0x82
52 #define METER_NOTIFY_CAPPING 0x83
53 #define METER_NOTIFY_INTERVAL 0x84
55 #define POWER_AVERAGE_NAME "power1_average"
56 #define POWER_CAP_NAME "power1_cap"
57 #define POWER_AVG_INTERVAL_NAME "power1_average_interval"
58 #define POWER_ALARM_NAME "power1_alarm"
60 static int cap_in_hardware;
61 static bool force_cap_on;
63 static int can_cap_in_hardware(void)
65 return force_cap_on || cap_in_hardware;
68 static const struct acpi_device_id power_meter_ids[] = {
72 MODULE_DEVICE_TABLE(acpi, power_meter_ids);
74 struct acpi_power_meter_capabilities {
88 struct acpi_power_meter_resource {
89 struct acpi_device *acpi_dev;
92 struct device *hwmon_dev;
93 struct acpi_power_meter_capabilities caps;
94 acpi_string model_number;
95 acpi_string serial_number;
101 unsigned long sensors_last_updated;
102 struct sensor_device_attribute sensors[NUM_SENSORS];
105 int num_domain_devices;
106 struct acpi_device **domain_devices;
107 struct kobject *holders_dir;
110 struct sensor_template {
112 ssize_t (*show)(struct device *dev,
113 struct device_attribute *devattr,
115 ssize_t (*set)(struct device *dev,
116 struct device_attribute *devattr,
117 const char *buf, size_t count);
121 /* Averaging interval */
122 static int update_avg_interval(struct acpi_power_meter_resource *resource)
124 unsigned long long data;
127 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
129 if (ACPI_FAILURE(status)) {
130 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GAI"));
134 resource->avg_interval = data;
138 static ssize_t show_avg_interval(struct device *dev,
139 struct device_attribute *devattr,
142 struct acpi_device *acpi_dev = to_acpi_device(dev);
143 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
145 mutex_lock(&resource->lock);
146 update_avg_interval(resource);
147 mutex_unlock(&resource->lock);
149 return sprintf(buf, "%llu\n", resource->avg_interval);
152 static ssize_t set_avg_interval(struct device *dev,
153 struct device_attribute *devattr,
154 const char *buf, size_t count)
156 struct acpi_device *acpi_dev = to_acpi_device(dev);
157 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
158 union acpi_object arg0 = { ACPI_TYPE_INTEGER };
159 struct acpi_object_list args = { 1, &arg0 };
162 unsigned long long data;
165 res = kstrtoul(buf, 10, &temp);
169 if (temp > resource->caps.max_avg_interval ||
170 temp < resource->caps.min_avg_interval)
172 arg0.integer.value = temp;
174 mutex_lock(&resource->lock);
175 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
177 if (!ACPI_FAILURE(status))
178 resource->avg_interval = temp;
179 mutex_unlock(&resource->lock);
181 if (ACPI_FAILURE(status)) {
182 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PAI"));
186 /* _PAI returns 0 on success, nonzero otherwise */
194 static int update_cap(struct acpi_power_meter_resource *resource)
196 unsigned long long data;
199 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
201 if (ACPI_FAILURE(status)) {
202 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GHL"));
206 resource->cap = data;
210 static ssize_t show_cap(struct device *dev,
211 struct device_attribute *devattr,
214 struct acpi_device *acpi_dev = to_acpi_device(dev);
215 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
217 mutex_lock(&resource->lock);
218 update_cap(resource);
219 mutex_unlock(&resource->lock);
221 return sprintf(buf, "%llu\n", resource->cap * 1000);
224 static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
225 const char *buf, size_t count)
227 struct acpi_device *acpi_dev = to_acpi_device(dev);
228 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
229 union acpi_object arg0 = { ACPI_TYPE_INTEGER };
230 struct acpi_object_list args = { 1, &arg0 };
233 unsigned long long data;
236 res = kstrtoul(buf, 10, &temp);
240 temp = DIV_ROUND_CLOSEST(temp, 1000);
241 if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
243 arg0.integer.value = temp;
245 mutex_lock(&resource->lock);
246 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
248 if (!ACPI_FAILURE(status))
249 resource->cap = temp;
250 mutex_unlock(&resource->lock);
252 if (ACPI_FAILURE(status)) {
253 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SHL"));
257 /* _SHL returns 0 on success, nonzero otherwise */
264 /* Power meter trip points */
265 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
267 union acpi_object arg_objs[] = {
271 struct acpi_object_list args = { 2, arg_objs };
272 unsigned long long data;
275 /* Both trip levels must be set */
276 if (resource->trip[0] < 0 || resource->trip[1] < 0)
279 /* This driver stores min, max; ACPI wants max, min. */
280 arg_objs[0].integer.value = resource->trip[1];
281 arg_objs[1].integer.value = resource->trip[0];
283 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
285 if (ACPI_FAILURE(status)) {
286 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTP"));
290 /* _PTP returns 0 on success, nonzero otherwise */
297 static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
298 const char *buf, size_t count)
300 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
301 struct acpi_device *acpi_dev = to_acpi_device(dev);
302 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
306 res = kstrtoul(buf, 10, &temp);
310 temp = DIV_ROUND_CLOSEST(temp, 1000);
312 mutex_lock(&resource->lock);
313 resource->trip[attr->index - 7] = temp;
314 res = set_acpi_trip(resource);
315 mutex_unlock(&resource->lock);
324 static int update_meter(struct acpi_power_meter_resource *resource)
326 unsigned long long data;
328 unsigned long local_jiffies = jiffies;
330 if (time_before(local_jiffies, resource->sensors_last_updated +
331 msecs_to_jiffies(resource->caps.sampling_time)) &&
332 resource->sensors_valid)
335 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
337 if (ACPI_FAILURE(status)) {
338 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMM"));
342 resource->power = data;
343 resource->sensors_valid = 1;
344 resource->sensors_last_updated = jiffies;
348 static ssize_t show_power(struct device *dev,
349 struct device_attribute *devattr,
352 struct acpi_device *acpi_dev = to_acpi_device(dev);
353 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
355 mutex_lock(&resource->lock);
356 update_meter(resource);
357 mutex_unlock(&resource->lock);
359 return sprintf(buf, "%llu\n", resource->power * 1000);
363 static ssize_t show_str(struct device *dev,
364 struct device_attribute *devattr,
367 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
368 struct acpi_device *acpi_dev = to_acpi_device(dev);
369 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
372 switch (attr->index) {
374 val = resource->model_number;
377 val = resource->serial_number;
380 val = resource->oem_info;
387 return sprintf(buf, "%s\n", val);
390 static ssize_t show_val(struct device *dev,
391 struct device_attribute *devattr,
394 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
395 struct acpi_device *acpi_dev = to_acpi_device(dev);
396 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
399 switch (attr->index) {
401 val = resource->caps.min_avg_interval;
404 val = resource->caps.max_avg_interval;
407 val = resource->caps.min_cap * 1000;
410 val = resource->caps.max_cap * 1000;
413 if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
414 return sprintf(buf, "unknown\n");
416 val = resource->caps.hysteresis * 1000;
419 if (resource->caps.flags & POWER_METER_IS_BATTERY)
425 if (resource->power > resource->cap)
432 if (resource->trip[attr->index - 7] < 0)
433 return sprintf(buf, "unknown\n");
435 val = resource->trip[attr->index - 7] * 1000;
441 return sprintf(buf, "%llu\n", val);
444 static ssize_t show_accuracy(struct device *dev,
445 struct device_attribute *devattr,
448 struct acpi_device *acpi_dev = to_acpi_device(dev);
449 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
450 unsigned int acc = resource->caps.accuracy;
452 return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
455 static ssize_t show_name(struct device *dev,
456 struct device_attribute *devattr,
459 return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
462 #define RO_SENSOR_TEMPLATE(_label, _show, _index) \
469 #define RW_SENSOR_TEMPLATE(_label, _show, _set, _index) \
477 /* Sensor descriptions. If you add a sensor, update NUM_SENSORS above! */
478 static struct sensor_template meter_attrs[] = {
479 RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
480 RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
481 RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
482 RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
483 RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
484 RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
485 set_avg_interval, 0),
489 static struct sensor_template misc_cap_attrs[] = {
490 RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
491 RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
492 RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
493 RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
497 static struct sensor_template ro_cap_attrs[] = {
498 RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
502 static struct sensor_template rw_cap_attrs[] = {
503 RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
507 static struct sensor_template trip_attrs[] = {
508 RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
509 RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
513 static struct sensor_template misc_attrs[] = {
514 RO_SENSOR_TEMPLATE("name", show_name, 0),
515 RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
516 RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
517 RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
521 #undef RO_SENSOR_TEMPLATE
522 #undef RW_SENSOR_TEMPLATE
524 /* Read power domain data */
525 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
529 if (!resource->num_domain_devices)
532 for (i = 0; i < resource->num_domain_devices; i++) {
533 struct acpi_device *obj = resource->domain_devices[i];
537 sysfs_remove_link(resource->holders_dir,
538 kobject_name(&obj->dev.kobj));
539 put_device(&obj->dev);
542 kfree(resource->domain_devices);
543 kobject_put(resource->holders_dir);
544 resource->num_domain_devices = 0;
547 static int read_domain_devices(struct acpi_power_meter_resource *resource)
551 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
552 union acpi_object *pss;
555 status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
557 if (ACPI_FAILURE(status)) {
558 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
562 pss = buffer.pointer;
564 pss->type != ACPI_TYPE_PACKAGE) {
565 dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
566 "Invalid _PMD data\n");
571 if (!pss->package.count)
574 resource->domain_devices = kzalloc(sizeof(struct acpi_device *) *
575 pss->package.count, GFP_KERNEL);
576 if (!resource->domain_devices) {
581 resource->holders_dir = kobject_create_and_add("measures",
582 &resource->acpi_dev->dev.kobj);
583 if (!resource->holders_dir) {
588 resource->num_domain_devices = pss->package.count;
590 for (i = 0; i < pss->package.count; i++) {
591 struct acpi_device *obj;
592 union acpi_object *element = &(pss->package.elements[i]);
594 /* Refuse non-references */
595 if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
598 /* Create a symlink to domain objects */
599 resource->domain_devices[i] = NULL;
600 status = acpi_bus_get_device(element->reference.handle,
601 &resource->domain_devices[i]);
602 if (ACPI_FAILURE(status))
605 obj = resource->domain_devices[i];
606 get_device(&obj->dev);
608 res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
609 kobject_name(&obj->dev.kobj));
611 put_device(&obj->dev);
612 resource->domain_devices[i] = NULL;
620 kfree(resource->domain_devices);
622 kfree(buffer.pointer);
626 /* Registration and deregistration */
627 static int register_attrs(struct acpi_power_meter_resource *resource,
628 struct sensor_template *attrs)
630 struct device *dev = &resource->acpi_dev->dev;
631 struct sensor_device_attribute *sensors =
632 &resource->sensors[resource->num_sensors];
635 while (attrs->label) {
636 sensors->dev_attr.attr.name = attrs->label;
637 sensors->dev_attr.attr.mode = S_IRUGO;
638 sensors->dev_attr.show = attrs->show;
639 sensors->index = attrs->index;
642 sensors->dev_attr.attr.mode |= S_IWUSR;
643 sensors->dev_attr.store = attrs->set;
646 sysfs_attr_init(&sensors->dev_attr.attr);
647 res = device_create_file(dev, &sensors->dev_attr);
649 sensors->dev_attr.attr.name = NULL;
653 resource->num_sensors++;
661 static void remove_attrs(struct acpi_power_meter_resource *resource)
665 for (i = 0; i < resource->num_sensors; i++) {
666 if (!resource->sensors[i].dev_attr.attr.name)
668 device_remove_file(&resource->acpi_dev->dev,
669 &resource->sensors[i].dev_attr);
672 remove_domain_devices(resource);
674 resource->num_sensors = 0;
677 static int setup_attrs(struct acpi_power_meter_resource *resource)
681 res = read_domain_devices(resource);
685 if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
686 res = register_attrs(resource, meter_attrs);
691 if (resource->caps.flags & POWER_METER_CAN_CAP) {
692 if (!can_cap_in_hardware()) {
693 dev_err(&resource->acpi_dev->dev,
694 "Ignoring unsafe software power cap!\n");
695 goto skip_unsafe_cap;
698 if (resource->caps.configurable_cap)
699 res = register_attrs(resource, rw_cap_attrs);
701 res = register_attrs(resource, ro_cap_attrs);
706 res = register_attrs(resource, misc_cap_attrs);
712 if (resource->caps.flags & POWER_METER_CAN_TRIP) {
713 res = register_attrs(resource, trip_attrs);
718 res = register_attrs(resource, misc_attrs);
724 remove_attrs(resource);
728 static void free_capabilities(struct acpi_power_meter_resource *resource)
733 str = &resource->model_number;
734 for (i = 0; i < 3; i++, str++)
738 static int read_capabilities(struct acpi_power_meter_resource *resource)
742 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
743 struct acpi_buffer state = { 0, NULL };
744 struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
745 union acpi_object *pss;
749 status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
751 if (ACPI_FAILURE(status)) {
752 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC"));
756 pss = buffer.pointer;
758 pss->type != ACPI_TYPE_PACKAGE ||
759 pss->package.count != 14) {
760 dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
761 "Invalid _PMC data\n");
766 /* Grab all the integer data at once */
767 state.length = sizeof(struct acpi_power_meter_capabilities);
768 state.pointer = &resource->caps;
770 status = acpi_extract_package(pss, &format, &state);
771 if (ACPI_FAILURE(status)) {
772 ACPI_EXCEPTION((AE_INFO, status, "Invalid data"));
777 if (resource->caps.units) {
778 dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
779 "Unknown units %llu.\n",
780 resource->caps.units);
785 /* Grab the string data */
786 str = &resource->model_number;
788 for (i = 11; i < 14; i++) {
789 union acpi_object *element = &(pss->package.elements[i]);
791 if (element->type != ACPI_TYPE_STRING) {
796 *str = kzalloc(sizeof(u8) * (element->string.length + 1),
803 strncpy(*str, element->string.pointer, element->string.length);
807 dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
810 str = &resource->model_number;
811 for (i = 0; i < 3; i++, str++)
814 kfree(buffer.pointer);
818 /* Handle ACPI event notifications */
819 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
821 struct acpi_power_meter_resource *resource;
824 if (!device || !acpi_driver_data(device))
827 resource = acpi_driver_data(device);
829 mutex_lock(&resource->lock);
831 case METER_NOTIFY_CONFIG:
832 free_capabilities(resource);
833 res = read_capabilities(resource);
837 remove_attrs(resource);
838 setup_attrs(resource);
840 case METER_NOTIFY_TRIP:
841 sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
842 update_meter(resource);
844 case METER_NOTIFY_CAP:
845 sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
846 update_cap(resource);
848 case METER_NOTIFY_INTERVAL:
849 sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
850 update_avg_interval(resource);
852 case METER_NOTIFY_CAPPING:
853 sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
854 dev_info(&device->dev, "Capping in progress.\n");
859 mutex_unlock(&resource->lock);
861 acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
862 dev_name(&device->dev), event, 0);
865 static int acpi_power_meter_add(struct acpi_device *device)
868 struct acpi_power_meter_resource *resource;
873 resource = kzalloc(sizeof(struct acpi_power_meter_resource),
878 resource->sensors_valid = 0;
879 resource->acpi_dev = device;
880 mutex_init(&resource->lock);
881 strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
882 strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
883 device->driver_data = resource;
885 free_capabilities(resource);
886 res = read_capabilities(resource);
890 resource->trip[0] = resource->trip[1] = -1;
892 res = setup_attrs(resource);
896 resource->hwmon_dev = hwmon_device_register(&device->dev);
897 if (IS_ERR(resource->hwmon_dev)) {
898 res = PTR_ERR(resource->hwmon_dev);
906 remove_attrs(resource);
913 static int acpi_power_meter_remove(struct acpi_device *device, int type)
915 struct acpi_power_meter_resource *resource;
917 if (!device || !acpi_driver_data(device))
920 resource = acpi_driver_data(device);
921 hwmon_device_unregister(resource->hwmon_dev);
923 free_capabilities(resource);
924 remove_attrs(resource);
930 static int acpi_power_meter_resume(struct device *dev)
932 struct acpi_power_meter_resource *resource;
937 resource = acpi_driver_data(to_acpi_device(dev));
941 free_capabilities(resource);
942 read_capabilities(resource);
947 static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
949 static struct acpi_driver acpi_power_meter_driver = {
950 .name = "power_meter",
951 .class = ACPI_POWER_METER_CLASS,
952 .ids = power_meter_ids,
954 .add = acpi_power_meter_add,
955 .remove = acpi_power_meter_remove,
956 .notify = acpi_power_meter_notify,
958 .drv.pm = &acpi_power_meter_pm,
961 /* Module init/exit routines */
962 static int __init enable_cap_knobs(const struct dmi_system_id *d)
968 static struct dmi_system_id __initdata pm_dmi_table[] = {
970 enable_cap_knobs, "IBM Active Energy Manager",
972 DMI_MATCH(DMI_SYS_VENDOR, "IBM")
978 static int __init acpi_power_meter_init(void)
985 dmi_check_system(pm_dmi_table);
987 result = acpi_bus_register_driver(&acpi_power_meter_driver);
994 static void __exit acpi_power_meter_exit(void)
996 acpi_bus_unregister_driver(&acpi_power_meter_driver);
999 MODULE_AUTHOR("Darrick J. Wong <djwong@us.ibm.com>");
1000 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1001 MODULE_LICENSE("GPL");
1003 module_param(force_cap_on, bool, 0644);
1004 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1006 module_init(acpi_power_meter_init);
1007 module_exit(acpi_power_meter_exit);