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 ro_sensor_template {
112 ssize_t (*show)(struct device *dev,
113 struct device_attribute *devattr,
118 struct rw_sensor_template {
120 ssize_t (*show)(struct device *dev,
121 struct device_attribute *devattr,
123 ssize_t (*set)(struct device *dev,
124 struct device_attribute *devattr,
125 const char *buf, size_t count);
129 /* Averaging interval */
130 static int update_avg_interval(struct acpi_power_meter_resource *resource)
132 unsigned long long data;
135 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GAI",
137 if (ACPI_FAILURE(status)) {
138 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GAI"));
142 resource->avg_interval = data;
146 static ssize_t show_avg_interval(struct device *dev,
147 struct device_attribute *devattr,
150 struct acpi_device *acpi_dev = to_acpi_device(dev);
151 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
153 mutex_lock(&resource->lock);
154 update_avg_interval(resource);
155 mutex_unlock(&resource->lock);
157 return sprintf(buf, "%llu\n", resource->avg_interval);
160 static ssize_t set_avg_interval(struct device *dev,
161 struct device_attribute *devattr,
162 const char *buf, size_t count)
164 struct acpi_device *acpi_dev = to_acpi_device(dev);
165 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
166 union acpi_object arg0 = { ACPI_TYPE_INTEGER };
167 struct acpi_object_list args = { 1, &arg0 };
170 unsigned long long data;
173 res = kstrtoul(buf, 10, &temp);
177 if (temp > resource->caps.max_avg_interval ||
178 temp < resource->caps.min_avg_interval)
180 arg0.integer.value = temp;
182 mutex_lock(&resource->lock);
183 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PAI",
185 if (!ACPI_FAILURE(status))
186 resource->avg_interval = temp;
187 mutex_unlock(&resource->lock);
189 if (ACPI_FAILURE(status)) {
190 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PAI"));
194 /* _PAI returns 0 on success, nonzero otherwise */
202 static int update_cap(struct acpi_power_meter_resource *resource)
204 unsigned long long data;
207 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_GHL",
209 if (ACPI_FAILURE(status)) {
210 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _GHL"));
214 resource->cap = data;
218 static ssize_t show_cap(struct device *dev,
219 struct device_attribute *devattr,
222 struct acpi_device *acpi_dev = to_acpi_device(dev);
223 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
225 mutex_lock(&resource->lock);
226 update_cap(resource);
227 mutex_unlock(&resource->lock);
229 return sprintf(buf, "%llu\n", resource->cap * 1000);
232 static ssize_t set_cap(struct device *dev, struct device_attribute *devattr,
233 const char *buf, size_t count)
235 struct acpi_device *acpi_dev = to_acpi_device(dev);
236 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
237 union acpi_object arg0 = { ACPI_TYPE_INTEGER };
238 struct acpi_object_list args = { 1, &arg0 };
241 unsigned long long data;
244 res = kstrtoul(buf, 10, &temp);
249 if (temp > resource->caps.max_cap || temp < resource->caps.min_cap)
251 arg0.integer.value = temp;
253 mutex_lock(&resource->lock);
254 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_SHL",
256 if (!ACPI_FAILURE(status))
257 resource->cap = temp;
258 mutex_unlock(&resource->lock);
260 if (ACPI_FAILURE(status)) {
261 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _SHL"));
265 /* _SHL returns 0 on success, nonzero otherwise */
272 /* Power meter trip points */
273 static int set_acpi_trip(struct acpi_power_meter_resource *resource)
275 union acpi_object arg_objs[] = {
279 struct acpi_object_list args = { 2, arg_objs };
280 unsigned long long data;
283 /* Both trip levels must be set */
284 if (resource->trip[0] < 0 || resource->trip[1] < 0)
287 /* This driver stores min, max; ACPI wants max, min. */
288 arg_objs[0].integer.value = resource->trip[1];
289 arg_objs[1].integer.value = resource->trip[0];
291 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PTP",
293 if (ACPI_FAILURE(status)) {
294 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PTP"));
298 /* _PTP returns 0 on success, nonzero otherwise */
305 static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
306 const char *buf, size_t count)
308 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
309 struct acpi_device *acpi_dev = to_acpi_device(dev);
310 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
314 res = kstrtoul(buf, 10, &temp);
322 mutex_lock(&resource->lock);
323 resource->trip[attr->index - 7] = temp;
324 res = set_acpi_trip(resource);
325 mutex_unlock(&resource->lock);
334 static int update_meter(struct acpi_power_meter_resource *resource)
336 unsigned long long data;
338 unsigned long local_jiffies = jiffies;
340 if (time_before(local_jiffies, resource->sensors_last_updated +
341 msecs_to_jiffies(resource->caps.sampling_time)) &&
342 resource->sensors_valid)
345 status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
347 if (ACPI_FAILURE(status)) {
348 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMM"));
352 resource->power = data;
353 resource->sensors_valid = 1;
354 resource->sensors_last_updated = jiffies;
358 static ssize_t show_power(struct device *dev,
359 struct device_attribute *devattr,
362 struct acpi_device *acpi_dev = to_acpi_device(dev);
363 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
365 mutex_lock(&resource->lock);
366 update_meter(resource);
367 mutex_unlock(&resource->lock);
369 return sprintf(buf, "%llu\n", resource->power * 1000);
373 static ssize_t show_str(struct device *dev,
374 struct device_attribute *devattr,
377 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
378 struct acpi_device *acpi_dev = to_acpi_device(dev);
379 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
382 switch (attr->index) {
384 val = resource->model_number;
387 val = resource->serial_number;
390 val = resource->oem_info;
397 return sprintf(buf, "%s\n", val);
400 static ssize_t show_val(struct device *dev,
401 struct device_attribute *devattr,
404 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
405 struct acpi_device *acpi_dev = to_acpi_device(dev);
406 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
409 switch (attr->index) {
411 val = resource->caps.min_avg_interval;
414 val = resource->caps.max_avg_interval;
417 val = resource->caps.min_cap * 1000;
420 val = resource->caps.max_cap * 1000;
423 if (resource->caps.hysteresis == UNKNOWN_HYSTERESIS)
424 return sprintf(buf, "unknown\n");
426 val = resource->caps.hysteresis * 1000;
429 if (resource->caps.flags & POWER_METER_IS_BATTERY)
435 if (resource->power > resource->cap)
442 if (resource->trip[attr->index - 7] < 0)
443 return sprintf(buf, "unknown\n");
445 val = resource->trip[attr->index - 7] * 1000;
451 return sprintf(buf, "%llu\n", val);
454 static ssize_t show_accuracy(struct device *dev,
455 struct device_attribute *devattr,
458 struct acpi_device *acpi_dev = to_acpi_device(dev);
459 struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
460 unsigned int acc = resource->caps.accuracy;
462 return sprintf(buf, "%u.%u%%\n", acc / 1000, acc % 1000);
465 static ssize_t show_name(struct device *dev,
466 struct device_attribute *devattr,
469 return sprintf(buf, "%s\n", ACPI_POWER_METER_NAME);
472 /* Sensor descriptions. If you add a sensor, update NUM_SENSORS above! */
473 static struct ro_sensor_template meter_ro_attrs[] = {
474 {POWER_AVERAGE_NAME, show_power, 0},
475 {"power1_accuracy", show_accuracy, 0},
476 {"power1_average_interval_min", show_val, 0},
477 {"power1_average_interval_max", show_val, 1},
478 {"power1_is_battery", show_val, 5},
482 static struct rw_sensor_template meter_rw_attrs[] = {
483 {POWER_AVG_INTERVAL_NAME, show_avg_interval, set_avg_interval, 0},
484 {NULL, NULL, NULL, 0},
487 static struct ro_sensor_template misc_cap_attrs[] = {
488 {"power1_cap_min", show_val, 2},
489 {"power1_cap_max", show_val, 3},
490 {"power1_cap_hyst", show_val, 4},
491 {POWER_ALARM_NAME, show_val, 6},
495 static struct ro_sensor_template ro_cap_attrs[] = {
496 {POWER_CAP_NAME, show_cap, 0},
500 static struct rw_sensor_template rw_cap_attrs[] = {
501 {POWER_CAP_NAME, show_cap, set_cap, 0},
502 {NULL, NULL, NULL, 0},
505 static struct rw_sensor_template trip_attrs[] = {
506 {"power1_average_min", show_val, set_trip, 7},
507 {"power1_average_max", show_val, set_trip, 8},
508 {NULL, NULL, NULL, 0},
511 static struct ro_sensor_template misc_attrs[] = {
512 {"name", show_name, 0},
513 {"power1_model_number", show_str, 0},
514 {"power1_oem_info", show_str, 2},
515 {"power1_serial_number", show_str, 1},
519 /* Read power domain data */
520 static void remove_domain_devices(struct acpi_power_meter_resource *resource)
524 if (!resource->num_domain_devices)
527 for (i = 0; i < resource->num_domain_devices; i++) {
528 struct acpi_device *obj = resource->domain_devices[i];
532 sysfs_remove_link(resource->holders_dir,
533 kobject_name(&obj->dev.kobj));
534 put_device(&obj->dev);
537 kfree(resource->domain_devices);
538 kobject_put(resource->holders_dir);
539 resource->num_domain_devices = 0;
542 static int read_domain_devices(struct acpi_power_meter_resource *resource)
546 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
547 union acpi_object *pss;
550 status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
552 if (ACPI_FAILURE(status)) {
553 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
557 pss = buffer.pointer;
559 pss->type != ACPI_TYPE_PACKAGE) {
560 dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
561 "Invalid _PMD data\n");
566 if (!pss->package.count)
569 resource->domain_devices = kzalloc(sizeof(struct acpi_device *) *
570 pss->package.count, GFP_KERNEL);
571 if (!resource->domain_devices) {
576 resource->holders_dir = kobject_create_and_add("measures",
577 &resource->acpi_dev->dev.kobj);
578 if (!resource->holders_dir) {
583 resource->num_domain_devices = pss->package.count;
585 for (i = 0; i < pss->package.count; i++) {
586 struct acpi_device *obj;
587 union acpi_object *element = &(pss->package.elements[i]);
589 /* Refuse non-references */
590 if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
593 /* Create a symlink to domain objects */
594 resource->domain_devices[i] = NULL;
595 status = acpi_bus_get_device(element->reference.handle,
596 &resource->domain_devices[i]);
597 if (ACPI_FAILURE(status))
600 obj = resource->domain_devices[i];
601 get_device(&obj->dev);
603 res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
604 kobject_name(&obj->dev.kobj));
606 put_device(&obj->dev);
607 resource->domain_devices[i] = NULL;
615 kfree(resource->domain_devices);
617 kfree(buffer.pointer);
621 /* Registration and deregistration */
622 static int register_ro_attrs(struct acpi_power_meter_resource *resource,
623 struct ro_sensor_template *ro)
625 struct device *dev = &resource->acpi_dev->dev;
626 struct sensor_device_attribute *sensors =
627 &resource->sensors[resource->num_sensors];
631 sensors->dev_attr.attr.name = ro->label;
632 sensors->dev_attr.attr.mode = S_IRUGO;
633 sensors->dev_attr.show = ro->show;
634 sensors->index = ro->index;
636 sysfs_attr_init(&sensors->dev_attr.attr);
637 res = device_create_file(dev, &sensors->dev_attr);
639 sensors->dev_attr.attr.name = NULL;
643 resource->num_sensors++;
651 static int register_rw_attrs(struct acpi_power_meter_resource *resource,
652 struct rw_sensor_template *rw)
654 struct device *dev = &resource->acpi_dev->dev;
655 struct sensor_device_attribute *sensors =
656 &resource->sensors[resource->num_sensors];
660 sensors->dev_attr.attr.name = rw->label;
661 sensors->dev_attr.attr.mode = S_IRUGO | S_IWUSR;
662 sensors->dev_attr.show = rw->show;
663 sensors->dev_attr.store = rw->set;
664 sensors->index = rw->index;
666 sysfs_attr_init(&sensors->dev_attr.attr);
667 res = device_create_file(dev, &sensors->dev_attr);
669 sensors->dev_attr.attr.name = NULL;
673 resource->num_sensors++;
681 static void remove_attrs(struct acpi_power_meter_resource *resource)
685 for (i = 0; i < resource->num_sensors; i++) {
686 if (!resource->sensors[i].dev_attr.attr.name)
688 device_remove_file(&resource->acpi_dev->dev,
689 &resource->sensors[i].dev_attr);
692 remove_domain_devices(resource);
694 resource->num_sensors = 0;
697 static int setup_attrs(struct acpi_power_meter_resource *resource)
701 res = read_domain_devices(resource);
705 if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
706 res = register_ro_attrs(resource, meter_ro_attrs);
709 res = register_rw_attrs(resource, meter_rw_attrs);
714 if (resource->caps.flags & POWER_METER_CAN_CAP) {
715 if (!can_cap_in_hardware()) {
716 dev_err(&resource->acpi_dev->dev,
717 "Ignoring unsafe software power cap!\n");
718 goto skip_unsafe_cap;
721 if (resource->caps.configurable_cap) {
722 res = register_rw_attrs(resource, rw_cap_attrs);
726 res = register_ro_attrs(resource, ro_cap_attrs);
730 res = register_ro_attrs(resource, misc_cap_attrs);
736 if (resource->caps.flags & POWER_METER_CAN_TRIP) {
737 res = register_rw_attrs(resource, trip_attrs);
742 res = register_ro_attrs(resource, misc_attrs);
748 remove_attrs(resource);
752 static void free_capabilities(struct acpi_power_meter_resource *resource)
757 str = &resource->model_number;
758 for (i = 0; i < 3; i++, str++)
762 static int read_capabilities(struct acpi_power_meter_resource *resource)
766 struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
767 struct acpi_buffer state = { 0, NULL };
768 struct acpi_buffer format = { sizeof("NNNNNNNNNNN"), "NNNNNNNNNNN" };
769 union acpi_object *pss;
773 status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMC", NULL,
775 if (ACPI_FAILURE(status)) {
776 ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMC"));
780 pss = buffer.pointer;
782 pss->type != ACPI_TYPE_PACKAGE ||
783 pss->package.count != 14) {
784 dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
785 "Invalid _PMC data\n");
790 /* Grab all the integer data at once */
791 state.length = sizeof(struct acpi_power_meter_capabilities);
792 state.pointer = &resource->caps;
794 status = acpi_extract_package(pss, &format, &state);
795 if (ACPI_FAILURE(status)) {
796 ACPI_EXCEPTION((AE_INFO, status, "Invalid data"));
801 if (resource->caps.units) {
802 dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
803 "Unknown units %llu.\n",
804 resource->caps.units);
809 /* Grab the string data */
810 str = &resource->model_number;
812 for (i = 11; i < 14; i++) {
813 union acpi_object *element = &(pss->package.elements[i]);
815 if (element->type != ACPI_TYPE_STRING) {
820 *str = kzalloc(sizeof(u8) * (element->string.length + 1),
827 strncpy(*str, element->string.pointer, element->string.length);
831 dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
834 str = &resource->model_number;
835 for (i = 0; i < 3; i++, str++)
838 kfree(buffer.pointer);
842 /* Handle ACPI event notifications */
843 static void acpi_power_meter_notify(struct acpi_device *device, u32 event)
845 struct acpi_power_meter_resource *resource;
848 if (!device || !acpi_driver_data(device))
851 resource = acpi_driver_data(device);
853 mutex_lock(&resource->lock);
855 case METER_NOTIFY_CONFIG:
856 free_capabilities(resource);
857 res = read_capabilities(resource);
861 remove_attrs(resource);
862 setup_attrs(resource);
864 case METER_NOTIFY_TRIP:
865 sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
866 update_meter(resource);
868 case METER_NOTIFY_CAP:
869 sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
870 update_cap(resource);
872 case METER_NOTIFY_INTERVAL:
873 sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
874 update_avg_interval(resource);
876 case METER_NOTIFY_CAPPING:
877 sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
878 dev_info(&device->dev, "Capping in progress.\n");
883 mutex_unlock(&resource->lock);
885 acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
886 dev_name(&device->dev), event, 0);
889 static int acpi_power_meter_add(struct acpi_device *device)
892 struct acpi_power_meter_resource *resource;
897 resource = kzalloc(sizeof(struct acpi_power_meter_resource),
902 resource->sensors_valid = 0;
903 resource->acpi_dev = device;
904 mutex_init(&resource->lock);
905 strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
906 strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS);
907 device->driver_data = resource;
909 free_capabilities(resource);
910 res = read_capabilities(resource);
914 resource->trip[0] = resource->trip[1] = -1;
916 res = setup_attrs(resource);
920 resource->hwmon_dev = hwmon_device_register(&device->dev);
921 if (IS_ERR(resource->hwmon_dev)) {
922 res = PTR_ERR(resource->hwmon_dev);
930 remove_attrs(resource);
937 static int acpi_power_meter_remove(struct acpi_device *device, int type)
939 struct acpi_power_meter_resource *resource;
941 if (!device || !acpi_driver_data(device))
944 resource = acpi_driver_data(device);
945 hwmon_device_unregister(resource->hwmon_dev);
947 free_capabilities(resource);
948 remove_attrs(resource);
954 static int acpi_power_meter_resume(struct acpi_device *device)
956 struct acpi_power_meter_resource *resource;
958 if (!device || !acpi_driver_data(device))
961 resource = acpi_driver_data(device);
962 free_capabilities(resource);
963 read_capabilities(resource);
968 static struct acpi_driver acpi_power_meter_driver = {
969 .name = "power_meter",
970 .class = ACPI_POWER_METER_CLASS,
971 .ids = power_meter_ids,
973 .add = acpi_power_meter_add,
974 .remove = acpi_power_meter_remove,
975 .resume = acpi_power_meter_resume,
976 .notify = acpi_power_meter_notify,
980 /* Module init/exit routines */
981 static int __init enable_cap_knobs(const struct dmi_system_id *d)
987 static struct dmi_system_id __initdata pm_dmi_table[] = {
989 enable_cap_knobs, "IBM Active Energy Manager",
991 DMI_MATCH(DMI_SYS_VENDOR, "IBM")
997 static int __init acpi_power_meter_init(void)
1004 dmi_check_system(pm_dmi_table);
1006 result = acpi_bus_register_driver(&acpi_power_meter_driver);
1013 static void __exit acpi_power_meter_exit(void)
1015 acpi_bus_unregister_driver(&acpi_power_meter_driver);
1018 MODULE_AUTHOR("Darrick J. Wong <djwong@us.ibm.com>");
1019 MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
1020 MODULE_LICENSE("GPL");
1022 module_param(force_cap_on, bool, 0644);
1023 MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
1025 module_init(acpi_power_meter_init);
1026 module_exit(acpi_power_meter_exit);