Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / hwmon / acpi_power_meter.c
diff --git a/kernel/drivers/hwmon/acpi_power_meter.c b/kernel/drivers/hwmon/acpi_power_meter.c
new file mode 100644 (file)
index 0000000..579bdf9
--- /dev/null
@@ -0,0 +1,1015 @@
+/*
+ * A hwmon driver for ACPI 4.0 power meters
+ * Copyright (C) 2009 IBM
+ *
+ * Author: Darrick J. Wong <darrick.wong@oracle.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/dmi.h>
+#include <linux/slab.h>
+#include <linux/kdev_t.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/err.h>
+#include <linux/acpi.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         "pwr_meter_resource"
+
+#define NUM_SENSORS                    17
+
+#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
+
+#define POWER_AVERAGE_NAME     "power1_average"
+#define POWER_CAP_NAME         "power1_cap"
+#define POWER_AVG_INTERVAL_NAME        "power1_average_interval"
+#define POWER_ALARM_NAME       "power1_alarm"
+
+static int cap_in_hardware;
+static bool force_cap_on;
+
+static int can_cap_in_hardware(void)
+{
+       return force_cap_on || cap_in_hardware;
+}
+
+static const struct acpi_device_id power_meter_ids[] = {
+       {"ACPI000D", 0},
+       {"", 0},
+};
+MODULE_DEVICE_TABLE(acpi, power_meter_ids);
+
+struct acpi_power_meter_capabilities {
+       u64             flags;
+       u64             units;
+       u64             type;
+       u64             accuracy;
+       u64             sampling_time;
+       u64             min_avg_interval;
+       u64             max_avg_interval;
+       u64             hysteresis;
+       u64             configurable_cap;
+       u64             min_cap;
+       u64             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_string             model_number;
+       acpi_string             serial_number;
+       acpi_string             oem_info;
+       u64             power;
+       u64             cap;
+       u64             avg_interval;
+       int                     sensors_valid;
+       unsigned long           sensors_last_updated;
+       struct sensor_device_attribute  sensors[NUM_SENSORS];
+       int                     num_sensors;
+       s64                     trip[2];
+       int                     num_domain_devices;
+       struct acpi_device      **domain_devices;
+       struct kobject          *holders_dir;
+};
+
+struct 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 = kstrtoul(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;
+       }
+
+       /* _PAI returns 0 on success, nonzero otherwise */
+       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 = kstrtoul(buf, 10, &temp);
+       if (res)
+               return res;
+
+       temp = DIV_ROUND_CLOSEST(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;
+       }
+
+       /* _SHL returns 0 on success, nonzero otherwise */
+       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;
+       }
+
+       /* _PTP returns 0 on success, nonzero otherwise */
+       if (data)
+               return -EINVAL;
+
+       return 0;
+}
+
+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 = kstrtoul(buf, 10, &temp);
+       if (res)
+               return res;
+
+       temp = DIV_ROUND_CLOSEST(temp, 1000);
+
+       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_str(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_string val;
+
+       switch (attr->index) {
+       case 0:
+               val = resource->model_number;
+               break;
+       case 1:
+               val = resource->serial_number;
+               break;
+       case 2:
+               val = resource->oem_info;
+               break;
+       default:
+               WARN(1, "Implementation error: unexpected attribute index %d\n",
+                    attr->index);
+               val = "";
+               break;
+       }
+
+       return sprintf(buf, "%s\n", val);
+}
+
+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;
+       u64 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:
+               WARN(1, "Implementation error: unexpected attribute index %d\n",
+                    attr->index);
+               break;
+       }
+
+       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);
+}
+
+#define RO_SENSOR_TEMPLATE(_label, _show, _index)      \
+       {                                               \
+               .label = _label,                        \
+               .show  = _show,                         \
+               .index = _index,                        \
+       }
+
+#define RW_SENSOR_TEMPLATE(_label, _show, _set, _index)        \
+       {                                               \
+               .label = _label,                        \
+               .show  = _show,                         \
+               .set   = _set,                          \
+               .index = _index,                        \
+       }
+
+/* Sensor descriptions.  If you add a sensor, update NUM_SENSORS above! */
+static struct sensor_template meter_attrs[] = {
+       RO_SENSOR_TEMPLATE(POWER_AVERAGE_NAME, show_power, 0),
+       RO_SENSOR_TEMPLATE("power1_accuracy", show_accuracy, 0),
+       RO_SENSOR_TEMPLATE("power1_average_interval_min", show_val, 0),
+       RO_SENSOR_TEMPLATE("power1_average_interval_max", show_val, 1),
+       RO_SENSOR_TEMPLATE("power1_is_battery", show_val, 5),
+       RW_SENSOR_TEMPLATE(POWER_AVG_INTERVAL_NAME, show_avg_interval,
+               set_avg_interval, 0),
+       {},
+};
+
+static struct sensor_template misc_cap_attrs[] = {
+       RO_SENSOR_TEMPLATE("power1_cap_min", show_val, 2),
+       RO_SENSOR_TEMPLATE("power1_cap_max", show_val, 3),
+       RO_SENSOR_TEMPLATE("power1_cap_hyst", show_val, 4),
+       RO_SENSOR_TEMPLATE(POWER_ALARM_NAME, show_val, 6),
+       {},
+};
+
+static struct sensor_template ro_cap_attrs[] = {
+       RO_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, 0),
+       {},
+};
+
+static struct sensor_template rw_cap_attrs[] = {
+       RW_SENSOR_TEMPLATE(POWER_CAP_NAME, show_cap, set_cap, 0),
+       {},
+};
+
+static struct sensor_template trip_attrs[] = {
+       RW_SENSOR_TEMPLATE("power1_average_min", show_val, set_trip, 7),
+       RW_SENSOR_TEMPLATE("power1_average_max", show_val, set_trip, 8),
+       {},
+};
+
+static struct sensor_template misc_attrs[] = {
+       RO_SENSOR_TEMPLATE("name", show_name, 0),
+       RO_SENSOR_TEMPLATE("power1_model_number", show_str, 0),
+       RO_SENSOR_TEMPLATE("power1_oem_info", show_str, 2),
+       RO_SENSOR_TEMPLATE("power1_serial_number", show_str, 1),
+       {},
+};
+
+#undef RO_SENSOR_TEMPLATE
+#undef RW_SENSOR_TEMPLATE
+
+/* Read power domain data */
+static void remove_domain_devices(struct acpi_power_meter_resource *resource)
+{
+       int i;
+
+       if (!resource->num_domain_devices)
+               return;
+
+       for (i = 0; i < resource->num_domain_devices; i++) {
+               struct acpi_device *obj = resource->domain_devices[i];
+               if (!obj)
+                       continue;
+
+               sysfs_remove_link(resource->holders_dir,
+                                 kobject_name(&obj->dev.kobj));
+               put_device(&obj->dev);
+       }
+
+       kfree(resource->domain_devices);
+       kobject_put(resource->holders_dir);
+       resource->num_domain_devices = 0;
+}
+
+static int read_domain_devices(struct acpi_power_meter_resource *resource)
+{
+       int res = 0;
+       int i;
+       struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+       union acpi_object *pss;
+       acpi_status status;
+
+       status = acpi_evaluate_object(resource->acpi_dev->handle, "_PMD", NULL,
+                                     &buffer);
+       if (ACPI_FAILURE(status)) {
+               ACPI_EXCEPTION((AE_INFO, status, "Evaluating _PMD"));
+               return -ENODEV;
+       }
+
+       pss = buffer.pointer;
+       if (!pss ||
+           pss->type != ACPI_TYPE_PACKAGE) {
+               dev_err(&resource->acpi_dev->dev, ACPI_POWER_METER_NAME
+                       "Invalid _PMD data\n");
+               res = -EFAULT;
+               goto end;
+       }
+
+       if (!pss->package.count)
+               goto end;
+
+       resource->domain_devices = kzalloc(sizeof(struct acpi_device *) *
+                                          pss->package.count, GFP_KERNEL);
+       if (!resource->domain_devices) {
+               res = -ENOMEM;
+               goto end;
+       }
+
+       resource->holders_dir = kobject_create_and_add("measures",
+                                       &resource->acpi_dev->dev.kobj);
+       if (!resource->holders_dir) {
+               res = -ENOMEM;
+               goto exit_free;
+       }
+
+       resource->num_domain_devices = pss->package.count;
+
+       for (i = 0; i < pss->package.count; i++) {
+               struct acpi_device *obj;
+               union acpi_object *element = &(pss->package.elements[i]);
+
+               /* Refuse non-references */
+               if (element->type != ACPI_TYPE_LOCAL_REFERENCE)
+                       continue;
+
+               /* Create a symlink to domain objects */
+               resource->domain_devices[i] = NULL;
+               if (acpi_bus_get_device(element->reference.handle,
+                                       &resource->domain_devices[i]))
+                       continue;
+
+               obj = resource->domain_devices[i];
+               get_device(&obj->dev);
+
+               res = sysfs_create_link(resource->holders_dir, &obj->dev.kobj,
+                                     kobject_name(&obj->dev.kobj));
+               if (res) {
+                       put_device(&obj->dev);
+                       resource->domain_devices[i] = NULL;
+               }
+       }
+
+       res = 0;
+       goto end;
+
+exit_free:
+       kfree(resource->domain_devices);
+end:
+       kfree(buffer.pointer);
+       return res;
+}
+
+/* Registration and deregistration */
+static int register_attrs(struct acpi_power_meter_resource *resource,
+                         struct sensor_template *attrs)
+{
+       struct device *dev = &resource->acpi_dev->dev;
+       struct sensor_device_attribute *sensors =
+               &resource->sensors[resource->num_sensors];
+       int res = 0;
+
+       while (attrs->label) {
+               sensors->dev_attr.attr.name = attrs->label;
+               sensors->dev_attr.attr.mode = S_IRUGO;
+               sensors->dev_attr.show = attrs->show;
+               sensors->index = attrs->index;
+
+               if (attrs->set) {
+                       sensors->dev_attr.attr.mode |= S_IWUSR;
+                       sensors->dev_attr.store = attrs->set;
+               }
+
+               sysfs_attr_init(&sensors->dev_attr.attr);
+               res = device_create_file(dev, &sensors->dev_attr);
+               if (res) {
+                       sensors->dev_attr.attr.name = NULL;
+                       goto error;
+               }
+               sensors++;
+               resource->num_sensors++;
+               attrs++;
+       }
+
+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);
+       }
+
+       remove_domain_devices(resource);
+
+       resource->num_sensors = 0;
+}
+
+static int setup_attrs(struct acpi_power_meter_resource *resource)
+{
+       int res = 0;
+
+       res = read_domain_devices(resource);
+       if (res)
+               return res;
+
+       if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
+               res = register_attrs(resource, meter_attrs);
+               if (res)
+                       goto error;
+       }
+
+       if (resource->caps.flags & POWER_METER_CAN_CAP) {
+               if (!can_cap_in_hardware()) {
+                       dev_err(&resource->acpi_dev->dev,
+                               "Ignoring unsafe software power cap!\n");
+                       goto skip_unsafe_cap;
+               }
+
+               if (resource->caps.configurable_cap)
+                       res = register_attrs(resource, rw_cap_attrs);
+               else
+                       res = register_attrs(resource, ro_cap_attrs);
+
+               if (res)
+                       goto error;
+
+               res = register_attrs(resource, misc_cap_attrs);
+               if (res)
+                       goto error;
+       }
+
+skip_unsafe_cap:
+       if (resource->caps.flags & POWER_METER_CAN_TRIP) {
+               res = register_attrs(resource, trip_attrs);
+               if (res)
+                       goto error;
+       }
+
+       res = register_attrs(resource, misc_attrs);
+       if (res)
+               goto error;
+
+       return res;
+error:
+       remove_attrs(resource);
+       return res;
+}
+
+static void free_capabilities(struct acpi_power_meter_resource *resource)
+{
+       acpi_string *str;
+       int i;
+
+       str = &resource->model_number;
+       for (i = 0; i < 3; i++, str++)
+               kfree(*str);
+}
+
+static int read_capabilities(struct acpi_power_meter_resource *resource)
+{
+       int res = 0;
+       int i;
+       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_string *str;
+       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, ACPI_POWER_METER_NAME
+                       "Invalid _PMC data\n");
+               res = -EFAULT;
+               goto end;
+       }
+
+       /* Grab all the integer data at once */
+       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, ACPI_POWER_METER_NAME
+                       "Unknown units %llu.\n",
+                       resource->caps.units);
+               res = -EINVAL;
+               goto end;
+       }
+
+       /* Grab the string data */
+       str = &resource->model_number;
+
+       for (i = 11; i < 14; i++) {
+               union acpi_object *element = &(pss->package.elements[i]);
+
+               if (element->type != ACPI_TYPE_STRING) {
+                       res = -EINVAL;
+                       goto error;
+               }
+
+               *str = kzalloc(sizeof(u8) * (element->string.length + 1),
+                              GFP_KERNEL);
+               if (!*str) {
+                       res = -ENOMEM;
+                       goto error;
+               }
+
+               strncpy(*str, element->string.pointer, element->string.length);
+               str++;
+       }
+
+       dev_info(&resource->acpi_dev->dev, "Found ACPI power meter.\n");
+       goto end;
+error:
+       str = &resource->model_number;
+       for (i = 0; i < 3; i++, str++)
+               kfree(*str);
+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:
+               free_capabilities(resource);
+               res = read_capabilities(resource);
+               if (res)
+                       break;
+
+               remove_attrs(resource);
+               setup_attrs(resource);
+               break;
+       case METER_NOTIFY_TRIP:
+               sysfs_notify(&device->dev.kobj, NULL, POWER_AVERAGE_NAME);
+               update_meter(resource);
+               break;
+       case METER_NOTIFY_CAP:
+               sysfs_notify(&device->dev.kobj, NULL, POWER_CAP_NAME);
+               update_cap(resource);
+               break;
+       case METER_NOTIFY_INTERVAL:
+               sysfs_notify(&device->dev.kobj, NULL, POWER_AVG_INTERVAL_NAME);
+               update_avg_interval(resource);
+               break;
+       case METER_NOTIFY_CAPPING:
+               sysfs_notify(&device->dev.kobj, NULL, POWER_ALARM_NAME);
+               dev_info(&device->dev, "Capping in progress.\n");
+               break;
+       default:
+               WARN(1, "Unexpected event %d\n", event);
+               break;
+       }
+       mutex_unlock(&resource->lock);
+
+       acpi_bus_generate_netlink_event(ACPI_POWER_METER_CLASS,
+                                       dev_name(&device->dev), event, 0);
+}
+
+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;
+
+       free_capabilities(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)
+{
+       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);
+
+       free_capabilities(resource);
+       remove_attrs(resource);
+
+       kfree(resource);
+       return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+
+static int acpi_power_meter_resume(struct device *dev)
+{
+       struct acpi_power_meter_resource *resource;
+
+       if (!dev)
+               return -EINVAL;
+
+       resource = acpi_driver_data(to_acpi_device(dev));
+       if (!resource)
+               return -EINVAL;
+
+       free_capabilities(resource);
+       read_capabilities(resource);
+
+       return 0;
+}
+
+#endif /* CONFIG_PM_SLEEP */
+
+static SIMPLE_DEV_PM_OPS(acpi_power_meter_pm, NULL, acpi_power_meter_resume);
+
+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,
+               .notify = acpi_power_meter_notify,
+               },
+       .drv.pm = &acpi_power_meter_pm,
+};
+
+/* Module init/exit routines */
+static int __init enable_cap_knobs(const struct dmi_system_id *d)
+{
+       cap_in_hardware = 1;
+       return 0;
+}
+
+static struct dmi_system_id __initdata pm_dmi_table[] = {
+       {
+               enable_cap_knobs, "IBM Active Energy Manager",
+               {
+                       DMI_MATCH(DMI_SYS_VENDOR, "IBM")
+               },
+       },
+       {}
+};
+
+static int __init acpi_power_meter_init(void)
+{
+       int result;
+
+       if (acpi_disabled)
+               return -ENODEV;
+
+       dmi_check_system(pm_dmi_table);
+
+       result = acpi_bus_register_driver(&acpi_power_meter_driver);
+       if (result < 0)
+               return result;
+
+       return 0;
+}
+
+static void __exit acpi_power_meter_exit(void)
+{
+       acpi_bus_unregister_driver(&acpi_power_meter_driver);
+}
+
+MODULE_AUTHOR("Darrick J. Wong <darrick.wong@oracle.com>");
+MODULE_DESCRIPTION("ACPI 4.0 power meter driver");
+MODULE_LICENSE("GPL");
+
+module_param(force_cap_on, bool, 0644);
+MODULE_PARM_DESC(force_cap_on, "Enable power cap even it is unsafe to do so.");
+
+module_init(acpi_power_meter_init);
+module_exit(acpi_power_meter_exit);