diff mbox

[2/2] acpi_power_meter: hwmon driver for ACPI 4.0 power meters

Message ID 20090725004335.20709.52288.stgit@elm3a70.beaverton.ibm.com (mailing list archive)
State RFC, archived
Headers show

Commit Message

Darrick J. Wong July 25, 2009, 12:43 a.m. UTC
This driver exposes ACPI 4.0 compliant power meters as hardware monitoring
devices.

Signed-off-by: Darrick J. Wong <djwong@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



--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

Zhao, Yakui July 27, 2009, 1:44 a.m. UTC | #1
On Sat, 2009-07-25 at 08:43 +0800, Darrick J. Wong wrote:
> This driver exposes ACPI 4.0 compliant power meters as hardware monitoring
> devices.
It seems OK to me. But it seems that some attributes can't be obtained
by using the hwmon sys I/F.
   a. Can we add a sys I/F that can exports the Power meter capability?
display all the content of _PMC as what we have done in battery
   b. Add a sys I/F that displays the name of device list measured by
the power meter if there exists the _PMD object.

Thanks.

> 
> Signed-off-by: Darrick J. Wong <djwong@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@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@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);
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Zhang, Rui July 27, 2009, 6:45 a.m. UTC | #2
Hi, Darrick,

great job. :)
comments in-line.

On Sat, 2009-07-25 at 08:43 +0800, Darrick J. Wong wrote:
> +/* 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);
> +}

we should at least send a netlink event for an ACPI power meter
notification, shouldn't we?

> +
> +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;
> +       }
> +

we should create the hwmon sysfs I/F for the hwmon device,
i.e. add the hwmon attributes
under /sys/devices/LINUXSYS:00/.../ACPI000D:00/hwmon0/
rather than /sys/devices/LINUXSYS:00/.../ACPI000D:00/

> +       res = 0;
> +       goto exit;
> +
> +exit_remove:
> +       remove_attrs(resource);
> +exit_free:
> +       kfree(resource);
> +exit:
> +       return res;
> +}
> +
> +
> +static int __init acpi_power_meter_init(void)
> +{
> +       int result;
> +
	  if (acpi_disable)
		return -ENODEV;

> +       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@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);
> 
plus, _PMD is not supported in this driver, right?
I agree with Yakui that we can create some ACPI device sysfs attributes
besides the hwmon ones. e.g. exporting devices measured by the current
ACPI power meter device to user space.

thanks,
rui

--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Len Brown July 28, 2009, 1:25 a.m. UTC | #3
Hi Darrick,
On the system you are planning to run this on...
Are the power meters in the processor, or elsewhere?

If they are the ones in the processor, I'd rather that
Linux use a native model-specific driver to access those
registers and not use ACPI.

thanks,
Len Brown, Intel Open Source Technology Center
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Darrick J. Wong Aug. 3, 2009, 8:48 p.m. UTC | #4
On Mon, Jul 27, 2009 at 09:44:27AM +0800, ykzhao wrote:
> On Sat, 2009-07-25 at 08:43 +0800, Darrick J. Wong wrote:
> > This driver exposes ACPI 4.0 compliant power meters as hardware monitoring
> > devices.
> It seems OK to me. But it seems that some attributes can't be obtained
> by using the hwmon sys I/F.
>    a. Can we add a sys I/F that can exports the Power meter capability?
> display all the content of _PMC as what we have done in battery

Are you talking about all 17 fields of the _PMC return value?  Or specifically
the feature bit field "Supported Capabilities"?  The feature bits control
whether or not the corresponding sysfs attributes even show up, and the other
fields (except the string data) are all there.  I suppose it would be useful to
display the OEM data too...

>    b. Add a sys I/F that displays the name of device list measured by
> the power meter if there exists the _PMD object.

As soon as I figure out how to do that. :)

Sorry for the slow response as I was mountain climbing = no Internet.

--D
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Darrick J. Wong Aug. 3, 2009, 8:52 p.m. UTC | #5
On Mon, Jul 27, 2009 at 02:45:55PM +0800, Zhang Rui wrote:
> Hi, Darrick,
> 
> great job. :)

Thanks.

> we should at least send a netlink event for an ACPI power meter
> notification, shouldn't we?

Yes, an event would be useful at the very least for when the system starts
capping, though unfortunately there doesn't seem to be a Notify event for when
capping ends.

> we should create the hwmon sysfs I/F for the hwmon device,
> i.e. add the hwmon attributes
> under /sys/devices/LINUXSYS:00/.../ACPI000D:00/hwmon0/
> rather than /sys/devices/LINUXSYS:00/.../ACPI000D:00/

Hee, this is a tricky matter.  The other hwmon drivers create sysfs attributes
under the sysfs object, not in a separate "hwmonX" object, and as I recall
libsensors reads symlinks under the device object to figure out which bus the
sensor device lives on.  If it can't figure that out, it ignores the hwmon
device.

> 	  if (acpi_disable)
> 		return -ENODEV;

Noted.

> plus, _PMD is not supported in this driver, right?
> I agree with Yakui that we can create some ACPI device sysfs attributes
> besides the hwmon ones. e.g. exporting devices measured by the current
> ACPI power meter device to user space.

I agree.

--D
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Darrick J. Wong Aug. 3, 2009, 8:58 p.m. UTC | #6
On Mon, Jul 27, 2009 at 09:25:54PM -0400, Len Brown wrote:
> Hi Darrick,
> On the system you are planning to run this on...
> Are the power meters in the processor, or elsewhere?
> 
> If they are the ones in the processor, I'd rather that
> Linux use a native model-specific driver to access those
> registers and not use ACPI.

They're not in the processor.  Right now we're simulating the meters in kvm
until we get real hardware, though it could be a mechanism to report per-VM
power use.

--D
--
To unsubscribe from this list: send the line "unsubscribe linux-acpi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

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@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@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);