提交 38bb0849 编写于 作者: F Frans Pop 提交者: Len Brown

thermal: sysfs-api.txt - reformat for improved readability

The document currently uses large indentations which make the text
too wide for easy readability. Also improve general consistency.
Signed-off-by: NFrans Pop <elendil@planet.nl>
Acked-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLen Brown <len.brown@intel.com>
上级 625120a4
Generic Thermal Sysfs driver How To Generic Thermal Sysfs driver How To
========================= ===================================
Written by Sujith Thomas <sujith.thomas@intel.com>, Zhang Rui <rui.zhang@intel.com> Written by Sujith Thomas <sujith.thomas@intel.com>, Zhang Rui <rui.zhang@intel.com>
...@@ -10,20 +10,20 @@ Copyright (c) 2008 Intel Corporation ...@@ -10,20 +10,20 @@ Copyright (c) 2008 Intel Corporation
0. Introduction 0. Introduction
The generic thermal sysfs provides a set of interfaces for thermal zone devices (sensors) The generic thermal sysfs provides a set of interfaces for thermal zone
and thermal cooling devices (fan, processor...) to register with the thermal management devices (sensors) and thermal cooling devices (fan, processor...) to register
solution and to be a part of it. with the thermal management solution and to be a part of it.
This how-to focuses on enabling new thermal zone and cooling devices to participate This how-to focuses on enabling new thermal zone and cooling devices to
in thermal management. participate in thermal management.
This solution is platform independent and any type of thermal zone devices and This solution is platform independent and any type of thermal zone devices
cooling devices should be able to make use of the infrastructure. and cooling devices should be able to make use of the infrastructure.
The main task of the thermal sysfs driver is to expose thermal zone attributes as well The main task of the thermal sysfs driver is to expose thermal zone attributes
as cooling device attributes to the user space. as well as cooling device attributes to the user space.
An intelligent thermal management application can make decisions based on inputs An intelligent thermal management application can make decisions based on
from thermal zone attributes (the current temperature and trip point temperature) inputs from thermal zone attributes (the current temperature and trip point
and throttle appropriate devices. temperature) and throttle appropriate devices.
[0-*] denotes any positive number starting from 0 [0-*] denotes any positive number starting from 0
[1-*] denotes any positive number starting from 1 [1-*] denotes any positive number starting from 1
...@@ -31,77 +31,77 @@ and throttle appropriate devices. ...@@ -31,77 +31,77 @@ and throttle appropriate devices.
1. thermal sysfs driver interface functions 1. thermal sysfs driver interface functions
1.1 thermal zone device interface 1.1 thermal zone device interface
1.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name, int trips, 1.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name,
void *devdata, struct thermal_zone_device_ops *ops) int trips, void *devdata, struct thermal_zone_device_ops *ops)
This interface function adds a new thermal zone device (sensor) to This interface function adds a new thermal zone device (sensor) to
/sys/class/thermal folder as thermal_zone[0-*]. /sys/class/thermal folder as thermal_zone[0-*]. It tries to bind all the
It tries to bind all the thermal cooling devices registered at the same time. thermal cooling devices registered at the same time.
name: the thermal zone name. name: the thermal zone name.
trips: the total number of trip points this thermal zone supports. trips: the total number of trip points this thermal zone supports.
devdata: device private data devdata: device private data
ops: thermal zone device call-backs. ops: thermal zone device call-backs.
.bind: bind the thermal zone device with a thermal cooling device. .bind: bind the thermal zone device with a thermal cooling device.
.unbind: unbind the thermal zone device with a thermal cooling device. .unbind: unbind the thermal zone device with a thermal cooling device.
.get_temp: get the current temperature of the thermal zone. .get_temp: get the current temperature of the thermal zone.
.get_mode: get the current mode (user/kernel) of the thermal zone. .get_mode: get the current mode (user/kernel) of the thermal zone.
"kernel" means thermal management is done in kernel. - "kernel" means thermal management is done in kernel.
"user" will prevent kernel thermal driver actions upon trip points - "user" will prevent kernel thermal driver actions upon trip points
so that user applications can take charge of thermal management. so that user applications can take charge of thermal management.
.set_mode: set the mode (user/kernel) of the thermal zone. .set_mode: set the mode (user/kernel) of the thermal zone.
.get_trip_type: get the type of certain trip point. .get_trip_type: get the type of certain trip point.
.get_trip_temp: get the temperature above which the certain trip point .get_trip_temp: get the temperature above which the certain trip point
will be fired. will be fired.
1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz) 1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz)
This interface function removes the thermal zone device. This interface function removes the thermal zone device.
It deletes the corresponding entry form /sys/class/thermal folder and unbind all It deletes the corresponding entry form /sys/class/thermal folder and
the thermal cooling devices it uses. unbind all the thermal cooling devices it uses.
1.2 thermal cooling device interface 1.2 thermal cooling device interface
1.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char *name, 1.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char *name,
void *devdata, struct thermal_cooling_device_ops *) void *devdata, struct thermal_cooling_device_ops *)
This interface function adds a new thermal cooling device (fan/processor/...) to This interface function adds a new thermal cooling device (fan/processor/...)
/sys/class/thermal/ folder as cooling_device[0-*]. to /sys/class/thermal/ folder as cooling_device[0-*]. It tries to bind itself
It tries to bind itself to all the thermal zone devices register at the same time. to all the thermal zone devices register at the same time.
name: the cooling device name. name: the cooling device name.
devdata: device private data. devdata: device private data.
ops: thermal cooling devices call-backs. ops: thermal cooling devices call-backs.
.get_max_state: get the Maximum throttle state of the cooling device. .get_max_state: get the Maximum throttle state of the cooling device.
.get_cur_state: get the Current throttle state of the cooling device. .get_cur_state: get the Current throttle state of the cooling device.
.set_cur_state: set the Current throttle state of the cooling device. .set_cur_state: set the Current throttle state of the cooling device.
1.2.2 void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev) 1.2.2 void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)
This interface function remove the thermal cooling device. This interface function remove the thermal cooling device.
It deletes the corresponding entry form /sys/class/thermal folder and unbind It deletes the corresponding entry form /sys/class/thermal folder and
itself from all the thermal zone devices using it. unbind itself from all the thermal zone devices using it.
1.3 interface for binding a thermal zone device with a thermal cooling device 1.3 interface for binding a thermal zone device with a thermal cooling device
1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz, 1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,
int trip, struct thermal_cooling_device *cdev); int trip, struct thermal_cooling_device *cdev);
This interface function bind a thermal cooling device to the certain trip point This interface function bind a thermal cooling device to the certain trip
of a thermal zone device. point of a thermal zone device.
This function is usually called in the thermal zone device .bind callback. This function is usually called in the thermal zone device .bind callback.
tz: the thermal zone device tz: the thermal zone device
cdev: thermal cooling device cdev: thermal cooling device
trip: indicates which trip point the cooling devices is associated with trip: indicates which trip point the cooling devices is associated with
in this thermal zone. in this thermal zone.
1.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz, 1.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,
int trip, struct thermal_cooling_device *cdev); int trip, struct thermal_cooling_device *cdev);
This interface function unbind a thermal cooling device from the certain trip point This interface function unbind a thermal cooling device from the certain
of a thermal zone device. trip point of a thermal zone device. This function is usually called in
This function is usually called in the thermal zone device .unbind callback. the thermal zone device .unbind callback.
tz: the thermal zone device tz: the thermal zone device
cdev: thermal cooling device cdev: thermal cooling device
trip: indicates which trip point the cooling devices is associated with trip: indicates which trip point the cooling devices is associated with
in this thermal zone. in this thermal zone.
2. sysfs attributes structure 2. sysfs attributes structure
...@@ -114,153 +114,157 @@ if hwmon is compiled in or built as a module. ...@@ -114,153 +114,157 @@ if hwmon is compiled in or built as a module.
Thermal zone device sys I/F, created once it's registered: Thermal zone device sys I/F, created once it's registered:
/sys/class/thermal/thermal_zone[0-*]: /sys/class/thermal/thermal_zone[0-*]:
|-----type: Type of the thermal zone |---type: Type of the thermal zone
|-----temp: Current temperature |---temp: Current temperature
|-----mode: Working mode of the thermal zone |---mode: Working mode of the thermal zone
|-----trip_point_[0-*]_temp: Trip point temperature |---trip_point_[0-*]_temp: Trip point temperature
|-----trip_point_[0-*]_type: Trip point type |---trip_point_[0-*]_type: Trip point type
Thermal cooling device sys I/F, created once it's registered: Thermal cooling device sys I/F, created once it's registered:
/sys/class/thermal/cooling_device[0-*]: /sys/class/thermal/cooling_device[0-*]:
|-----type : Type of the cooling device(processor/fan/...) |---type: Type of the cooling device(processor/fan/...)
|-----max_state: Maximum cooling state of the cooling device |---max_state: Maximum cooling state of the cooling device
|-----cur_state: Current cooling state of the cooling device |---cur_state: Current cooling state of the cooling device
These two dynamic attributes are created/removed in pairs. Then next two dynamic attributes are created/removed in pairs. They represent
They represent the relationship between a thermal zone and its associated cooling device. the relationship between a thermal zone and its associated cooling device.
They are created/removed for each They are created/removed for each successful execution of
thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device successful execution. thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device.
/sys/class/thermal/thermal_zone[0-*] /sys/class/thermal/thermal_zone[0-*]:
|-----cdev[0-*]: The [0-*]th cooling device in the current thermal zone |---cdev[0-*]: [0-*]th cooling device in current thermal zone
|-----cdev[0-*]_trip_point: Trip point that cdev[0-*] is associated with |---cdev[0-*]_trip_point: Trip point that cdev[0-*] is associated with
Besides the thermal zone device sysfs I/F and cooling device sysfs I/F, Besides the thermal zone device sysfs I/F and cooling device sysfs I/F,
the generic thermal driver also creates a hwmon sysfs I/F for each _type_ of the generic thermal driver also creates a hwmon sysfs I/F for each _type_
thermal zone device. E.g. the generic thermal driver registers one hwmon class device of thermal zone device. E.g. the generic thermal driver registers one hwmon
and build the associated hwmon sysfs I/F for all the registered ACPI thermal zones. class device and build the associated hwmon sysfs I/F for all the registered
ACPI thermal zones.
/sys/class/hwmon/hwmon[0-*]: /sys/class/hwmon/hwmon[0-*]:
|-----name: The type of the thermal zone devices. |---name: The type of the thermal zone devices
|-----temp[1-*]_input: The current temperature of thermal zone [1-*]. |---temp[1-*]_input: The current temperature of thermal zone [1-*]
|-----temp[1-*]_critical: The critical trip point of thermal zone [1-*]. |---temp[1-*]_critical: The critical trip point of thermal zone [1-*]
Please read Documentation/hwmon/sysfs-interface for additional information. Please read Documentation/hwmon/sysfs-interface for additional information.
*************************** ***************************
* Thermal zone attributes * * Thermal zone attributes *
*************************** ***************************
type Strings which represent the thermal zone type. type
This is given by thermal zone driver as part of registration. Strings which represent the thermal zone type.
Eg: "acpitz" indicates it's an ACPI thermal device. This is given by thermal zone driver as part of registration.
In order to keep it consistent with hwmon sys attribute, E.g: "acpitz" indicates it's an ACPI thermal device.
this should be a short, lowercase string, In order to keep it consistent with hwmon sys attribute; this should
not containing spaces nor dashes. be a short, lowercase string, not containing spaces nor dashes.
RO RO, Required
Required
temp
temp Current temperature as reported by thermal zone (sensor) Current temperature as reported by thermal zone (sensor).
Unit: millidegree Celsius Unit: millidegree Celsius
RO RO, Required
Required
mode
mode One of the predefined values in [kernel, user] One of the predefined values in [kernel, user].
This file gives information about the algorithm This file gives information about the algorithm that is currently
that is currently managing the thermal zone. managing the thermal zone. It can be either default kernel based
It can be either default kernel based algorithm algorithm or user space application.
or user space application. kernel = Thermal management in kernel thermal zone driver.
RW user = Preventing kernel thermal zone driver actions upon
Optional trip points so that user application can take full
kernel = Thermal management in kernel thermal zone driver. charge of the thermal management.
user = Preventing kernel thermal zone driver actions upon RW, Optional
trip points so that user application can take full
charge of the thermal management. trip_point_[0-*]_temp
The temperature above which trip point will be fired.
trip_point_[0-*]_temp The temperature above which trip point will be fired Unit: millidegree Celsius
Unit: millidegree Celsius RO, Optional
RO
Optional trip_point_[0-*]_type
Strings which indicate the type of the trip point.
trip_point_[0-*]_type Strings which indicate the type of the trip point E.g. it can be one of critical, hot, passive, active[0-*] for ACPI
E.g. it can be one of critical, hot, passive, thermal zone.
active[0-*] for ACPI thermal zone. RO, Optional
RO
Optional cdev[0-*]
Sysfs link to the thermal cooling device node where the sys I/F
cdev[0-*] Sysfs link to the thermal cooling device node where the sys I/F for cooling device throttling control represents.
for cooling device throttling control represents. RO, Optional
RO
Optional cdev[0-*]_trip_point
The trip point with which cdev[0-*] is associated in this thermal
cdev[0-*]_trip_point The trip point with which cdev[0-*] is associated in this thermal zone zone; -1 means the cooling device is not associated with any trip
-1 means the cooling device is not associated with any trip point. point.
RO RO, Optional
Optional
*****************************
****************************** * Cooling device attributes *
* Cooling device attributes * *****************************
******************************
type
type String which represents the type of device String which represents the type of device, e.g:
eg: For generic ACPI: this should be "Fan", - for generic ACPI: should be "Fan", "Processor" or "LCD"
"Processor" or "LCD" - for memory controller device on intel_menlow platform:
eg. For memory controller device on intel_menlow platform: should be "Memory controller".
this should be "Memory controller" RO, Required
RO
Required max_state
The maximum permissible cooling state of this cooling device.
max_state The maximum permissible cooling state of this cooling device. RO, Required
RO
Required cur_state
The current cooling state of this cooling device.
cur_state The current cooling state of this cooling device. The value can any integer numbers between 0 and max_state:
the value can any integer numbers between 0 and max_state, - cur_state == 0 means no cooling
cur_state == 0 means no cooling - cur_state == max_state means the maximum cooling.
cur_state == max_state means the maximum cooling. RW, Required
RW
Required
3. A simple implementation 3. A simple implementation
ACPI thermal zone may support multiple trip points like critical/hot/passive/active. ACPI thermal zone may support multiple trip points like critical, hot,
If an ACPI thermal zone supports critical, passive, active[0] and active[1] at the same time, passive, active. If an ACPI thermal zone supports critical, passive,
it may register itself as a thermal_zone_device (thermal_zone1) with 4 trip points in all. active[0] and active[1] at the same time, it may register itself as a
It has one processor and one fan, which are both registered as thermal_cooling_device. thermal_zone_device (thermal_zone1) with 4 trip points in all.
If the processor is listed in _PSL method, and the fan is listed in _AL0 method, It has one processor and one fan, which are both registered as
the sys I/F structure will be built like this: thermal_cooling_device.
If the processor is listed in _PSL method, and the fan is listed in _AL0
method, the sys I/F structure will be built like this:
/sys/class/thermal: /sys/class/thermal:
|thermal_zone1: |thermal_zone1:
|-----type: acpitz |---type: acpitz
|-----temp: 37000 |---temp: 37000
|-----mode: kernel |---mode: kernel
|-----trip_point_0_temp: 100000 |---trip_point_0_temp: 100000
|-----trip_point_0_type: critical |---trip_point_0_type: critical
|-----trip_point_1_temp: 80000 |---trip_point_1_temp: 80000
|-----trip_point_1_type: passive |---trip_point_1_type: passive
|-----trip_point_2_temp: 70000 |---trip_point_2_temp: 70000
|-----trip_point_2_type: active0 |---trip_point_2_type: active0
|-----trip_point_3_temp: 60000 |---trip_point_3_temp: 60000
|-----trip_point_3_type: active1 |---trip_point_3_type: active1
|-----cdev0: --->/sys/class/thermal/cooling_device0 |---cdev0: --->/sys/class/thermal/cooling_device0
|-----cdev0_trip_point: 1 /* cdev0 can be used for passive */ |---cdev0_trip_point: 1 /* cdev0 can be used for passive */
|-----cdev1: --->/sys/class/thermal/cooling_device3 |---cdev1: --->/sys/class/thermal/cooling_device3
|-----cdev1_trip_point: 2 /* cdev1 can be used for active[0]*/ |---cdev1_trip_point: 2 /* cdev1 can be used for active[0]*/
|cooling_device0: |cooling_device0:
|-----type: Processor |---type: Processor
|-----max_state: 8 |---max_state: 8
|-----cur_state: 0 |---cur_state: 0
|cooling_device3: |cooling_device3:
|-----type: Fan |---type: Fan
|-----max_state: 2 |---max_state: 2
|-----cur_state: 0 |---cur_state: 0
/sys/class/hwmon: /sys/class/hwmon:
|hwmon0: |hwmon0:
|-----name: acpitz |---name: acpitz
|-----temp1_input: 37000 |---temp1_input: 37000
|-----temp1_crit: 100000 |---temp1_crit: 100000
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