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Commit 26b6f223 authored by Len Brown's avatar Len Brown
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Merge branches 'release' and 'menlo' into release 



Conflicts:

	drivers/acpi/video.c

Signed-off-by: default avatarLen Brown <len.brown@intel.com>
parents e5e54bc8 e5e54bc8 3c602840

Documentation/thermal/sysfs-api.txt

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Generic Thermal Sysfs driver How To

=========================



Written by Sujith Thomas <sujith.thomas@intel.com>, Zhang Rui <rui.zhang@intel.com>



Updated: 2 January 2008



Copyright (c)  2008 Intel Corporation





0. Introduction



The generic thermal sysfs provides a set of interfaces for thermal zone devices (sensors)

and thermal cooling devices (fan, processor...) to register with the thermal management

solution and to be a part of it.



This how-to focusses on enabling new thermal zone and cooling devices to participate

in thermal management.

This solution is platform independent and any type of thermal zone devices 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

as cooling device attributes to the user space.

An intelligent thermal management application can make decisions based on inputs

from thermal zone attributes (the current temperature and trip point temperature)

and throttle appropriate devices.



[0-*]	denotes any positive number starting from 0

[1-*]	denotes any positive number starting from 1



1. thermal sysfs driver interface functions



1.1 thermal zone device interface

1.1.1 struct thermal_zone_device *thermal_zone_device_register(char *name, int trips,

				void *devdata, struct thermal_zone_device_ops *ops)



	This interface function adds a new thermal zone device (sensor) to

	/sys/class/thermal folder as thermal_zone[0-*].

	It tries to bind all the thermal cooling devices registered at the same time.



	name: the thermal zone name.

	trips: the total number of trip points this thermal zone supports.

	devdata: device private data

	ops: thermal zone device callbacks.

		.bind: bind the thermal zone device with a thermal cooling device.

		.unbind: unbing the thermal zone device with a thermal cooling device.

		.get_temp: get the current temperature of the thermal zone.

		.get_mode: get the current mode (user/kernel) of the thermal zone.

			   "kernel" means thermal management is done in kernel.

			   "user" will prevent kernel thermal driver actions upon trip points

			   so that user applications can take charge of thermal management.

		.set_mode: set the mode (user/kernel) of the thermal zone.

		.get_trip_type: get the type of certain trip point.

		.get_trip_temp: get the temperature above which the certain trip point

				will be fired.



1.1.2 void thermal_zone_device_unregister(struct thermal_zone_device *tz)



	This interface function removes the thermal zone device.

	It deletes the corresponding entry form /sys/class/thermal folder and unbind all

	the thermal cooling devices it uses.



1.2 thermal cooling device interface

1.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char *name,

					void *devdata, struct thermal_cooling_device_ops *)



	This interface function adds a new thermal cooling device (fan/processor/...) to

	/sys/class/thermal/ folder as cooling_device[0-*].

	It tries to bind itself to all the thermal zone devices register at the same time.

	name: the cooling device name.

	devdata: device private data.

	ops: thermal cooling devices callbacks.

		.get_max_state: get the Maximum 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.



1.2.2 void thermal_cooling_device_unregister(struct thermal_cooling_device *cdev)



	This interface function remove the thermal cooling device.

	It deletes the corresponding entry form /sys/class/thermal folder and unbind

	itself from all	the thermal zone devices using it.



1.3 interface for binding a thermal zone device with a thermal cooling device

1.3.1 int thermal_zone_bind_cooling_device(struct thermal_zone_device *tz,

			int trip, struct thermal_cooling_device *cdev);



	This interface function bind a thermal cooling device to the certain trip point

	of a thermal zone device.

	This function is usually called in the thermal zone device .bind callback.

	tz: the thermal zone device

	cdev: thermal cooling device

	trip: indicates which trip point the cooling devices is associated with

		 in this thermal zone.



1.3.2 int thermal_zone_unbind_cooling_device(struct thermal_zone_device *tz,

				int trip, struct thermal_cooling_device *cdev);



	This interface function unbind a thermal cooling device from the certain trip point

	of a thermal zone device.

	This function is usually called in the thermal zone device .unbind callback.

	tz: the thermal zone device

	cdev: thermal cooling device

	trip: indicates which trip point the cooling devices is associated with

		in this thermal zone.



2. sysfs attributes structure



RO	read only value

RW	read/write value



All thermal sysfs attributes will be represented under /sys/class/thermal

/sys/class/thermal/



Thermal zone device sys I/F, created once it's registered:

|thermal_zone[0-*]:

	|-----type:			Type of the thermal zone

	|-----temp:			Current temperature

	|-----mode:			Working mode of the thermal zone

	|-----trip_point_[0-*]_temp:	Trip point temperature

	|-----trip_point_[0-*]_type:	Trip point type



Thermal cooling device sys I/F, created once it's registered:

|cooling_device[0-*]:

	|-----type :			Type of the cooling device(processor/fan/...)

	|-----max_state:		Maximum cooling state of the cooling device

	|-----cur_state:		Current cooling state of the cooling device





These two dynamic attributes are created/removed in pairs.

They represent the relationship between a thermal zone and its associated cooling device.

They are created/removed for each

thermal_zone_bind_cooling_device/thermal_zone_unbind_cooling_device successful exection.



|thermal_zone[0-*]

	|-----cdev[0-*]:		The [0-*]th cooling device in the current thermal zone

	|-----cdev[0-*]_trip_point:	Trip point that cdev[0-*] is associated with





***************************

* Thermal zone attributes *

***************************



type				Strings which represent the thermal zone type.

				This is given by thermal zone driver as part of registration.

				Eg: "ACPI thermal zone" indicates it's a ACPI thermal device

				RO

				Optional



temp				Current temperature as reported by thermal zone (sensor)

				Unit: degree celsius

				RO

				Required



mode				One of the predifned values in [kernel, user]

				This file gives information about the algorithm

				that is currently managing the thermal zone.

				It can be either default kernel based algorithm

				or user space application.

				RW

				Optional

				kernel	= Thermal management in kernel thermal zone driver.

				user	= Preventing kernel thermal zone driver actions upon

					  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

				Unit: degree celsius

				RO

				Optional



trip_point_[0-*]_type 		Strings which indicate the type of the trip point

				Eg. it can be one of critical, hot, passive,

				    active[0-*] for ACPI thermal zone.

				RO

				Optional



cdev[0-*]			Sysfs link to the thermal cooling device node where the sys I/F

				for cooling device throttling control represents.

				RO

				Optional



cdev[0-*]_trip_point		The trip point with which cdev[0-*] is assocated in this thermal zone

				-1 means the cooling device is not associated with any trip point.

				RO

				Optional



******************************

* Cooling device  attributes *

******************************



type				String which represents the type of device

				eg: For generic ACPI: this should be "Fan",

				"Processor" or "LCD"

				eg. For memory controller device on intel_menlow platform:

				this should be "Memory controller"

				RO

				Optional



max_state			The maximum permissible cooling state of this cooling device.

				RO

				Required



cur_state			The current cooling state of this cooling device.

				the value can any integer numbers between 0 and max_state,

				cur_state == 0 means no cooling

				cur_state == max_state means the maximum cooling.

				RW

				Required



3. A simple implementation



ACPI thermal zone may support multiple trip points like critical/hot/passive/active.

If an ACPI thermal zone supports critical, passive, active[0] and active[1] at the same time,

it may register itself as a thermale_zone_device (thermal_zone1) with 4 trip points in all.

It has one processor and one fan, which are both registered as 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:



|thermal_zone1:

	|-----type:			ACPI thermal zone

	|-----temp:			37

	|-----mode:			kernel

	|-----trip_point_0_temp:	100

	|-----trip_point_0_type:	critical

	|-----trip_point_1_temp:	80

	|-----trip_point_1_type:	passive

	|-----trip_point_2_temp:	70

	|-----trip_point_2_type:	active[0]

	|-----trip_point_3_temp:	60

	|-----trip_point_3_type:	active[1]

	|-----cdev0:			--->/sys/class/thermal/cooling_device0

	|-----cdev0_trip_point:		1	/* cdev0 can be used for passive */

	|-----cdev1:			--->/sys/class/thermal/cooling_device3

	|-----cdev1_trip_point:		2	/* cdev1 can be used for active[0]*/



|cooling_device0:

	|-----type:			Processor

	|-----max_state:		8

	|-----cur_state:		0



|cooling_device3:

	|-----type:			Fan

	|-----max_state:		2

	|-----cur_state:		0

drivers/Kconfig

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@@ -60,6 +60,8 @@ source "drivers/power/Kconfig" 




source "drivers/hwmon/Kconfig"

source "drivers/hwmon/Kconfig"





source "drivers/thermal/Kconfig"



source "drivers/watchdog/Kconfig"

source "drivers/watchdog/Kconfig"





source "drivers/ssb/Kconfig"

source "drivers/ssb/Kconfig"

drivers/Makefile

+1 −0
Original line number Original line Diff line number Diff line
@@ -65,6 +65,7 @@ obj-y += i2c/ 
obj-$(CONFIG_W1)		+= w1/

obj-$(CONFIG_W1)		+= w1/

obj-$(CONFIG_POWER_SUPPLY)	+= power/

obj-$(CONFIG_POWER_SUPPLY)	+= power/

obj-$(CONFIG_HWMON)		+= hwmon/

obj-$(CONFIG_HWMON)		+= hwmon/

obj-$(CONFIG_THERMAL)		+= thermal/

obj-$(CONFIG_WATCHDOG)		+= watchdog/

obj-$(CONFIG_WATCHDOG)		+= watchdog/

obj-$(CONFIG_PHONE)		+= telephony/

obj-$(CONFIG_PHONE)		+= telephony/

obj-$(CONFIG_MD)		+= md/

obj-$(CONFIG_MD)		+= md/

drivers/acpi/Kconfig

+1 −0
Original line number Original line Diff line number Diff line
@@ -186,6 +186,7 @@ config ACPI_HOTPLUG_CPU 
config ACPI_THERMAL

config ACPI_THERMAL

	tristate "Thermal Zone"

	tristate "Thermal Zone"

	depends on ACPI_PROCESSOR

	depends on ACPI_PROCESSOR

	select THERMAL

	default y

	default y

	help

	help

	  This driver adds support for ACPI thermal zones.  Most mobile and

	  This driver adds support for ACPI thermal zones.  Most mobile and

drivers/acpi/bus.c

+25 −0
Original line number Original line Diff line number Diff line
@@ -122,6 +122,31 @@ int acpi_bus_get_status(struct acpi_device *device) 




EXPORT_SYMBOL(acpi_bus_get_status);

EXPORT_SYMBOL(acpi_bus_get_status);





void acpi_bus_private_data_handler(acpi_handle handle,

				   u32 function, void *context)

{

	return;

}

EXPORT_SYMBOL(acpi_bus_private_data_handler);



int acpi_bus_get_private_data(acpi_handle handle, void **data)

{

	acpi_status status = AE_OK;



	if (!*data)

		return -EINVAL;



	status = acpi_get_data(handle, acpi_bus_private_data_handler, data);

	if (ACPI_FAILURE(status) || !*data) {

		ACPI_DEBUG_PRINT((ACPI_DB_INFO, "No context for object [%p]\n",

				handle));

		return -ENODEV;

	}



	return 0;

}

EXPORT_SYMBOL(acpi_bus_get_private_data);



/* --------------------------------------------------------------------------

/* --------------------------------------------------------------------------

                                 Power Management

                                 Power Management

   -------------------------------------------------------------------------- */

   -------------------------------------------------------------------------- */