aboutsummaryrefslogtreecommitdiff
path: root/Documentation/thermal/sysfs-api.txt
AgeCommit message (Collapse)Author
2018-04-02thermal: Add cooling device's statistics in sysfsViresh Kumar
This extends the sysfs interface for thermal cooling devices and exposes some pretty useful statistics. These statistics have proven to be quite useful specially while doing benchmarks related to the task scheduler, where we want to make sure that nothing has disrupted the test, specially the cooling device which may have put constraints on the CPUs. The information exposed here tells us to what extent the CPUs were constrained by the thermal framework. The write-only "reset" file is used to reset the statistics. The read-only "time_in_state_ms" file shows the time (in msec) spent by the device in the respective cooling states, and it prints one line per cooling state. The read-only "total_trans" file shows single positive integer value showing the total number of cooling state transitions the device has gone through since the time the cooling device is registered or the time when statistics were reset last. The read-only "trans_table" file shows a two dimensional matrix, where an entry <i,j> (row i, column j) represents the number of transitions from State_i to State_j. This is how the directory structure looks like for a single cooling device: $ ls -R /sys/class/thermal/cooling_device0/ /sys/class/thermal/cooling_device0/: cur_state max_state power stats subsystem type uevent /sys/class/thermal/cooling_device0/power: autosuspend_delay_ms runtime_active_time runtime_suspended_time control runtime_status /sys/class/thermal/cooling_device0/stats: reset time_in_state_ms total_trans trans_table This is tested on ARM 64-bit Hisilicon hikey620 board running Ubuntu and ARM 64-bit Hisilicon hikey960 board running Android. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2017-05-05thermal: core: Add a back up thermal shutdown mechanismKeerthy
orderly_poweroff is triggered when a graceful shutdown of system is desired. This may be used in many critical states of the kernel such as when subsystems detects conditions such as critical temperature conditions. However, in certain conditions in system boot up sequences like those in the middle of driver probes being initiated, userspace will be unable to power off the system in a clean manner and leaves the system in a critical state. In cases like these, the /sbin/poweroff will return success (having forked off to attempt powering off the system. However, the system overall will fail to completely poweroff (since other modules will be probed) and the system is still functional with no userspace (since that would have shut itself off). However, there is no clean way of detecting such failure of userspace powering off the system. In such scenarios, it is necessary for a backup workqueue to be able to force a shutdown of the system when orderly shutdown is not successful after a configurable time period. Reported-by: Nishanth Menon <nm@ti.com> Signed-off-by: Keerthy <j-keerthy@ti.com> Acked-by: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2016-09-27thermal: Add support for hardware-tracked trip pointsSascha Hauer
This adds support for hardware-tracked trip points to the device tree thermal sensor framework. The framework supports an arbitrary number of trip points. Whenever the current temperature is updated, the trip points immediately below and above the current temperature are found. A .set_trips callback is then called with the temperatures. If there is no trip point above or below the current temperature, the passed trip temperature will be -INT_MAX or INT_MAX respectively. In this callback, the driver should program the hardware such that it is notified when either of these trip points are triggered. When a trip point is triggered, the driver should call `thermal_zone_device_update' for the respective thermal zone. This will cause the trip points to be updated again. If .set_trips is not implemented, the framework behaves as before. This patch is based on an earlier version from Mikko Perttunen <mikko.perttunen@kapsi.fi> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de> Signed-off-by: Caesar Wang <wxt@rock-chips.com> Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: linux-pm@vger.kernel.org Reviewed-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2016-09-27thermal: core: export apis to get slope and offsetRajendra Nayak
Add apis for platform thermal drivers to query for slope and offset attributes, which might be needed for temperature calculations. Signed-off-by: Rajendra Nayak <rnayak@codeaurora.org> Signed-off-by: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2016-05-17thermal: Syntactic and factual errors in the API documentAndy Champ
There are several places where the English in the document is syntactically invalid, or unclear. There are also one or two factual errors. Reviewed-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Andy Champ <andycham@amazon.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2016-03-09thermal: doc: Add details of devm_thermal_zone_of_sensor_{register,unregister}Laxman Dewangan
Add details of the interface devm_thermal_zone_of_sensor_register() and devm_thermal_zone_of_sensor_unregister() in the <thermal/sysfs-api.txt>. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2016-03-09thermal: doc: Add details of thermal_zone_of_sensor_{register,unregister}Laxman Dewangan
Add details of the interface thermal_zone_of_sensor_register() and thermal_zone_of_sensor_unregister() in the thermal/sysfs-api.txt. The details describes the functionality and parameter which are passed to these interfaces. Signed-off-by: Laxman Dewangan <ldewangan@nvidia.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2016-01-14thermal: add description for integral_cutoff unitLeo Yan
Add more explicitly description for unit of integral_cutoff which used by power allocator governor. Signed-off-by: Leo Yan <leo.yan@linaro.org> Acked-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2015-08-03thermal: add available policies sysfs attributeNi Wade
The Linux thermal framework support to change thermal governor policy in userspace, but it can't show what available policies supported. This patch adds available_policies attribute to the thermal framework, it can list the thermal governors which can be used for a particular zone. This attribute is read only. Signed-off-by: Wei Ni <wni@nvidia.com> Reviewed-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2015-05-11thermal: support slope and offset coefficientsEduardo Valentin
It is common to have a linear extrapolation from the current sensor readings and the actual temperature value. This is specially the case when the sensor is in use to extrapolate hotspots. This patch adds slope and offset constants for single sensor linear extrapolation equation. Because the same sensor can be use in different locations, from board to board, these constants are added as part of thermal_zone_params. The constants are available through sysfs. It is up to the device driver to determine the usage of these values. Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-05-04thermal: export thermal_zone_parameters to sysfsJavi Merino
It's useful for tuning to be able to edit thermal_zone_parameters from userspace. Export them to the thermal_zone sysfs so that they can be easily changed. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-05-04thermal: fair_share: generalize the weight conceptJavi Merino
The fair share governor has the concept of weights, which is the influence of each cooling device in a thermal zone. The current implementation forces the weights of all cooling devices in a thermal zone to add up to a 100. This complicates setups, as you need to know in advance how many cooling devices you are going to have. If you bind a new cooling device, you have to modify all the other cooling devices weights, which is error prone. Furthermore, you can't specify a "default" weight for platforms since that default value depends on the number of cooling devices in the platform. This patch generalizes the concept of weight by allowing any number to be a "weight". Weights are now relative to each other. Platforms that don't specify weights get the same default value for all their cooling devices, so all their cdevs are considered to be equally influential. It's important to note that previous users of the weights don't need to alter the code: percentages continue to work as they used to. This patch just removes the constraint of all the weights in a thermal zone having to add up to a 100. If they do, you get the same behavior as before. If they don't, fair share now works for that platform. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Durgadoss R <durgadoss.r@intel.com> Acked-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-05-04thermal: export weight to sysfsJavi Merino
It's useful to have access to the weights for the cooling devices for thermal zones and change them if needed. Export them to sysfs. Cc: Zhang Rui <rui.zhang@intel.com> Cc: Eduardo Valentin <edubezval@gmail.com> Signed-off-by: Javi Merino <javi.merino@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2015-05-04thermal: of: fix cooling device weights in device treeKapileshwar Singh
Currently you can specify the weight of the cooling device in the device tree but that information is not populated to the thermal_bind_params where the fair share governor expects it to be. The of thermal zone device doesn't have a thermal_bind_params structure and arguably it's better to pass the weight inside the thermal_instance as it is specific to the bind of a cooling device to a thermal zone parameter. Core thermal code is fixed to populate the weight in the instance from the thermal_bind_params, so platform code that was passing the weight inside the thermal_bind_params continue to work seamlessly. While we are at it, create a default value for the weight parameter for those thermal zones that currently don't define it and remove the hardcoded default in of-thermal. Cc: Zhang Rui <rui.zhang@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: Len Brown <lenb@kernel.org> Cc: Peter Feuerer <peter@piie.net> Cc: Darren Hart <dvhart@infradead.org> Cc: Eduardo Valentin <edubezval@gmail.com> Cc: Kukjin Kim <kgene@kernel.org> Cc: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Kapileshwar Singh <kapileshwar.singh@arm.com> Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
2013-09-03thermal: thermal_core: allow binding with limits on bind_paramsEduardo Valentin
When registering a thermal zone device using platform information via bind_params, the thermal framework will always perform the cdev binding using the lowest and highest limits (THERMAL_NO_LIMIT). This patch changes the data structures so that it is possible to inform what are the desired limits for each trip point inside a bind_param. The way the binding is performed is also changed so that it uses the new data structure. Cc: Zhang Rui <rui.zhang@intel.com> Cc: linux-pm@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
2013-09-03drivers: thermal: make usage of CONFIG_THERMAL_HWMON optionalEduardo Valentin
When registering a new thermal_device, the thermal framework will always add a hwmon sysfs interface. This patch adds a flag to make this behavior optional. Now when registering a new thermal device, the caller can optionally inform if hwmon interface is desirable. This can be done by means of passing a thermal_zone_params.no_hwmon == true. In order to keep same behavior as of today, all current calls will by default create the hwmon interface. Cc: David Woodhouse <dwmw2@infradead.org> Cc: linux-acpi@vger.kernel.org Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Cc: linux-pm@vger.kernel.org Cc: Zhang Rui <rui.zhang@intel.com> Suggested-by: Wei Ni <wni@nvidia.com> Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
2013-04-27Thermal: update documentation for thermal_zone_device_registerZhang Rui
Update kernel Documentation for thermal_zone_device_register. Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2013-04-25thermal: rename notify_thermal_framework to thermal_notify_frameworkEduardo Valentin
To follow the prefix names used by the thermal functions, this patch renames notify_thermal_framework to thermal_notify_framework. Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2013-04-14Thermal: build thermal governors into thermal_sys moduleZhang Rui
The thermal governors are part of the thermal framework, rather than a seperate feature/module. Because the generic thermal layer can not work without thermal governors, and it must load the thermal governors during its initialization. Build them into one module in this patch. This also fix a problem that the generic thermal layer does not work when CONFIG_THERMAL=m and CONFIG_THERMAL_GOV_XXX=y. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Acked-by: Eduardo Valentin <eduardo.valentin@ti.com> Acked-by: Durgadoss R <durgadoss.r@intel.com>
2013-04-02thermal: add a warning for temperature emulation featureEduardo Valentin
Because this feature is for debuging purposes, it is highly recommended to do not enable this on production systems. This patch adds warnings for system integrators, so that people are aware of this potential security issue. Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2013-02-06thermal: sysfs: Add a new sysfs node emul_temp for thermal emulationAmit Daniel Kachhap
This patch adds support to set the emulated temperature method in thermal zone (sensor). After setting this feature thermal zone may report this temperature and not the actual temperature. The emulation implementation may be based on sensor capability through platform specific handler or pure software emulation if no platform handler defined. This is useful in debugging different temperature threshold and its associated cooling action. Critical threshold's cannot be emulated. Writing 0 on this node should disable emulation. Signed-off-by: Amit Daniel Kachhap <amit.daniel@samsung.com> Acked-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2013-01-16thermal: Use thermal zone device id in netlink messagesEduardo Valentin
This patch changes the function thermal_generate_netlink_event to receive a thermal zone device instead of a originator id. This way, the messages will always be bound to a thermal zone. Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com> Reviewed-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2012-11-05Thermal: Add documentation for platform layer dataDurgadoss R
This patch adds documentation for thermal_bind_params and thermal_zone_params structures. Also, adds details on EXPORT_SYMBOL APIs. Signed-off-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
2012-09-24Thermal: set upper and lower limitsZhang Rui
set upper and lower limits when binding a thermal cooling device to a thermal zone device. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl> Reviewed-by: Eduardo Valentin <eduardo.valentin@ti.com>
2012-07-24Thermal: Documentation updateZhang Rui
With commit 6503e5df08008b9a47022b5e9ebba658c8fa69af, the value of /sys/class/thermal/thermal_zoneX/mode has been changed from user/kernel to enabled/disabled. Update the documentation so that users won't be confused. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2012-07-24Thermal: Add Hysteresis attributesDurgadoss R
The Linux Thermal Framework does not support hysteresis attributes. Most thermal sensors, today, have a hysteresis value associated with trip points. This patch adds hysteresis attributes on a per-trip-point basis, to the Thermal Framework. These attributes are optionally writable. Signed-off-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2012-07-24Thermal: Make Thermal trip points writeableDurgadoss R
Some of the thermal drivers using the Generic Thermal Framework require (all/some) trip points to be writeable. This patch makes the trip point temperatures writeable on a per-trip point basis, and modifies the required function call in thermal.c. This patch also updates the Documentation to reflect the new change. Signed-off-by: Durgadoss R <durgadoss.r@intel.com> Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2012-01-23thermal: Rename generate_netlink_eventJean Delvare
It doesn't seem right for the thermal subsystem to export a symbol named generate_netlink_event. This function is thermal-specific and its name should reflect that fact. Rename it to thermal_generate_netlink_event. Signed-off-by: Jean Delvare <khali@linux-fr.org> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: R.Durgadoss <durgadoss.r@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2011-01-12thermal: Add event notification to thermal frameworkR.Durgadoss
This patch adds event notification support to the generic thermal sysfs framework in the kernel. The notification is in the form of a netlink event. Signed-off-by: R.Durgadoss <durgadoss.r@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2009-11-05thermal: add sanity check for the passive attributeFrans Pop
Values below 1000 milli-celsius don't make sense and can cause the system to go into a thermal heart attack: the actual temperature will always be lower and thus the system will be throttled down to its lowest setting. An additional problem is that values below 1000 will show as 0 in /proc/acpi/thermal/TZx/trip_points:passive. cat passive 0 echo -n 90 >passive bash: echo: write error: Invalid argument echo -n 90000 >passive cat passive 90000 Signed-off-by: Frans Pop <elendil@planet.nl> Acked-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
2009-11-05thermal: sysfs-api.txt - document passive attribute for thermal zonesFrans Pop
Signed-off-by: Frans Pop <elendil@planet.nl> Acked-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
2009-11-05thermal: sysfs-api.txt - reformat for improved readabilityFrans Pop
The document currently uses large indentations which make the text too wide for easy readability. Also improve general consistency. Signed-off-by: Frans Pop <elendil@planet.nl> Acked-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Len Brown <len.brown@intel.com>
2008-04-29thermal: update the documentationZhang Rui
Update the documentation for the thermal driver hwmon sys I/F. Change the ACPI thermal zone type to be consistent with hwmon. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Acked-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Len Brown <len.brown@intel.com>
2008-03-13thermal: fix generic thermal I/F for hwmonZhang, Rui
Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-07ACPI: thermal: syntax, spelling, kernel-docLen Brown
Reviewed-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Len Brown <len.brown@intel.com>
2008-02-01the generic thermal sysfs driverZhang Rui
The Generic Thermal sysfs driver for thermal management. Signed-off-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Thomas Sujith <sujith.thomas@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>