The thermal code uses int, long and unsigned long for temperatures
in different places.
Using an unsigned type limits the thermal framework to positive
temperatures without need. Also several drivers currently will report
temperatures near UINT_MAX for temperatures below 0°C. This will probably
immediately shut the machine down due to overtemperature if started below
0°C.
'long' is 64bit on several architectures. This is not needed since INT_MAX °mC
is above the melting point of all known materials.
Consistently use a plain 'int' for temperatures throughout the thermal code and
the drivers. This only changes the places in the drivers where the temperature
is passed around as pointer, when drivers internally use another type this is
not changed.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Acked-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Reviewed-by: Peter Feuerer <peter@piie.net>
Cc: Punit Agrawal <punit.agrawal@arm.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: Jean Delvare <jdelvare@suse.de>
Cc: Peter Feuerer <peter@piie.net>
Cc: Heiko Stuebner <heiko@sntech.de>
Cc: Lukasz Majewski <l.majewski@samsung.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: linux-acpi@vger.kernel.org
Cc: platform-driver-x86@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-omap@vger.kernel.org
Cc: linux-samsung-soc@vger.kernel.org
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Maxime Ripard <maxime.ripard@free-electrons.com>
Cc: Darren Hart <dvhart@infradead.org>
Cc: lm-sensors@lm-sensors.org
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
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>
The power allocator governor is a thermal governor that controls system
and device power allocation to control temperature. Conceptually, the
implementation divides the sustainable power of a thermal zone among
all the heat sources in that zone.
This governor relies on "power actors", entities that represent heat
sources. They can report current and maximum power consumption and
can set a given maximum power consumption, usually via a cooling
device.
The governor uses a Proportional Integral Derivative (PID) controller
driven by the temperature of the thermal zone. The output of the
controller is a power budget that is then allocated to each power
actor that can have bearing on the temperature we are trying to
control. It decides how much power to give each cooling device based
on the performance they are requesting. The PID controller ensures
that the total power budget does not exceed the control temperature.
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Javi Merino <javi.merino@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Add three optional callbacks to the cooling device interface to allow
them to express power. In addition to the callbacks, add helpers to
identify cooling devices that implement the power cooling device API.
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>
A governor may need to store its current state between calls to
throttle(). That state depends on the thermal zone, so store it as
private data in struct thermal_zone_device.
The governors may have two new ops: bind_to_tz() and unbind_from_tz().
When provided, these functions let governors do some initialization
and teardown when they are bound/unbound to a tz and possibly store that
information in the governor_data field of the struct
thermal_zone_device.
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>
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>
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>
When CONFIG_THERMAL is not enabled, it is better to introduce
equivalent dummy functions in the exported header than to
introduce #ifdeffery in drivers using the function.
This will prevent issues such as that reported in:
http://www.spinics.net/lists/linux-next/msg31573.html
While at it switch over to IS_ENABLED for thermal macros
to allow for thermal framework to be built as framework
and relevant APIs be usable by relevant drivers as a result.
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Nishanth Menon <nm@ti.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
The size of unsigned long varies between 32 and 64 bit systems while
the size of phandle arguments is always 32 bits per parameter.
On 64-bit systems, cooling devices registered via of-thermal apis fail
to bind when the min/max cooling state is specified as
THERMAL_NO_LIMIT (-1UL) as there is a mis-match between the value read
from the device tree (32bit) and the pre-processor define (64bit).
As we're unlikely to need cooling states larger than 32 bits, and for
consistency with the size of phandle arguments, explicitly limit
THERMAL_NO_LIMIT to 32 bits.
Reported-by: Hyungwoo Yang <hwoo.yang@gmail.com>
Acked-by: Zhang Rui <rui.zhang@intel.com>
Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
include/linux/thermal.h contains definitions for the Thermal generic
netlink family, but none of the valuable information relevant to
user-space such as the Genl family name, multicast group, version or
command set and data types is exported to user-space.
Export all the relevant generic netlink information to user-space to
make this genl family usable by user-space, and while at it, export
THERMAL_NAME_LENGTH since it limits name length for thermal_hwmon
devices.
Kbuild and MAINTAINERS are also updated accordingly to reflect this new
file: include/uapi/linux/thermal.h.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Before this change it was only possible to set get_temp() and get_trend()
methods to be used in the common code handling passing parameters via
device tree to "cpu-thermal" CPU thermal zone device.
Now it is possible to also set emulated value of temperature for debug
purposes.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Acked-by: Eduardo Valentin <edubezval@gmail.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
This patch changes name of struct __thermal_trip to thermal_trip and moves
declaration of the latter to ./include/linux/thermal.h for better visibility.
Signed-off-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
Different drivers request API extensions in of-thermal. For this reason,
additional callbacks are required to fit the new drivers needs.
The current API implementation expects the registering sensor driver
to provide a get_temp and get_trend callbacks as function parameters.
As the amount of callbacks is growing, this patch changes the existing
implementation to use a .ops field to hold all the of thermal callbacks
to sensor drivers.
This patch also changes the existing of-thermal users to fit the new
API design. No functional change is introduced in this patch.
Cc: Alexandre Courbot <gnurou@gmail.com>
Cc: devicetree@vger.kernel.org
Cc: Grant Likely <grant.likely@linaro.org>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jean Delvare <jdelvare@suse.de>
Cc: linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org
Cc: linux-tegra@vger.kernel.org
Cc: lm-sensors@lm-sensors.org
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Cc: Thierry Reding <thierry.reding@gmail.com>
Cc: Zhang Rui <rui.zhang@intel.com>
Acked-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Mikko Perttunen <mikko.perttunen@kapsi.fi>
Reviewed-by: Mikko Perttunen <mikko.perttunen@kapsi.fi>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>
ACPI INT3402 device object could report temperature for the memory module.
To expose such information to user space, a thermal zone device is registered
for it so that the thermal sysfs interface can expose such information for
userspace to use.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This macro can be used by other component so move it to a common header,
but in a slightly different way: define two macros, one macro with an
offset and the other doesn't.
Signed-off-by: Aaron Lu <aaron.lu@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch adds a new API to allow registering cooling devices
in the thermal framework derived from device tree nodes.
This API links the cooling device with the device tree node
so that binding with thermal zones is possible, given
that thermal zones are pointing to cooling device
device tree nodes.
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>
This patch introduces a device tree bindings for
describing the hardware thermal behavior and limits.
Also a parser to read and interpret the data and feed
it in the thermal framework is presented.
This patch introduces a thermal data parser for device
tree. The parsed data is used to build thermal zones
and thermal binding parameters. The output data
can then be used to deploy thermal policies.
This patch adds also documentation regarding this
API and how to define tree nodes to use
this infrastructure.
Note that, in order to be able to have control
on the sensor registration on the DT thermal zone,
it was required to allow changing the thermal zone
.get_temp callback. For this reason, this patch
also removes the 'const' modifier from the .ops
field of thermal zone devices.
Cc: Zhang Rui <rui.zhang@intel.com>
Cc: linux-pm@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
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>
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>
Pull thermal management update from Zhang Rui:
"The most important one is to build thermal core and governor and cpu
cooling code into one module. This fixes a regression that thermal
core does not work if it is built as module, since 3.7. I'll backport
them to stable kernel once those changes are in upstream.
The largest batch is the thermal kernel-doc & coding style
updates/cleanups from Eduardo.
Highlights:
- build all thermal framework code into one module to fix a
regression that thermal does not work if it is built as module.
- Marvell Armada 370/XP thermal sensor driver
- thermal core/cpu cooling kernel-doc & coding style updates and
cleanups.
- Add Eduardo Valentin as thermal sub-maintainer, both in mailing
list and patchwork. He will help me on arm thermal drivers."
* 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/rzhang/linux: (68 commits)
thermal: db8500_cpufreq_cooling: remove usage of IS_ERR_OR_NULL()
thermal: thermal_core: remove usage of IS_ERR_OR_NULL
thermal: cpu_cooling: improve line breaking
thermal: cpu_cooling: alignment improvements
thermal: cpu_cooling: remove checkpatch.pl warning
thermal: cpu_cooling: remove trailing blank line
thermal: cpu_cooling: align on open parenthesis
thermal: cpu_cooling: standardize comment style
thermal: cpu_cooling: standardize end of function
thermal: cpu_cooling: remove trailing white spaces
Thermal: update documentation for thermal_zone_device_register
thermal: update kernel-doc for thermal_zone_device_register
thermal: update kernel-doc for create_trip_attrs
thermal: update kernel-doc for thermal_cooling_device_register
thermal: update kernel-doc for thermal_zone_unbind_cooling_device
thermal: update kernel-doc for thermal_zone_bind_cooling_device
thermal: use EXPORT_SYMBOL_GPL
thermal: rename notify_thermal_framework to thermal_notify_framework
thermal: update driver license
thermal: use strlcpy instead of strcpy
...
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>
This patch exports the thermal_zone_get_temp API so that driver
writers can fetch temperature of thermal zones managed by other
drivers.
Acked-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch adds a helper function to get a reference of
a thermal zone, based on the zone type name.
It will perform a zone name lookup and return a reference
to a thermal zone device that matches the name requested.
In case the zone is not found or when several zones match
same name or if the required parameters are invalid, it will return
the corresponding error code (ERR_PTR).
Cc: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
Acked-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
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>
The following warning is obtained when CONFIG_NET is not defined:
In file included from drivers/thermal/mvebu_thermal.c:27:0:
include/linux/thermal.h:254:12: warning: 'thermal_generate_netlink_event'
defined but not used [-Wunused-function]
This patch fixes the warning by properly inlining
thermal_generate_netlink_event().
Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
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>
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>
These two new thermal_trend types are used to tell the governor
that the temeprature is raising/dropping quickly.
Thermal cooling governors should handle this situation and make
proper decisions, e.g. set cooling state to upper/lower limit directly
instead of one step each time.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch adds a notification API which the sensor drivers'
can use to notify the framework. The framework then takes
care of the throttling according to the configured policy.
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch makes the thermal_cdev_update function as a
global one, so that other files can use it. This function
serves as a single arbitrator to set the state of a cooling
device.
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch creates a structure to hold platform
thermal governor information, and provides APIs
for individual thermal governors to register/unregister
with the Thermal framework.
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch adds the thermal zone parameter as an argument to
the tzd_register() function call; and updates other drivers
using this function.
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch adds platform level information to thermal.h
by introducing two structures to hold:
* bind parameters for a thermal zone,
* zone level platform parameters
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch adds the following API's to thermal_sys.c, that
can be used by other Thermal drivers.
* get_tz_trend: obtain the trend of the given thermal zone
* get_thermal_instance: obtain the instance corresponding
to the given tz, cdev and the trip point.
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
This patch rearranges the code in thermal.h file,
in the following order, so that it is easy to
read/maintain.
1. All #defines
2. All enums
3. All fops structures
4. All device structures
5. All function declarations
Signed-off-by: Durgadoss R <durgadoss.r@intel.com>
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
we need to go over all the thermal_instance list of a cooling device
to decide which cooling state to put the cooling device to.
But at this time, as a cooling device may be referenced in multiple
thermal zones, we need to lock the list first in case
another thermal zone is updating this cooling 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>
Remove thermal_zone_device_passive(). And use
thermal_zone_trip_update() and thermal_zone_do_update()
for both active and passive cooling.
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>
This fixes the problem that a cooling device may be referenced by
by multiple trip points in multiple thermal zones.
With this patch, we have two stages for updating a thermal zone,
1. check if a thermal_instance needs to be updated or not
2. update the cooling device, based on the target cooling state
of all its instances.
Note that, currently, the cooling device is set to the deepest
cooling state required.
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>
List thermal_instance in thermal_cooling_device so that
cooling device can know the cooling state requirement
of all the thermal instances.
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>
Rename thermal_zone_device.cooling_devices
to thermal_zone_device.thermal_instances
thermal_zone_device.cooling_devices is not accurate
as this is a list for thermal instances, rather than cooling devices.
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>
Remove tc1/tc2 in generic thermal layer.
.get_trend() callback starts to take effect from this patch.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Valentin, Eduardo <eduardo.valentin@ti.com>
According to ACPI spec, tc1 and tc2 are used by OSPM
to anticipate the temperature trends.
We introduced the same concept to the generic thermal layer
for passive cooling, but now it seems that these values
are hard to be used on other platforms.
So We introduce .get_trend() as a more general solution.
For the platform thermal drivers that have their own way to
anticipate the temperature trends, they should provide
their own .get_trend() callback.
Or else, we will calculate the temperature trends by simply
comparing the current temperature and the cached previous
temperature reading.
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reviewed-by: Rafael J. Wysocki <rjw@sisk.pl>
Reviewed-by: Valentin, Eduardo <eduardo.valentin@ti.com>
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>
