On Tue, Nov 12, 2013 at 07:46:04PM +0000, Eduardo Valentin wrote: > 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@xxxxxxxxx> > Cc: linux-pm@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Cc: Mark Rutland <mark.rutland@xxxxxxx> > Signed-off-by: Eduardo Valentin <eduardo.valentin@xxxxxx> > --- > > Hello all, > > Very minor changes from v8 to v9. > > Changelog: > > - Rephrase a couple of sentences in the binding document > - Fixed a couple of property types in the binding document > - Removed the constant macro definitions for trip type. This > change also affected the bindings posted on patches 09/14/15. > > .../devicetree/bindings/thermal/thermal.txt | 586 ++++++++++++++ > drivers/thermal/Kconfig | 13 + > drivers/thermal/Makefile | 1 + > drivers/thermal/of-thermal.c | 849 +++++++++++++++++++++ > drivers/thermal/thermal_core.c | 9 +- > drivers/thermal/thermal_core.h | 9 + > include/dt-bindings/thermal/thermal.h | 17 + > include/linux/thermal.h | 28 +- > 8 files changed, 1509 insertions(+), 3 deletions(-) > create mode 100644 Documentation/devicetree/bindings/thermal/thermal.txt > create mode 100644 drivers/thermal/of-thermal.c > create mode 100644 include/dt-bindings/thermal/thermal.h > > diff --git a/Documentation/devicetree/bindings/thermal/thermal.txt b/Documentation/devicetree/bindings/thermal/thermal.txt > new file mode 100644 > index 0000000..59f5bd2 > --- /dev/null > +++ b/Documentation/devicetree/bindings/thermal/thermal.txt > @@ -0,0 +1,586 @@ > +* Thermal Framework Device Tree descriptor > + > +This file describes a generic binding to provide a way of > +defining hardware thermal structure using device tree. > +A thermal structure includes thermal zones and their components, > +such as trip points, polling intervals, sensors and cooling devices > +binding descriptors. > + > +The target of device tree thermal descriptors is to describe only > +the hardware thermal aspects. The thermal device tree bindings are > +not about how the system must control or which algorithm or policy > +must be taken in place. > + > +There are five types of nodes involved to describe thermal bindings: > +- thermal sensors: devices which may be used to take temperature > + measurements. > +- cooling devices: devices which may be used to dissipate heat. > +- trip points: describe key temperatures at which cooling is recommended. The > + set of points should be chosen based on hardware limits. > +- cooling maps: used to describe links between trip points and cooling devices; > +- thermal zones: used to describe thermal data within the hardware; > + > +The following is a description of each of these node types. > + > +* Thermal sensor devices > + > +Thermal sensor devices are nodes providing temperature sensing capabilities on > +thermal zones. Typical devices are I2C ADC converters and bandgaps. These are > +nodes providing temperature data to thermal zones. Thermal sensor devices may > +control one or more internal sensors. > + > +Required property: > +- #thermal-sensor-cells: Used to provide sensor device specific information > + Type: unsigned while referring to it. Typically 0 on thermal sensor > + Size: one cell nodes with only one sensor, and at least 1 on nodes > + with several internal sensors, in order > + to identify uniquely the sensor instances within > + the IC. See thermal zone binding for more details > + on how consumers refer to sensor devices. > + > +* Cooling device nodes > + > +Cooling devices are nodes providing control on power dissipation. There > +are essentially two ways to provide control on power dissipation. First > +is by means of regulating device performance, which is known as passive > +cooling. A typical passive cooling is a CPU that has dynamic voltage and > +frequency scaling (DVFS), and uses lower frequencies as cooling states. > +Second is by means of activating devices in order to remove > +the dissipated heat, which is known as active cooling, e.g. regulating > +fan speeds. In both cases, cooling devices shall have a way to determine > +the state of cooling in which the device is. > + > +Required properties: > +- cooling-min-state: An integer indicating the smallest > + Type: unsigned cooling state accepted. Typically 0. > + Size: one cell > + > +- cooling-max-state: An integer indicating the largest > + Type: unsigned cooling state accepted. > + Size: one cell > + > +- #cooling-cells: Used to provide cooling device specific information > + Type: unsigned while referring to it. Must be at least 2, in order > + Size: one cell to specify minimum and maximum cooling state used > + in the reference. The first cell is the minimum > + cooling state requested and the second cell is > + the maximum cooling state requested in the reference. > + See Cooling device maps section below for more details > + on how consumers refer to cooling devices. This is the point I'm still most concerned with, as it provides a definite meaning to an otherwise abstract property. However, if you believe this is sane and unlikely to be problematic, then I am happy to leave the decision to you. > + > +* Trip points > + > +The trip node is a node to describe a point in the temperature domain > +in which the system takes an action. This node describes just the point, > +not the action. > + > +Required properties: > +- temperature: An integer indicating the trip temperature level, > + Type: signed in millicelsius. > + Size: one cell > + > +- hysteresis: A low hysteresis value on temperature property (above). > + Type: unsigned This is a relative value, in millicelsius. > + Size: one cell > + > +- type: a string containing the trip type. Supported values are: Get rid of the "Supported", that's a Linux detail. s/Supported/expected/ ? Given the discussion has otherwise boiled down to bits that I think can change later, I'm happy to give my ack: Acked-by: Mark Rutland <mark.rutland@xxxxxxx> I'll leave it to the others to fight against this if they still have concerns. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
