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
Cc: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Eduardo Valentin <redacted>
---

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.