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authorPunit Agrawal <punit.agrawal@arm.com>2015-11-17 13:06:21 +0100
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2015-12-10 00:14:58 +0100
commit3be3f8f36e7349006f19c8c8f0d686e98462a993 (patch)
tree2b9161eeb4766f9d18d207167a8e8f803dea5145
parentcpufreq: governor: Use lockless timer function (diff)
downloadlinux-3be3f8f36e7349006f19c8c8f0d686e98462a993.tar.xz
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devicetree: bindings: Add optional dynamic-power-coefficient property
The dynamic power consumption of a device is proportional to the square of voltage (V) and the clock frequency (f). It can be expressed as Pdyn = dynamic-power-coefficient * V^2 * f. The coefficient represents the running time dynamic power consumption in units of mw/MHz/uVolt^2 and can be used in the above formula to calculate the dynamic power in mW. Signed-off-by: Punit Agrawal <punit.agrawal@arm.com> Acked-by: Rob Herring <robh@kernel.org> Reviewed-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--Documentation/devicetree/bindings/arm/cpus.txt17
1 files changed, 17 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
index 3a07a87fef20..6aca64f289b6 100644
--- a/Documentation/devicetree/bindings/arm/cpus.txt
+++ b/Documentation/devicetree/bindings/arm/cpus.txt
@@ -242,6 +242,23 @@ nodes to be present and contain the properties described below.
Definition: Specifies the syscon node controlling the cpu core
power domains.
+ - dynamic-power-coefficient
+ Usage: optional
+ Value type: <prop-encoded-array>
+ Definition: A u32 value that represents the running time dynamic
+ power coefficient in units of mW/MHz/uVolt^2. The
+ coefficient can either be calculated from power
+ measurements or derived by analysis.
+
+ The dynamic power consumption of the CPU is
+ proportional to the square of the Voltage (V) and
+ the clock frequency (f). The coefficient is used to
+ calculate the dynamic power as below -
+
+ Pdyn = dynamic-power-coefficient * V^2 * f
+
+ where voltage is in uV, frequency is in MHz.
+
Example 1 (dual-cluster big.LITTLE system 32-bit):
cpus {