From: Punit Agrawal <punit.agrawal@arm.com>
Date: Tue, 17 Nov 2015 12:06:21 +0000 (+0000)
Subject: UPSTREAM: devicetree: bindings: Add optional dynamic-power-coefficient property
X-Git-Tag: firefly_0821_release~2659
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=a772af0b7053c2d728b9ffacdea4f0adee2ca69b;p=firefly-linux-kernel-4.4.55.git
UPSTREAM: 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.
Change-Id: Ib208ff2f83ee45911e846f940952d765ae8c974e
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>
Signed-off-by: Finley Xiao <finley.xiao@rock-chips.com>
(cherry picked from commit 3be3f8f36e7349006f19c8c8f0d686e98462a993)
---
diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
index 58e240d75169..c352c11bd641 100644
--- a/Documentation/devicetree/bindings/arm/cpus.txt
+++ b/Documentation/devicetree/bindings/arm/cpus.txt
@@ -243,6 +243,23 @@ 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 {