[4.4.y-cip 12/15] devicetree: bindings: Add optional dynamic-power-coefficient property


Chen-Yu Tsai (Moxa) <wens@...>
 

From: Punit Agrawal <punit.agrawal@arm.com>

commit 3be3f8f36e7349006f19c8c8f0d686e98462a993 upstream.

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 =3D 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>
Signed-off-by: Chen-Yu Tsai (Moxa) <wens@csie.org>
---
Documentation/devicetree/bindings/arm/cpus.txt | 17 +++++++++++++++++
1 file changed, 17 insertions(+)

diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentati=
on/devicetree/bindings/arm/cpus.txt
index 9ef9a2089a5e7..6b1d8ebb94b7b 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 descr=
ibed below.
Definition: Specifies the syscon node controlling the cpu core
power domains.
=20
+ - 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 =3D dynamic-power-coefficient * V^2 * f
+
+ where voltage is in uV, frequency is in MHz.
+
Example 1 (dual-cluster big.LITTLE system 32-bit):
=20
cpus {
--=20
2.27.0.rc0

Join cip-dev@lists.cip-project.org to automatically receive all group messages.