dt-bindings: arm: Explain capacities-dmips-mhz calculations in example

The example contains two values for the capacity currently, 446 in text
and 578 in code. The numbers are all correct but can confuse some of the
readers. This patch tries to explain how the numbers are calculated to
avoid same confusion going forward.

Acked-by: Daniel Lezcano <[email protected]>
Signed-off-by: Viresh Kumar <[email protected]>
Signed-off-by: Rob Herring <[email protected]>

diff --git a/Documentation/devicetree/bindings/arm/cpu-capacity.txt b/Documentation/devicetree/bindings/arm/cpu-capacity.txt
index 9b5685a1d15d9821efb9dd6d34a29ae1f788e31f..84262cdb8d29ae3f95ef94f6e7b9900897774c17 100644 (file)
--- a/Documentation/devicetree/bindings/arm/cpu-capacity.txt
+++ b/Documentation/devicetree/bindings/arm/cpu-capacity.txt
@@ -59,9 +59,11 @@ mhz values (normalized w.r.t. the highest value found while parsing the DT).
 ===========================================
 
 Example 1 (ARM 64-bit, 6-cpu system, two clusters):
-capacities-dmips-mhz are scaled w.r.t. 1024 (cpu@0 and cpu@1)
-supposing cluster0@max-freq=1100 and custer1@max-freq=850,
-final capacities are 1024 for cluster0 and 446 for cluster1
+The capacities-dmips-mhz or DMIPS/MHz values (scaled to 1024)
+are 1024 and 578 for cluster0 and cluster1. Further normalization
+is done by the operating system based on cluster0@max-freq=1100 and
+custer1@max-freq=850, final capacities are 1024 for cluster0 and
+446 for cluster1 (576*850/1100).
 
 cpus {
        #address-cells = <2>;