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Shawn Guo95ceafd2012-09-06 07:09:11 +00001Generic CPU0 cpufreq driver
2
3It is a generic cpufreq driver for CPU0 frequency management. It
4supports both uniprocessor (UP) and symmetric multiprocessor (SMP)
5systems which share clock and voltage across all CPUs.
6
7Both required and optional properties listed below must be defined
8under node /cpus/cpu@0.
9
10Required properties:
11- operating-points: Refer to Documentation/devicetree/bindings/power/opp.txt
12 for details
13
14Optional properties:
15- clock-latency: Specify the possible maximum transition latency for clock,
16 in unit of nanoseconds.
17- voltage-tolerance: Specify the CPU voltage tolerance in percentage.
18
19Examples:
20
21cpus {
22 #address-cells = <1>;
23 #size-cells = <0>;
24
25 cpu@0 {
26 compatible = "arm,cortex-a9";
27 reg = <0>;
28 next-level-cache = <&L2>;
29 operating-points = <
30 /* kHz uV */
31 792000 1100000
32 396000 950000
33 198000 850000
34 >;
35 transition-latency = <61036>; /* two CLK32 periods */
36 };
37
38 cpu@1 {
39 compatible = "arm,cortex-a9";
40 reg = <1>;
41 next-level-cache = <&L2>;
42 };
43
44 cpu@2 {
45 compatible = "arm,cortex-a9";
46 reg = <2>;
47 next-level-cache = <&L2>;
48 };
49
50 cpu@3 {
51 compatible = "arm,cortex-a9";
52 reg = <3>;
53 next-level-cache = <&L2>;
54 };
55};