1 SPEAr cpufreq driver 1 SPEAr cpufreq driver
2 ------------------- 2 -------------------
3 3
4 SPEAr SoC cpufreq driver for CPU frequency sca 4 SPEAr SoC cpufreq driver for CPU frequency scaling.
5 It supports both uniprocessor (UP) and symmetr 5 It supports both uniprocessor (UP) and symmetric multiprocessor (SMP) systems
6 which share clock across all CPUs. 6 which share clock across all CPUs.
7 7
8 Required properties: 8 Required properties:
9 - cpufreq_tbl: Table of frequencies CPU could 9 - cpufreq_tbl: Table of frequencies CPU could be transitioned into, in the
10 increasing order. 10 increasing order.
11 11
12 Optional properties: 12 Optional properties:
13 - clock-latency: Specify the possible maximum 13 - clock-latency: Specify the possible maximum transition latency for clock, in
14 unit of nanoseconds. 14 unit of nanoseconds.
15 15
16 Both required and optional properties listed a 16 Both required and optional properties listed above must be defined under node
17 /cpus/cpu@0. 17 /cpus/cpu@0.
18 18
19 Examples: 19 Examples:
20 -------- 20 --------
21 cpus { 21 cpus {
22 22
23 <...> 23 <...>
24 24
25 cpu@0 { 25 cpu@0 {
26 compatible = "arm,cortex-a9"; 26 compatible = "arm,cortex-a9";
27 reg = <0>; 27 reg = <0>;
28 28
29 <...> 29 <...>
30 30
31 cpufreq_tbl = < 166000 31 cpufreq_tbl = < 166000
32 200000 32 200000
33 250000 33 250000
34 300000 34 300000
35 400000 35 400000
36 500000 36 500000
37 600000 >; 37 600000 >;
38 }; 38 };
39 39
40 <...> 40 <...>
41 41
42 }; 42 };
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.