1 PPC4xx Clock Power Management (CPM) node 1 PPC4xx Clock Power Management (CPM) node
2 2
3 Required properties: 3 Required properties:
4 - compatible : compatible l 4 - compatible : compatible list, currently only "ibm,cpm"
5 - dcr-access-method : "native" 5 - dcr-access-method : "native"
6 - dcr-reg : < DCR regist 6 - dcr-reg : < DCR register range >
7 7
8 Optional properties: 8 Optional properties:
9 - er-offset : All 4xx SoCs 9 - er-offset : All 4xx SoCs with a CPM controller have
10 one of two d 10 one of two different order for the CPM
11 registers. S 11 registers. Some have the CPM registers
12 in the follo 12 in the following order (ER,FR,SR). The
13 others have 13 others have them in the following order
14 (SR,ER,FR). 14 (SR,ER,FR). For the second case set
15 er-offset = 15 er-offset = <1>.
16 - unused-units : specifier co 16 - unused-units : specifier consist of one cell. For each
17 bit in the c 17 bit in the cell, the corresponding bit
18 in CPM will 18 in CPM will be set to turn off unused
19 devices. 19 devices.
20 - idle-doze : specifier co 20 - idle-doze : specifier consist of one cell. For each
21 bit in the c 21 bit in the cell, the corresponding bit
22 in CPM will 22 in CPM will be set to turn off unused
23 devices. Thi 23 devices. This is usually just CPM[CPU].
24 - standby : specifier co 24 - standby : specifier consist of one cell. For each
25 bit in the c 25 bit in the cell, the corresponding bit
26 in CPM will 26 in CPM will be set on standby and
27 restored on 27 restored on resume.
28 - suspend : specifier co 28 - suspend : specifier consist of one cell. For each
29 bit in the c 29 bit in the cell, the corresponding bit
30 in CPM will 30 in CPM will be set on suspend (mem) and
31 restored on 31 restored on resume. Note, for standby
32 and suspend 32 and suspend the corresponding bits can
33 be different 33 be different or the same. Usually for
34 standby only 34 standby only class 2 and 3 units are set.
35 However, the 35 However, the interface does not care.
36 If they are 36 If they are the same, the additional
37 power saving 37 power saving will be seeing if support
38 is available 38 is available to put the DDR in self
39 refresh mode 39 refresh mode and any additional power
40 saving techn 40 saving techniques for the specific SoC.
41 41
42 Example: 42 Example:
43 CPM0: cpm { 43 CPM0: cpm {
44 compatible = "ibm,cpm"; 44 compatible = "ibm,cpm";
45 dcr-access-method = "native"; 45 dcr-access-method = "native";
46 dcr-reg = <0x160 0x003>; 46 dcr-reg = <0x160 0x003>;
47 er-offset = <0>; 47 er-offset = <0>;
48 unused-units = <0x00000100>; 48 unused-units = <0x00000100>;
49 idle-doze = <0x02000000>; 49 idle-doze = <0x02000000>;
50 standby = <0xfeff0000>; 50 standby = <0xfeff0000>;
51 suspend = <0xfeff791d>; 51 suspend = <0xfeff791d>;
52 }; 52 };
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