diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/powerpc/dts-bindings/4xx/cpm.txt | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/Documentation/powerpc/dts-bindings/4xx/cpm.txt b/Documentation/powerpc/dts-bindings/4xx/cpm.txt new file mode 100644 index 000000000000..ee459806d35e --- /dev/null +++ b/Documentation/powerpc/dts-bindings/4xx/cpm.txt | |||
| @@ -0,0 +1,52 @@ | |||
| 1 | PPC4xx Clock Power Management (CPM) node | ||
| 2 | |||
| 3 | Required properties: | ||
| 4 | - compatible : compatible list, currently only "ibm,cpm" | ||
| 5 | - dcr-access-method : "native" | ||
| 6 | - dcr-reg : < DCR register range > | ||
| 7 | |||
| 8 | Optional properties: | ||
| 9 | - er-offset : All 4xx SoCs with a CPM controller have | ||
| 10 | one of two different order for the CPM | ||
| 11 | registers. Some have the CPM registers | ||
| 12 | in the following order (ER,FR,SR). The | ||
| 13 | others have them in the following order | ||
| 14 | (SR,ER,FR). For the second case set | ||
| 15 | er-offset = <1>. | ||
| 16 | - unused-units : specifier consist of one cell. For each | ||
| 17 | bit in the cell, the corresponding bit | ||
| 18 | in CPM will be set to turn off unused | ||
| 19 | devices. | ||
| 20 | - idle-doze : specifier consist of one cell. For each | ||
| 21 | bit in the cell, the corresponding bit | ||
| 22 | in CPM will be set to turn off unused | ||
| 23 | devices. This is usually just CPM[CPU]. | ||
| 24 | - standby : specifier consist of one cell. For each | ||
| 25 | bit in the cell, the corresponding bit | ||
| 26 | in CPM will be set on standby and | ||
| 27 | restored on resume. | ||
| 28 | - suspend : specifier consist of one cell. For each | ||
| 29 | bit in the cell, the corresponding bit | ||
| 30 | in CPM will be set on suspend (mem) and | ||
| 31 | restored on resume. Note, for standby | ||
| 32 | and suspend the corresponding bits can | ||
| 33 | be different or the same. Usually for | ||
| 34 | standby only class 2 and 3 units are set. | ||
| 35 | However, the interface does not care. | ||
| 36 | If they are the same, the additional | ||
| 37 | power saving will be seeing if support | ||
| 38 | is available to put the DDR in self | ||
| 39 | refresh mode and any additional power | ||
| 40 | saving techniques for the specific SoC. | ||
| 41 | |||
| 42 | Example: | ||
| 43 | CPM0: cpm { | ||
| 44 | compatible = "ibm,cpm"; | ||
| 45 | dcr-access-method = "native"; | ||
| 46 | dcr-reg = <0x160 0x003>; | ||
| 47 | er-offset = <0>; | ||
| 48 | unused-units = <0x00000100>; | ||
| 49 | idle-doze = <0x02000000>; | ||
| 50 | standby = <0xfeff0000>; | ||
| 51 | suspend = <0xfeff791d>; | ||
| 52 | }; | ||