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- PPC4xx Clock Power Management (CPM) node
- Required properties:
- - compatible : compatible list, currently only "ibm,cpm"
- - dcr-access-method : "native"
- - dcr-reg : < DCR register range >
- Optional properties:
- - er-offset : All 4xx SoCs with a CPM controller have
- one of two different order for the CPM
- registers. Some have the CPM registers
- in the following order (ER,FR,SR). The
- others have them in the following order
- (SR,ER,FR). For the second case set
- er-offset = <1>.
- - unused-units : specifier consist of one cell. For each
- bit in the cell, the corresponding bit
- in CPM will be set to turn off unused
- devices.
- - idle-doze : specifier consist of one cell. For each
- bit in the cell, the corresponding bit
- in CPM will be set to turn off unused
- devices. This is usually just CPM[CPU].
- - standby : specifier consist of one cell. For each
- bit in the cell, the corresponding bit
- in CPM will be set on standby and
- restored on resume.
- - suspend : specifier consist of one cell. For each
- bit in the cell, the corresponding bit
- in CPM will be set on suspend (mem) and
- restored on resume. Note, for standby
- and suspend the corresponding bits can
- be different or the same. Usually for
- standby only class 2 and 3 units are set.
- However, the interface does not care.
- If they are the same, the additional
- power saving will be seeing if support
- is available to put the DDR in self
- refresh mode and any additional power
- saving techniques for the specific SoC.
- Example:
- CPM0: cpm {
- compatible = "ibm,cpm";
- dcr-access-method = "native";
- dcr-reg = <0x160 0x003>;
- er-offset = <0>;
- unused-units = <0x00000100>;
- idle-doze = <0x02000000>;
- standby = <0xfeff0000>;
- suspend = <0xfeff791d>;
- };
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