cpm.txt 1.8 KB

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