ti-gpmc.txt 2.7 KB

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  1. Device tree bindings for OMAP general purpose memory controllers (GPMC)
  2. The actual devices are instantiated from the child nodes of a GPMC node.
  3. Required properties:
  4. - compatible: Should be set to one of the following:
  5. ti,omap2420-gpmc (omap2420)
  6. ti,omap2430-gpmc (omap2430)
  7. ti,omap3430-gpmc (omap3430 & omap3630)
  8. ti,omap4430-gpmc (omap4430 & omap4460 & omap543x)
  9. ti,am3352-gpmc (am335x devices)
  10. - reg: A resource specifier for the register space
  11. (see the example below)
  12. - ti,hwmods: Should be set to "ti,gpmc" until the DT transition is
  13. completed.
  14. - #address-cells: Must be set to 2 to allow memory address translation
  15. - #size-cells: Must be set to 1 to allow CS address passing
  16. - gpmc,num-cs: The maximum number of chip-select lines that controller
  17. can support.
  18. - gpmc,num-waitpins: The maximum number of wait pins that controller can
  19. support.
  20. - ranges: Must be set up to reflect the memory layout with four
  21. integer values for each chip-select line in use:
  22. <cs-number> 0 <physical address of mapping> <size>
  23. Currently, calculated values derived from the contents
  24. of the per-CS register GPMC_CONFIG7 (as set up by the
  25. bootloader) are used for the physical address decoding.
  26. As this will change in the future, filling correct
  27. values here is a requirement.
  28. Timing properties for child nodes. All are optional and default to 0.
  29. - gpmc,sync-clk: Minimum clock period for synchronous mode, in picoseconds
  30. Chip-select signal timings corresponding to GPMC_CONFIG2:
  31. - gpmc,cs-on: Assertion time
  32. - gpmc,cs-rd-off: Read deassertion time
  33. - gpmc,cs-wr-off: Write deassertion time
  34. ADV signal timings corresponding to GPMC_CONFIG3:
  35. - gpmc,adv-on: Assertion time
  36. - gpmc,adv-rd-off: Read deassertion time
  37. - gpmc,adv-wr-off: Write deassertion time
  38. WE signals timings corresponding to GPMC_CONFIG4:
  39. - gpmc,we-on: Assertion time
  40. - gpmc,we-off: Deassertion time
  41. OE signals timings corresponding to GPMC_CONFIG4:
  42. - gpmc,oe-on: Assertion time
  43. - gpmc,oe-off: Deassertion time
  44. Access time and cycle time timings corresponding to GPMC_CONFIG5:
  45. - gpmc,page-burst-access: Multiple access word delay
  46. - gpmc,access: Start-cycle to first data valid delay
  47. - gpmc,rd-cycle: Total read cycle time
  48. - gpmc,wr-cycle: Total write cycle time
  49. The following are only applicable to OMAP3+ and AM335x:
  50. - gpmc,wr-access
  51. - gpmc,wr-data-mux-bus
  52. Example for an AM33xx board:
  53. gpmc: gpmc@50000000 {
  54. compatible = "ti,am3352-gpmc";
  55. ti,hwmods = "gpmc";
  56. reg = <0x50000000 0x2000>;
  57. interrupts = <100>;
  58. gpmc,num-cs = <8>;
  59. gpmc,num-waitpins = <2>;
  60. #address-cells = <2>;
  61. #size-cells = <1>;
  62. ranges = <0 0 0x08000000 0x10000000>; /* CS0 @addr 0x8000000, size 0x10000000 */
  63. /* child nodes go here */
  64. };