adm1025 2.3 KB

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  1. Kernel driver adm1025
  2. =====================
  3. Supported chips:
  4. * Analog Devices ADM1025, ADM1025A
  5. Prefix: 'adm1025'
  6. Addresses scanned: I2C 0x2c - 0x2e
  7. Datasheet: Publicly available at the Analog Devices website
  8. * Philips NE1619
  9. Prefix: 'ne1619'
  10. Addresses scanned: I2C 0x2c - 0x2d
  11. Datasheet: Publicly available at the Philips website
  12. The NE1619 presents some differences with the original ADM1025:
  13. * Only two possible addresses (0x2c - 0x2d).
  14. * No temperature offset register, but we don't use it anyway.
  15. * No INT mode for pin 16. We don't play with it anyway.
  16. Authors:
  17. Chen-Yuan Wu <gwu@esoft.com>,
  18. Jean Delvare <jdelvare@suse.de>
  19. Description
  20. -----------
  21. (This is from Analog Devices.) The ADM1025 is a complete system hardware
  22. monitor for microprocessor-based systems, providing measurement and limit
  23. comparison of various system parameters. Five voltage measurement inputs
  24. are provided, for monitoring +2.5V, +3.3V, +5V and +12V power supplies and
  25. the processor core voltage. The ADM1025 can monitor a sixth power-supply
  26. voltage by measuring its own VCC. One input (two pins) is dedicated to a
  27. remote temperature-sensing diode and an on-chip temperature sensor allows
  28. ambient temperature to be monitored.
  29. One specificity of this chip is that the pin 11 can be hardwired in two
  30. different manners. It can act as the +12V power-supply voltage analog
  31. input, or as the a fifth digital entry for the VID reading (bit 4). It's
  32. kind of strange since both are useful, and the reason for designing the
  33. chip that way is obscure at least to me. The bit 5 of the configuration
  34. register can be used to define how the chip is hardwired. Please note that
  35. it is not a choice you have to make as the user. The choice was already
  36. made by your motherboard's maker. If the configuration bit isn't set
  37. properly, you'll have a wrong +12V reading or a wrong VID reading. The way
  38. the driver handles that is to preserve this bit through the initialization
  39. process, assuming that the BIOS set it up properly beforehand. If it turns
  40. out not to be true in some cases, we'll provide a module parameter to force
  41. modes.
  42. This driver also supports the ADM1025A, which differs from the ADM1025
  43. only in that it has "open-drain VID inputs while the ADM1025 has on-chip
  44. 100k pull-ups on the VID inputs". It doesn't make any difference for us.