w1_ds2423.rst 2.4 KB

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  1. Kernel driver w1_ds2423
  2. =======================
  3. Supported chips:
  4. * Maxim DS2423 based counter devices.
  5. supported family codes:
  6. =============== ====
  7. W1_THERM_DS2423 0x1D
  8. =============== ====
  9. Author: Mika Laitio <[email protected]>
  10. Description
  11. -----------
  12. Support is provided through the sysfs w1_slave file. Each opening and
  13. read sequence of w1_slave file initiates the read of counters and ram
  14. available in DS2423 pages 12 - 15.
  15. Result of each page is provided as an ASCII output where each counter
  16. value and associated ram buffer is outpputed to own line.
  17. Each lines will contain the values of 42 bytes read from the counter and
  18. memory page along the crc=YES or NO for indicating whether the read operation
  19. was successful and CRC matched.
  20. If the operation was successful, there is also in the end of each line
  21. a counter value expressed as an integer after c=
  22. Meaning of 42 bytes represented is following:
  23. - 1 byte from ram page
  24. - 4 bytes for the counter value
  25. - 4 zero bytes
  26. - 2 bytes for crc16 which was calculated from the data read since the previous crc bytes
  27. - 31 remaining bytes from the ram page
  28. - crc=YES/NO indicating whether read was ok and crc matched
  29. - c=<int> current counter value
  30. example from the successful read::
  31. 00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
  32. 00 02 00 00 00 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
  33. 00 29 c6 5d 18 00 00 00 00 04 37 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=408798761
  34. 00 05 00 00 00 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=YES c=5
  35. example from the read with crc errors::
  36. 00 02 00 00 00 00 00 00 00 6d 38 00 ff ff 00 00 fe ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=YES c=2
  37. 00 02 00 00 22 00 00 00 00 e0 1f 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO
  38. 00 e1 61 5d 19 00 00 00 00 df 0b 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff 00 00 ff ff crc=NO
  39. 00 05 00 00 20 00 00 00 00 8d 39 ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff crc=NO