amc6821.rst 3.3 KB

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  1. Kernel driver amc6821
  2. =====================
  3. Supported chips:
  4. Texas Instruments AMC6821
  5. Prefix: 'amc6821'
  6. Addresses scanned: 0x18, 0x19, 0x1a, 0x2c, 0x2d, 0x2e, 0x4c, 0x4d, 0x4e
  7. Datasheet: http://focus.ti.com/docs/prod/folders/print/amc6821.html
  8. Authors:
  9. Tomaz Mertelj <tomaz.mertelj@guest.arnes.si>
  10. Description
  11. -----------
  12. This driver implements support for the Texas Instruments amc6821 chip.
  13. The chip has one on-chip and one remote temperature sensor and one pwm fan
  14. regulator.
  15. The pwm can be controlled either from software or automatically.
  16. The driver provides the following sensor accesses in sysfs:
  17. ======================= == ===============================================
  18. temp1_input ro on-chip temperature
  19. temp1_min rw "
  20. temp1_max rw "
  21. temp1_crit rw "
  22. temp1_min_alarm ro "
  23. temp1_max_alarm ro "
  24. temp1_crit_alarm ro "
  25. temp2_input ro remote temperature
  26. temp2_min rw "
  27. temp2_max rw "
  28. temp2_crit rw "
  29. temp2_min_alarm ro "
  30. temp2_max_alarm ro "
  31. temp2_crit_alarm ro "
  32. temp2_fault ro "
  33. fan1_input ro tachometer speed
  34. fan1_min rw "
  35. fan1_max rw "
  36. fan1_fault ro "
  37. fan1_div rw Fan divisor can be either 2 or 4.
  38. pwm1 rw pwm1
  39. pwm1_enable rw regulator mode, 1=open loop, 2=fan controlled
  40. by remote temperature, 3=fan controlled by
  41. combination of the on-chip temperature and
  42. remote-sensor temperature,
  43. pwm1_auto_channels_temp ro 1 if pwm_enable==2, 3 if pwm_enable==3
  44. pwm1_auto_point1_pwm ro Hardwired to 0, shared for both
  45. temperature channels.
  46. pwm1_auto_point2_pwm rw This value is shared for both temperature
  47. channels.
  48. pwm1_auto_point3_pwm rw Hardwired to 255, shared for both
  49. temperature channels.
  50. temp1_auto_point1_temp ro Hardwired to temp2_auto_point1_temp
  51. which is rw. Below this temperature fan stops.
  52. temp1_auto_point2_temp rw The low-temperature limit of the proportional
  53. range. Below this temperature
  54. pwm1 = pwm1_auto_point2_pwm. It can go from
  55. 0 degree C to 124 degree C in steps of
  56. 4 degree C. Read it out after writing to get
  57. the actual value.
  58. temp1_auto_point3_temp rw Above this temperature fan runs at maximum
  59. speed. It can go from temp1_auto_point2_temp.
  60. It can only have certain discrete values
  61. which depend on temp1_auto_point2_temp and
  62. pwm1_auto_point2_pwm. Read it out after
  63. writing to get the actual value.
  64. temp2_auto_point1_temp rw Must be between 0 degree C and 63 degree C and
  65. it defines the passive cooling temperature.
  66. Below this temperature the fan stops in
  67. the closed loop mode.
  68. temp2_auto_point2_temp rw The low-temperature limit of the proportional
  69. range. Below this temperature
  70. pwm1 = pwm1_auto_point2_pwm. It can go from
  71. 0 degree C to 124 degree C in steps
  72. of 4 degree C.
  73. temp2_auto_point3_temp rw Above this temperature fan runs at maximum
  74. speed. It can only have certain discrete
  75. values which depend on temp2_auto_point2_temp
  76. and pwm1_auto_point2_pwm. Read it out after
  77. writing to get actual value.
  78. ======================= == ===============================================
  79. Module parameters
  80. -----------------
  81. If your board has a BIOS that initializes the amc6821 correctly, you should
  82. load the module with: init=0.
  83. If your board BIOS doesn't initialize the chip, or you want
  84. different settings, you can set the following parameters:
  85. - init=1,
  86. - pwminv: 0 default pwm output, 1 inverts pwm output.