thmc50.rst 2.6 KB

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  1. Kernel driver thmc50
  2. =====================
  3. Supported chips:
  4. * Analog Devices ADM1022
  5. Prefix: 'adm1022'
  6. Addresses scanned: I2C 0x2c - 0x2e
  7. Datasheet: http://www.analog.com/en/prod/0,2877,ADM1022,00.html
  8. * Texas Instruments THMC50
  9. Prefix: 'thmc50'
  10. Addresses scanned: I2C 0x2c - 0x2e
  11. Datasheet: https://www.ti.com/
  12. Author: Krzysztof Helt <krzysztof.h1@wp.pl>
  13. This driver was derived from the 2.4 kernel thmc50.c source file.
  14. Credits:
  15. thmc50.c (2.4 kernel):
  16. - Frodo Looijaard <frodol@dds.nl>
  17. - Philip Edelbrock <phil@netroedge.com>
  18. Module Parameters
  19. -----------------
  20. * adm1022_temp3: short array
  21. List of adapter,address pairs to force chips into ADM1022 mode with
  22. second remote temperature. This does not work for original THMC50 chips.
  23. Description
  24. -----------
  25. The THMC50 implements: an internal temperature sensor, support for an
  26. external diode-type temperature sensor (compatible w/ the diode sensor inside
  27. many processors), and a controllable fan/analog_out DAC. For the temperature
  28. sensors, limits can be set through the appropriate Overtemperature Shutdown
  29. register and Hysteresis register. Each value can be set and read to half-degree
  30. accuracy. An alarm is issued (usually to a connected LM78) when the
  31. temperature gets higher then the Overtemperature Shutdown value; it stays on
  32. until the temperature falls below the Hysteresis value. All temperatures are in
  33. degrees Celsius, and are guaranteed within a range of -55 to +125 degrees.
  34. The THMC50 only updates its values each 1.5 seconds; reading it more often
  35. will do no harm, but will return 'old' values.
  36. The THMC50 is usually used in combination with LM78-like chips, to measure
  37. the temperature of the processor(s).
  38. The ADM1022 works the same as THMC50 but it is faster (5 Hz instead of
  39. 1 Hz for THMC50). It can be also put in a new mode to handle additional
  40. remote temperature sensor. The driver use the mode set by BIOS by default.
  41. In case the BIOS is broken and the mode is set incorrectly, you can force
  42. the mode with additional remote temperature with adm1022_temp3 parameter.
  43. A typical symptom of wrong setting is a fan forced to full speed.
  44. Driver Features
  45. ---------------
  46. The driver provides up to three temperatures:
  47. temp1
  48. - internal
  49. temp2
  50. - remote
  51. temp3
  52. - 2nd remote only for ADM1022
  53. pwm1
  54. - fan speed (0 = stop, 255 = full)
  55. pwm1_mode
  56. - always 0 (DC mode)
  57. The value of 0 for pwm1 also forces FAN_OFF signal from the chip,
  58. so it stops fans even if the value 0 into the ANALOG_OUT register does not.
  59. The driver was tested on Compaq AP550 with two ADM1022 chips (one works
  60. in the temp3 mode), five temperature readings and two fans.