lm70.rst 1.8 KB

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  1. Kernel driver lm70
  2. ==================
  3. Supported chips:
  4. * National Semiconductor LM70
  5. Datasheet: http://www.national.com/pf/LM/LM70.html
  6. * Texas Instruments TMP121/TMP123
  7. Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html
  8. * Texas Instruments TMP122/TMP124
  9. Information: https://www.ti.com/product/tmp122
  10. * National Semiconductor LM71
  11. Datasheet: https://www.ti.com/product/LM71
  12. * National Semiconductor LM74
  13. Datasheet: https://www.ti.com/product/LM74
  14. Author:
  15. Kaiwan N Billimoria <kaiwan@designergraphix.com>
  16. Description
  17. -----------
  18. This driver implements support for the National Semiconductor LM70
  19. temperature sensor.
  20. The LM70 temperature sensor chip supports a single temperature sensor.
  21. It communicates with a host processor (or microcontroller) via an
  22. SPI/Microwire Bus interface.
  23. Communication with the LM70 is simple: when the temperature is to be sensed,
  24. the driver accesses the LM70 using SPI communication: 16 SCLK cycles
  25. comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's
  26. complement digital temperature (sent via the SIO line), is available in the
  27. driver for interpretation. This driver makes use of the kernel's in-core
  28. SPI support.
  29. As a real (in-tree) example of this "SPI protocol driver" interfacing
  30. with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c
  31. and its associated documentation.
  32. The LM74 and TMP121/TMP122/TMP123/TMP124 are very similar; main difference is
  33. 13-bit temperature data (0.0625 degrees celsius resolution).
  34. The TMP122/TMP124 also feature configurable temperature thresholds.
  35. The LM71 is also very similar; main difference is 14-bit temperature
  36. data (0.03125 degrees celsius resolution).
  37. Thanks to
  38. ---------
  39. Jean Delvare <jdelvare@suse.de> for mentoring the hwmon-side driver
  40. development.