lm70 1.6 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. * National Semiconductor LM71
  9. Datasheet: http://www.ti.com/product/LM71
  10. * National Semiconductor LM74
  11. Datasheet: http://www.ti.com/product/LM74
  12. Author:
  13. Kaiwan N Billimoria <kaiwan@designergraphix.com>
  14. Description
  15. -----------
  16. This driver implements support for the National Semiconductor LM70
  17. temperature sensor.
  18. The LM70 temperature sensor chip supports a single temperature sensor.
  19. It communicates with a host processor (or microcontroller) via an
  20. SPI/Microwire Bus interface.
  21. Communication with the LM70 is simple: when the temperature is to be sensed,
  22. the driver accesses the LM70 using SPI communication: 16 SCLK cycles
  23. comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's
  24. complement digital temperature (sent via the SIO line), is available in the
  25. driver for interpretation. This driver makes use of the kernel's in-core
  26. SPI support.
  27. As a real (in-tree) example of this "SPI protocol driver" interfacing
  28. with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c
  29. and its associated documentation.
  30. The LM74 and TMP121/TMP123 are very similar; main difference is 13-bit
  31. temperature data (0.0625 degrees celsius resolution).
  32. The LM71 is also very similar; main difference is 14-bit temperature
  33. data (0.03125 degrees celsius resolution).
  34. Thanks to
  35. ---------
  36. Jean Delvare <jdelvare@suse.de> for mentoring the hwmon-side driver
  37. development.