Documentation/hwmon/lm70

   1 Kernel driver lm70
   2 ==================
   3
   4 Supported chips:
   5   * National Semiconductor LM70
   6     Datasheet: http://www.national.com/pf/LM/LM70.html
   7   * Texas Instruments TMP121/TMP123
   8     Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html
   9   * National Semiconductor LM71
  10     Datasheet: http://www.ti.com/product/LM71
  11   * National Semiconductor LM74
  12     Datasheet: http://www.ti.com/product/LM74
  13
  14 Author:
  15         Kaiwan N Billimoria <kaiwan@designergraphix.com>
  16
  17 Description
  18 -----------
  19
  20 This driver implements support for the National Semiconductor LM70
  21 temperature sensor.
  22
  23 The LM70 temperature sensor chip supports a single temperature sensor.
  24 It communicates with a host processor (or microcontroller) via an
  25 SPI/Microwire Bus interface.
  26
  27 Communication with the LM70 is simple: when the temperature is to be sensed,
  28 the driver accesses the LM70 using SPI communication: 16 SCLK cycles
  29 comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's
  30 complement digital temperature (sent via the SIO line), is available in the
  31 driver for interpretation. This driver makes use of the kernel's in-core
  32 SPI support.
  33
  34 As a real (in-tree) example of this "SPI protocol driver" interfacing
  35 with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c
  36 and its associated documentation.
  37
  38 The LM74 and TMP121/TMP123 are very similar; main difference is 13-bit
  39 temperature data (0.0625 degrees celsius resolution).
  40
  41 The LM71 is also very similar; main difference is 14-bit temperature
  42 data (0.03125 degrees celsius resolution).
  43
  44 Thanks to
  45 ---------
  46 Jean Delvare <khali@linux-fr.org> for mentoring the hwmon-side driver
  47 development.