lm70.rst (2012B)
1Kernel driver lm70 2================== 3 4Supported chips: 5 6 * National Semiconductor LM70 7 8 Datasheet: http://www.national.com/pf/LM/LM70.html 9 10 * Texas Instruments TMP121/TMP123 11 12 Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html 13 14 * Texas Instruments TMP122/TMP124 15 16 Information: https://www.ti.com/product/tmp122 17 18 * Texas Instruments TMP125 19 20 Information: https://www.ti.com/product/tmp125 21 22 * National Semiconductor LM71 23 24 Datasheet: https://www.ti.com/product/LM71 25 26 * National Semiconductor LM74 27 28 Datasheet: https://www.ti.com/product/LM74 29 30 31Author: 32 Kaiwan N Billimoria <kaiwan@designergraphix.com> 33 34Description 35----------- 36 37This driver implements support for the National Semiconductor LM70 38temperature sensor. 39 40The LM70 temperature sensor chip supports a single temperature sensor. 41It communicates with a host processor (or microcontroller) via an 42SPI/Microwire Bus interface. 43 44Communication with the LM70 is simple: when the temperature is to be sensed, 45the driver accesses the LM70 using SPI communication: 16 SCLK cycles 46comprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's 47complement digital temperature (sent via the SIO line), is available in the 48driver for interpretation. This driver makes use of the kernel's in-core 49SPI support. 50 51As a real (in-tree) example of this "SPI protocol driver" interfacing 52with a "SPI master controller driver", see drivers/spi/spi_lm70llp.c 53and its associated documentation. 54 55The LM74 and TMP121/TMP122/TMP123/TMP124 are very similar; main difference is 5613-bit temperature data (0.0625 degrees celsius resolution). 57 58The TMP122/TMP124 also feature configurable temperature thresholds. 59 60The TMP125 is less accurate and provides 10-bit temperature data 61with 0.25 degrees Celsius resolution. 62 63The LM71 is also very similar; main difference is 14-bit temperature 64data (0.03125 degrees celsius resolution). 65 66Thanks to 67--------- 68Jean Delvare <jdelvare@suse.de> for mentoring the hwmon-side driver 69development.