1*4882a593SmuzhiyunKernel driver lm70 2*4882a593Smuzhiyun================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunSupported chips: 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun * National Semiconductor LM70 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun Datasheet: http://www.national.com/pf/LM/LM70.html 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun * Texas Instruments TMP121/TMP123 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun Information: http://focus.ti.com/docs/prod/folders/print/tmp121.html 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun * Texas Instruments TMP122/TMP124 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun Information: https://www.ti.com/product/tmp122 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun * National Semiconductor LM71 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun Datasheet: https://www.ti.com/product/LM71 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun * National Semiconductor LM74 23*4882a593Smuzhiyun 24*4882a593Smuzhiyun Datasheet: https://www.ti.com/product/LM74 25*4882a593Smuzhiyun 26*4882a593Smuzhiyun 27*4882a593SmuzhiyunAuthor: 28*4882a593Smuzhiyun Kaiwan N Billimoria <kaiwan@designergraphix.com> 29*4882a593Smuzhiyun 30*4882a593SmuzhiyunDescription 31*4882a593Smuzhiyun----------- 32*4882a593Smuzhiyun 33*4882a593SmuzhiyunThis driver implements support for the National Semiconductor LM70 34*4882a593Smuzhiyuntemperature sensor. 35*4882a593Smuzhiyun 36*4882a593SmuzhiyunThe LM70 temperature sensor chip supports a single temperature sensor. 37*4882a593SmuzhiyunIt communicates with a host processor (or microcontroller) via an 38*4882a593SmuzhiyunSPI/Microwire Bus interface. 39*4882a593Smuzhiyun 40*4882a593SmuzhiyunCommunication with the LM70 is simple: when the temperature is to be sensed, 41*4882a593Smuzhiyunthe driver accesses the LM70 using SPI communication: 16 SCLK cycles 42*4882a593Smuzhiyuncomprise the MOSI/MISO loop. At the end of the transfer, the 11-bit 2's 43*4882a593Smuzhiyuncomplement digital temperature (sent via the SIO line), is available in the 44*4882a593Smuzhiyundriver for interpretation. This driver makes use of the kernel's in-core 45*4882a593SmuzhiyunSPI support. 46*4882a593Smuzhiyun 47*4882a593SmuzhiyunAs a real (in-tree) example of this "SPI protocol driver" interfacing 48*4882a593Smuzhiyunwith a "SPI master controller driver", see drivers/spi/spi_lm70llp.c 49*4882a593Smuzhiyunand its associated documentation. 50*4882a593Smuzhiyun 51*4882a593SmuzhiyunThe LM74 and TMP121/TMP122/TMP123/TMP124 are very similar; main difference is 52*4882a593Smuzhiyun13-bit temperature data (0.0625 degrees celsius resolution). 53*4882a593Smuzhiyun 54*4882a593SmuzhiyunThe TMP122/TMP124 also feature configurable temperature thresholds. 55*4882a593Smuzhiyun 56*4882a593SmuzhiyunThe LM71 is also very similar; main difference is 14-bit temperature 57*4882a593Smuzhiyundata (0.03125 degrees celsius resolution). 58*4882a593Smuzhiyun 59*4882a593SmuzhiyunThanks to 60*4882a593Smuzhiyun--------- 61*4882a593SmuzhiyunJean Delvare <jdelvare@suse.de> for mentoring the hwmon-side driver 62*4882a593Smuzhiyundevelopment. 63