1*4882a593SmuzhiyunKernel driver lm83 2*4882a593Smuzhiyun================== 3*4882a593Smuzhiyun 4*4882a593SmuzhiyunSupported chips: 5*4882a593Smuzhiyun 6*4882a593Smuzhiyun * National Semiconductor LM83 7*4882a593Smuzhiyun 8*4882a593Smuzhiyun Prefix: 'lm83' 9*4882a593Smuzhiyun 10*4882a593Smuzhiyun Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e 11*4882a593Smuzhiyun 12*4882a593Smuzhiyun Datasheet: Publicly available at the National Semiconductor website 13*4882a593Smuzhiyun 14*4882a593Smuzhiyun http://www.national.com/pf/LM/LM83.html 15*4882a593Smuzhiyun 16*4882a593Smuzhiyun * National Semiconductor LM82 17*4882a593Smuzhiyun 18*4882a593Smuzhiyun Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e 19*4882a593Smuzhiyun 20*4882a593Smuzhiyun Datasheet: Publicly available at the National Semiconductor website 21*4882a593Smuzhiyun 22*4882a593Smuzhiyun http://www.national.com/pf/LM/LM82.html 23*4882a593Smuzhiyun 24*4882a593SmuzhiyunAuthor: Jean Delvare <jdelvare@suse.de> 25*4882a593Smuzhiyun 26*4882a593SmuzhiyunDescription 27*4882a593Smuzhiyun----------- 28*4882a593Smuzhiyun 29*4882a593SmuzhiyunThe LM83 is a digital temperature sensor. It senses its own temperature as 30*4882a593Smuzhiyunwell as the temperature of up to three external diodes. The LM82 is 31*4882a593Smuzhiyuna stripped down version of the LM83 that only supports one external diode. 32*4882a593SmuzhiyunBoth are compatible with many other devices such as the LM84 and all 33*4882a593Smuzhiyunother ADM1021 clones. The main difference between the LM83 and the LM84 34*4882a593Smuzhiyunin that the later can only sense the temperature of one external diode. 35*4882a593Smuzhiyun 36*4882a593SmuzhiyunUsing the adm1021 driver for a LM83 should work, but only two temperatures 37*4882a593Smuzhiyunwill be reported instead of four. 38*4882a593Smuzhiyun 39*4882a593SmuzhiyunThe LM83 is only found on a handful of motherboards. Both a confirmed 40*4882a593Smuzhiyunlist and an unconfirmed list follow. If you can confirm or infirm the 41*4882a593Smuzhiyunfact that any of these motherboards do actually have an LM83, please 42*4882a593Smuzhiyuncontact us. Note that the LM90 can easily be misdetected as a LM83. 43*4882a593Smuzhiyun 44*4882a593SmuzhiyunConfirmed motherboards: 45*4882a593Smuzhiyun === ===== 46*4882a593Smuzhiyun SBS P014 47*4882a593Smuzhiyun SBS PSL09 48*4882a593Smuzhiyun === ===== 49*4882a593Smuzhiyun 50*4882a593SmuzhiyunUnconfirmed motherboards: 51*4882a593Smuzhiyun =========== ========== 52*4882a593Smuzhiyun Gigabyte GA-8IK1100 53*4882a593Smuzhiyun Iwill MPX2 54*4882a593Smuzhiyun Soltek SL-75DRV5 55*4882a593Smuzhiyun =========== ========== 56*4882a593Smuzhiyun 57*4882a593SmuzhiyunThe LM82 is confirmed to have been found on most AMD Geode reference 58*4882a593Smuzhiyundesigns and test platforms. 59*4882a593Smuzhiyun 60*4882a593SmuzhiyunThe driver has been successfully tested by Magnus Forsström, who I'd 61*4882a593Smuzhiyunlike to thank here. More testers will be of course welcome. 62*4882a593Smuzhiyun 63*4882a593SmuzhiyunThe fact that the LM83 is only scarcely used can be easily explained. 64*4882a593SmuzhiyunMost motherboards come with more than just temperature sensors for 65*4882a593Smuzhiyunhealth monitoring. They also have voltage and fan rotation speed 66*4882a593Smuzhiyunsensors. This means that temperature-only chips are usually used as 67*4882a593Smuzhiyunsecondary chips coupled with another chip such as an IT8705F or similar 68*4882a593Smuzhiyunchip, which provides more features. Since systems usually need three 69*4882a593Smuzhiyuntemperature sensors (motherboard, processor, power supply) and primary 70*4882a593Smuzhiyunchips provide some temperature sensors, the secondary chip, if needed, 71*4882a593Smuzhiyunwon't have to handle more than two temperatures. Thus, ADM1021 clones 72*4882a593Smuzhiyunare sufficient, and there is no need for a four temperatures sensor 73*4882a593Smuzhiyunchip such as the LM83. The only case where using an LM83 would make 74*4882a593Smuzhiyunsense is on SMP systems, such as the above-mentioned Iwill MPX2, 75*4882a593Smuzhiyunbecause you want an additional temperature sensor for each additional 76*4882a593SmuzhiyunCPU. 77*4882a593Smuzhiyun 78*4882a593SmuzhiyunOn the SBS P014, this is different, since the LM83 is the only hardware 79*4882a593Smuzhiyunmonitoring chipset. One temperature sensor is used for the motherboard 80*4882a593Smuzhiyun(actually measuring the LM83's own temperature), one is used for the 81*4882a593SmuzhiyunCPU. The two other sensors must be used to measure the temperature of 82*4882a593Smuzhiyuntwo other points of the motherboard. We suspect these points to be the 83*4882a593Smuzhiyunnorth and south bridges, but this couldn't be confirmed. 84*4882a593Smuzhiyun 85*4882a593SmuzhiyunAll temperature values are given in degrees Celsius. Local temperature 86*4882a593Smuzhiyunis given within a range of 0 to +85 degrees. Remote temperatures are 87*4882a593Smuzhiyungiven within a range of 0 to +125 degrees. Resolution is 1.0 degree, 88*4882a593Smuzhiyunaccuracy is guaranteed to 3.0 degrees (see the datasheet for more 89*4882a593Smuzhiyundetails). 90*4882a593Smuzhiyun 91*4882a593SmuzhiyunEach sensor has its own high limit, but the critical limit is common to 92*4882a593Smuzhiyunall four sensors. There is no hysteresis mechanism as found on most 93*4882a593Smuzhiyunrecent temperature sensors. 94*4882a593Smuzhiyun 95*4882a593SmuzhiyunThe lm83 driver will not update its values more frequently than every 96*4882a593Smuzhiyunother second; reading them more often will do no harm, but will return 97*4882a593Smuzhiyun'old' values. 98