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1Kernel driver lm832==================3 4Supported chips:5 6 * National Semiconductor LM837 8 Prefix: 'lm83'9 10 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e11 12 Datasheet: Publicly available at the National Semiconductor website13 14 http://www.national.com/pf/LM/LM83.html15 16 * National Semiconductor LM8217 18 Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e19 20 Datasheet: Publicly available at the National Semiconductor website21 22 http://www.national.com/pf/LM/LM82.html23 24Author: Jean Delvare <jdelvare@suse.de>25 26Description27-----------28 29The LM83 is a digital temperature sensor. It senses its own temperature as30well as the temperature of up to three external diodes. The LM82 is31a stripped down version of the LM83 that only supports one external diode.32Both are compatible with many other devices such as the LM84 and all33other ADM1021 clones. The main difference between the LM83 and the LM8434in that the later can only sense the temperature of one external diode.35 36Using the adm1021 driver for a LM83 should work, but only two temperatures37will be reported instead of four.38 39The LM83 is only found on a handful of motherboards. Both a confirmed40list and an unconfirmed list follow. If you can confirm or infirm the41fact that any of these motherboards do actually have an LM83, please42contact us. Note that the LM90 can easily be misdetected as a LM83.43 44Confirmed motherboards:45 === =====46 SBS P01447 SBS PSL0948 === =====49 50Unconfirmed motherboards:51 =========== ==========52 Gigabyte GA-8IK110053 Iwill MPX254 Soltek SL-75DRV555 =========== ==========56 57The LM82 is confirmed to have been found on most AMD Geode reference58designs and test platforms.59 60The driver has been successfully tested by Magnus Forsström, who I'd61like to thank here. More testers will be of course welcome.62 63The fact that the LM83 is only scarcely used can be easily explained.64Most motherboards come with more than just temperature sensors for65health monitoring. They also have voltage and fan rotation speed66sensors. This means that temperature-only chips are usually used as67secondary chips coupled with another chip such as an IT8705F or similar68chip, which provides more features. Since systems usually need three69temperature sensors (motherboard, processor, power supply) and primary70chips provide some temperature sensors, the secondary chip, if needed,71won't have to handle more than two temperatures. Thus, ADM1021 clones72are sufficient, and there is no need for a four temperatures sensor73chip such as the LM83. The only case where using an LM83 would make74sense is on SMP systems, such as the above-mentioned Iwill MPX2,75because you want an additional temperature sensor for each additional76CPU.77 78On the SBS P014, this is different, since the LM83 is the only hardware79monitoring chipset. One temperature sensor is used for the motherboard80(actually measuring the LM83's own temperature), one is used for the81CPU. The two other sensors must be used to measure the temperature of82two other points of the motherboard. We suspect these points to be the83north and south bridges, but this couldn't be confirmed.84 85All temperature values are given in degrees Celsius. Local temperature86is given within a range of 0 to +85 degrees. Remote temperatures are87given within a range of 0 to +125 degrees. Resolution is 1.0 degree,88accuracy is guaranteed to 3.0 degrees (see the datasheet for more89details).90 91Each sensor has its own high limit, but the critical limit is common to92all four sensors. There is no hysteresis mechanism as found on most93recent temperature sensors.94 95The lm83 driver will not update its values more frequently than every96other second; reading them more often will do no harm, but will return97'old' values.98