I2C

i2c is the driver side of lm-sensors, now included with the 2.6 kernel. Here is the description from the kernel config:

I2C (pronounce: I-square-C) is a slow serial bus protocol used in many micro controller applications and developed by Philips. SMBus, or System Management Bus is a subset of the I2C protocol. More information is contained in the directory , especially in the file called "summary" there. Both I2C and SMBus are supported here. You will need this for hardware sensors support, and also for Video For Linux support. Specifically, if you want to use a BT848 based frame grabber/overlay boards under Linux, say Y here and also to "I2C bit-banging  interfaces", below. If you want I2C support, you should say Y here and also to the specific driver for your bus adapter(s) below. This I2C support can also be built as a module. If so, the module will be called i2c-core.

This method differs to ACPI's Thermal Zone.