Kernel driver ltc2990

Supported chips:



LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor. The chip’s inputs can measure 4 voltages, or two inputs together (1+2 and 3+4) can be combined to measure a differential voltage, which is typically used to measure current through a series resistor, or a temperature with an external diode.

Usage Notes

This driver does not probe for PMBus devices. You will have to instantiate devices explicitly.

Sysfs attributes


Voltage at Vcc pin in millivolt (range 2.5V to 5V)


Internal chip temperature in millidegrees Celsius

A subset of the following attributes are visible, depending on the measurement mode of the chip.


Voltage at V[1-4] pin in millivolt


External temperature sensor TR1 in millidegrees Celsius


External temperature sensor TR2 in millidegrees Celsius


Current in mA across V1-V2 assuming a 1mOhm sense resistor


Current in mA across V3-V4 assuming a 1mOhm sense resistor

The “curr*_input” measurements actually report the voltage drop across the input pins in microvolts. This is equivalent to the current through a 1mOhm sense resistor. Divide the reported value by the actual sense resistor value in mOhm to get the actual value.