Kernel driver ltc2945

Supported chips:

Author: Guenter Roeck <>


The LTC2945 is a rail-to-rail system monitor that measures current, voltage, and power consumption.

Usage Notes

This driver does not probe for LTC2945 devices, since there is no register which can be safely used to identify the chip. You will have to instantiate the devices explicitly.

Example: the following will load the driver for an LTC2945 at address 0x10 on I2C bus #1:

$ modprobe ltc2945
$ echo ltc2945 0x10 > /sys/bus/i2c/devices/i2c-1/new_device

Sysfs entries

Voltage readings provided by this driver are reported as obtained from the ADC registers. If a set of voltage divider resistors is installed, calculate the real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the value of the divider resistor against the measured voltage and R2 is the value of the divider resistor against Ground.

Current reading provided by this driver is reported as obtained from the ADC Current Sense register. The reported value assumes that a 1 mOhm sense resistor is installed. If a different sense resistor is installed, calculate the real current by dividing the reported value by the sense resistor value in mOhm.

in1_input VIN voltage (mV). Voltage is measured either at SENSE+ or VDD pin depending on chip configuration.
in1_min Undervoltage threshold
in1_max Overvoltage threshold
in1_lowest Lowest measured voltage
in1_highest Highest measured voltage
in1_reset_history Write 1 to reset in1 history
in1_min_alarm Undervoltage alarm
in1_max_alarm Overvoltage alarm
in2_input ADIN voltage (mV)
in2_min Undervoltage threshold
in2_max Overvoltage threshold
in2_lowest Lowest measured voltage
in2_highest Highest measured voltage
in2_reset_history Write 1 to reset in2 history
in2_min_alarm Undervoltage alarm
in2_max_alarm Overvoltage alarm
curr1_input SENSE current (mA)
curr1_min Undercurrent threshold
curr1_max Overcurrent threshold
curr1_lowest Lowest measured current
curr1_highest Highest measured current
curr1_reset_history Write 1 to reset curr1 history
curr1_min_alarm Undercurrent alarm
curr1_max_alarm Overcurrent alarm
power1_input Power (in uW). Power is calculated based on SENSE+/VDD voltage or ADIN voltage depending on chip configuration.
power1_min Low lower threshold
power1_max High power threshold
power1_input_lowest Historical minimum power use
power1_input_highest Historical maximum power use
power1_reset_history Write 1 to reset power1 history
power1_min_alarm Low power alarm
power1_max_alarm High power alarm