Kernel drivers ltc2947-i2c and ltc2947-spi

Supported chips:

Author: Nuno Sá <nuno.sa@analog.com>

Description

The LTC2947 is a high precision power and energy monitor that measures current, voltage, power, temperature, charge and energy. The device supports both SPI and I2C depending on the chip configuration. The device also measures accumulated quantities as energy. It has two banks of register’s to read/set energy related values. These banks can be configured independently to have setups like: energy1 accumulates always and enrgy2 only accumulates if current is positive (to check battery charging efficiency for example). The device also supports a GPIO pin that can be configured as output to control a fan as a function of measured temperature. Then, the GPIO becomes active as soon as a temperature reading is higher than a defined threshold. The temp2 channel is used to control this thresholds and to read the respective alarms.

Sysfs entries

The following attributes are supported. Limits are read-write, reset_history is write-only and all the other attributes are read-only.

in0_input

VP-VM voltage (mV).

in0_min

Undervoltage threshold

in0_max

Overvoltage threshold

in0_lowest

Lowest measured voltage

in0_highest

Highest measured voltage

in0_reset_history

Write 1 to reset in1 history

in0_min_alarm

Undervoltage alarm

in0_max_alarm

Overvoltage alarm

in0_label

Channel label (VP-VM)

in1_input

DVCC voltage (mV)

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 in2 history

in1_min_alarm

Undervoltage alarm

in1_max_alarm

Overvoltage alarm

in1_label

Channel label (DVCC)

curr1_input

IP-IM 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

curr1_label

Channel label (IP-IM)

power1_input

Power (in uW)

power1_min

Low power 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

power1_label

Channel label (Power)

temp1_input

Chip Temperature (in milliC)

temp1_min

Low temperature threshold

temp1_max

High temperature threshold

temp1_input_lowest

Historical minimum temperature use

temp1_input_highest

Historical maximum temperature use

temp1_reset_history

Write 1 to reset temp1 history

temp1_min_alarm

Low temperature alarm

temp1_max_alarm

High temperature alarm

temp1_label

Channel label (Ambient)

temp2_min

Low temperature threshold for fan control

temp2_max

High temperature threshold for fan control

temp2_min_alarm

Low temperature fan control alarm

temp2_max_alarm

High temperature fan control alarm

temp2_label

Channel label (TEMPFAN)

energy1_input

Measured energy over time (in microJoule)

energy2_input

Measured energy over time (in microJoule)