Kernel drivers ltc2947-i2c and ltc2947-spi¶
Supported chips:
Analog Devices LTC2947
Prefix: ‘ltc2947’
Addresses scanned: -
Datasheet:
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) |