| xj | b04a402 | 2021-11-25 15:01:52 +0800 | [diff] [blame] | 1 | Kernel driver ltc2990 |
| 2 | ===================== |
| 3 | |
| 4 | Supported chips: |
| 5 | * Linear Technology LTC2990 |
| 6 | Prefix: 'ltc2990' |
| 7 | Addresses scanned: - |
| 8 | Datasheet: http://www.linear.com/product/ltc2990 |
| 9 | |
| 10 | Author: Mike Looijmans <mike.looijmans@topic.nl> |
| 11 | Tom Levens <tom.levens@cern.ch> |
| 12 | |
| 13 | |
| 14 | Description |
| 15 | ----------- |
| 16 | |
| 17 | LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor. |
| 18 | The chip's inputs can measure 4 voltages, or two inputs together (1+2 and 3+4) |
| 19 | can be combined to measure a differential voltage, which is typically used to |
| 20 | measure current through a series resistor, or a temperature with an external |
| 21 | diode. |
| 22 | |
| 23 | |
| 24 | Usage Notes |
| 25 | ----------- |
| 26 | |
| 27 | This driver does not probe for PMBus devices. You will have to instantiate |
| 28 | devices explicitly. |
| 29 | |
| 30 | |
| 31 | Sysfs attributes |
| 32 | ---------------- |
| 33 | |
| 34 | in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V) |
| 35 | temp1_input Internal chip temperature in millidegrees Celcius |
| 36 | |
| 37 | A subset of the following attributes are visible, depending on the measurement |
| 38 | mode of the chip. |
| 39 | |
| 40 | in[1-4]_input Voltage at V[1-4] pin in millivolt |
| 41 | temp2_input External temperature sensor TR1 in millidegrees Celcius |
| 42 | temp3_input External temperature sensor TR2 in millidegrees Celcius |
| 43 | curr1_input Current in mA across V1-V2 assuming a 1mOhm sense resistor |
| 44 | curr2_input Current in mA across V3-V4 assuming a 1mOhm sense resistor |
| 45 | |
| 46 | The "curr*_input" measurements actually report the voltage drop across the |
| 47 | input pins in microvolts. This is equivalent to the current through a 1mOhm |
| 48 | sense resistor. Divide the reported value by the actual sense resistor value |
| 49 | in mOhm to get the actual value. |