1 Kernel driver ltc2990 1 Kernel driver ltc2990
2 ===================== 2 =====================
3 3
4 4
5 Supported chips: 5 Supported chips:
6 6
7 * Linear Technology LTC2990 7 * Linear Technology LTC2990
8 8
9 Prefix: 'ltc2990' 9 Prefix: 'ltc2990'
10 10
11 Addresses scanned: - 11 Addresses scanned: -
12 12
13 Datasheet: http://www.linear.com/product/l 13 Datasheet: http://www.linear.com/product/ltc2990
14 14
15 15
16 16
17 Author: 17 Author:
18 18
19 - Mike Looijmans <mike.looijmans@topic. 19 - Mike Looijmans <mike.looijmans@topic.nl>
20 - Tom Levens <tom.levens@cern.ch> 20 - Tom Levens <tom.levens@cern.ch>
21 21
22 22
23 Description 23 Description
24 ----------- 24 -----------
25 25
26 LTC2990 is a Quad I2C Voltage, Current and Tem 26 LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor.
27 The chip's inputs can measure 4 voltages, or t 27 The chip's inputs can measure 4 voltages, or two inputs together (1+2 and 3+4)
28 can be combined to measure a differential volt 28 can be combined to measure a differential voltage, which is typically used to
29 measure current through a series resistor, or 29 measure current through a series resistor, or a temperature with an external
30 diode. 30 diode.
31 31
32 32
33 Usage Notes 33 Usage Notes
34 ----------- 34 -----------
35 35
36 This driver does not probe for PMBus devices. 36 This driver does not probe for PMBus devices. You will have to instantiate
37 devices explicitly. 37 devices explicitly.
38 38
39 39
40 Sysfs attributes 40 Sysfs attributes
41 ---------------- 41 ----------------
42 42
43 ============= ================================ 43 ============= ==================================================
44 in0_input Voltage at Vcc pin in millivolt 44 in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
45 temp1_input Internal chip temperature in mil 45 temp1_input Internal chip temperature in millidegrees Celsius
46 ============= ================================ 46 ============= ==================================================
47 47
48 A subset of the following attributes are visib 48 A subset of the following attributes are visible, depending on the measurement
49 mode of the chip. 49 mode of the chip.
50 50
51 ============= ================================ 51 ============= ==========================================================
52 in[1-4]_input Voltage at V[1-4] pin in millivo 52 in[1-4]_input Voltage at V[1-4] pin in millivolt
53 temp2_input External temperature sensor TR1 53 temp2_input External temperature sensor TR1 in millidegrees Celsius
54 temp3_input External temperature sensor TR2 54 temp3_input External temperature sensor TR2 in millidegrees Celsius
55 curr1_input Current in mA across V1-V2 assum 55 curr1_input Current in mA across V1-V2 assuming a 1mOhm sense resistor
56 curr2_input Current in mA across V3-V4 assum 56 curr2_input Current in mA across V3-V4 assuming a 1mOhm sense resistor
57 ============= ================================ 57 ============= ==========================================================
58 58
59 The "curr*_input" measurements actually report 59 The "curr*_input" measurements actually report the voltage drop across the
60 input pins in microvolts. This is equivalent t 60 input pins in microvolts. This is equivalent to the current through a 1mOhm
61 sense resistor. Divide the reported value by t 61 sense resistor. Divide the reported value by the actual sense resistor value
62 in mOhm to get the actual value. 62 in mOhm to get the actual value.
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