xref: /linux/Documentation/hwmon/ltc2945.rst (revision a4eb44a6435d6d8f9e642407a4a06f65eb90ca04)
1Kernel driver ltc2945
2=====================
3
4Supported chips:
5
6  * Linear Technology LTC2945
7
8    Prefix: 'ltc2945'
9
10    Addresses scanned: -
11
12    Datasheet:
13
14	https://www.analog.com/media/en/technical-documentation/data-sheets/2945fb.pdf
15
16Author: Guenter Roeck <linux@roeck-us.net>
17
18
19Description
20-----------
21
22The LTC2945  is a rail-to-rail system monitor that measures current, voltage,
23and power consumption.
24
25
26Usage Notes
27-----------
28
29This driver does not probe for LTC2945 devices, since there is no register
30which can be safely used to identify the chip. You will have to instantiate
31the devices explicitly.
32
33Example: the following will load the driver for an LTC2945 at address 0x10
34on I2C bus #1::
35
36	$ modprobe ltc2945
37	$ echo ltc2945 0x10 > /sys/bus/i2c/devices/i2c-1/new_device
38
39
40Sysfs entries
41-------------
42
43Voltage readings provided by this driver are reported as obtained from the ADC
44registers. If a set of voltage divider resistors is installed, calculate the
45real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the
46value of the divider resistor against the measured voltage and R2 is the value
47of the divider resistor against Ground.
48
49Current reading provided by this driver is reported as obtained from the ADC
50Current Sense register. The reported value assumes that a 1 mOhm sense resistor
51is installed. If a different sense resistor is installed, calculate the real
52current by dividing the reported value by the sense resistor value in mOhm.
53
54======================= ========================================================
55in1_input		VIN voltage (mV). Voltage is measured either at
56			SENSE+ or VDD pin depending on chip configuration.
57in1_min			Undervoltage threshold
58in1_max			Overvoltage threshold
59in1_lowest		Lowest measured voltage
60in1_highest		Highest measured voltage
61in1_reset_history	Write 1 to reset in1 history
62in1_min_alarm		Undervoltage alarm
63in1_max_alarm		Overvoltage alarm
64
65in2_input		ADIN voltage (mV)
66in2_min			Undervoltage threshold
67in2_max			Overvoltage threshold
68in2_lowest		Lowest measured voltage
69in2_highest		Highest measured voltage
70in2_reset_history	Write 1 to reset in2 history
71in2_min_alarm		Undervoltage alarm
72in2_max_alarm		Overvoltage alarm
73
74curr1_input		SENSE current (mA)
75curr1_min		Undercurrent threshold
76curr1_max		Overcurrent threshold
77curr1_lowest		Lowest measured current
78curr1_highest		Highest measured current
79curr1_reset_history	Write 1 to reset curr1 history
80curr1_min_alarm		Undercurrent alarm
81curr1_max_alarm		Overcurrent alarm
82
83power1_input		Power (in uW). Power is calculated based on SENSE+/VDD
84			voltage or ADIN voltage depending on chip configuration.
85power1_min		Low lower threshold
86power1_max		High power threshold
87power1_input_lowest	Historical minimum power use
88power1_input_highest	Historical maximum power use
89power1_reset_history	Write 1 to reset power1 history
90power1_min_alarm	Low power alarm
91power1_max_alarm	High power alarm
92======================= ========================================================
93