xref: /linux/Documentation/hwmon/ltc2947.rst (revision c95baf12f5077419db01313ab61c2aac007d40cd)
1Kernel drivers ltc2947-i2c and ltc2947-spi
2==========================================
3
4Supported chips:
5
6  * Analog Devices LTC2947
7
8    Prefix: 'ltc2947'
9
10    Addresses scanned: -
11
12    Datasheet:
13
14        https://www.analog.com/media/en/technical-documentation/data-sheets/LTC2947.pdf
15
16Author: Nuno Sá <nuno.sa@analog.com>
17
18Description
19___________
20
21The LTC2947 is a high precision power and energy monitor that measures current,
22voltage, power, temperature, charge and energy. The device supports both SPI
23and I2C depending on the chip configuration.
24The device also measures accumulated quantities as energy. It has two banks of
25register's to read/set energy related values. These banks can be configured
26independently to have setups like: energy1 accumulates always and enrgy2 only
27accumulates if current is positive (to check battery charging efficiency for
28example). The device also supports a GPIO pin that can be configured as output
29to control a fan as a function of measured temperature. Then, the GPIO becomes
30active as soon as a temperature reading is higher than a defined threshold. The
31temp2 channel is used to control this thresholds and to read the respective
32alarms.
33
34Sysfs entries
35_____________
36
37The following attributes are supported. Limits are read-write, reset_history
38is write-only and all the other attributes are read-only.
39
40======================= ==========================================
41in0_input		VP-VM voltage (mV).
42in0_min			Undervoltage threshold
43in0_max			Overvoltage threshold
44in0_lowest		Lowest measured voltage
45in0_highest		Highest measured voltage
46in0_reset_history	Write 1 to reset in1 history
47in0_min_alarm		Undervoltage alarm
48in0_max_alarm		Overvoltage alarm
49in0_label		Channel label (VP-VM)
50
51in1_input		DVCC voltage (mV)
52in1_min			Undervoltage threshold
53in1_max			Overvoltage threshold
54in1_lowest		Lowest measured voltage
55in1_highest		Highest measured voltage
56in1_reset_history	Write 1 to reset in2 history
57in1_min_alarm		Undervoltage alarm
58in1_max_alarm		Overvoltage alarm
59in1_label		Channel label (DVCC)
60
61curr1_input		IP-IM Sense current (mA)
62curr1_min		Undercurrent threshold
63curr1_max		Overcurrent threshold
64curr1_lowest		Lowest measured current
65curr1_highest		Highest measured current
66curr1_reset_history	Write 1 to reset curr1 history
67curr1_min_alarm		Undercurrent alarm
68curr1_max_alarm		Overcurrent alarm
69curr1_label		Channel label (IP-IM)
70
71power1_input		Power (in uW)
72power1_min		Low power threshold
73power1_max		High power threshold
74power1_input_lowest	Historical minimum power use
75power1_input_highest	Historical maximum power use
76power1_reset_history	Write 1 to reset power1 history
77power1_min_alarm	Low power alarm
78power1_max_alarm	High power alarm
79power1_label		Channel label (Power)
80
81temp1_input		Chip Temperature (in milliC)
82temp1_min		Low temperature threshold
83temp1_max		High temperature threshold
84temp1_input_lowest	Historical minimum temperature use
85temp1_input_highest	Historical maximum temperature use
86temp1_reset_history	Write 1 to reset temp1 history
87temp1_min_alarm		Low temperature alarm
88temp1_max_alarm		High temperature alarm
89temp1_label		Channel label (Ambient)
90
91temp2_min		Low temperature threshold for fan control
92temp2_max		High temperature threshold for fan control
93temp2_min_alarm		Low temperature fan control alarm
94temp2_max_alarm		High temperature fan control alarm
95temp2_label		Channel label (TEMPFAN)
96
97energy1_input		Measured energy over time (in microJoule)
98
99energy2_input		Measured energy over time (in microJoule)
100======================= ==========================================
101