1Kernel driver ltc4261
2=====================
3
4Supported chips:
5
6  * Linear Technology LTC4261
7
8    Prefix: 'ltc4261'
9
10    Addresses scanned: -
11
12    Datasheet:
13
14	http://cds.linear.com/docs/Datasheet/42612fb.pdf
15
16Author: Guenter Roeck <linux@roeck-us.net>
17
18
19Description
20-----------
21
22The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a board
23to be safely inserted and removed from a live backplane.
24
25
26Usage Notes
27-----------
28
29This driver does not probe for LTC4261 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 LTC4261 at address 0x10
34on I2C bus #1::
35
36	$ modprobe ltc4261
37	$ echo ltc4261 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
54The chip has two voltage sensors, but only one set of voltage alarm status bits.
55In many many designs, those alarms are associated with the ADIN2 sensor, due to
56the proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not available
57on all chip variants. To ensure that the alarm condition is reported to the user,
58report it with both voltage sensors.
59
60======================= =============================
61in1_input		ADIN2 voltage (mV)
62in1_min_alarm		ADIN/ADIN2 Undervoltage alarm
63in1_max_alarm		ADIN/ADIN2 Overvoltage alarm
64
65in2_input		ADIN voltage (mV)
66in2_min_alarm		ADIN/ADIN2 Undervoltage alarm
67in2_max_alarm		ADIN/ADIN2 Overvoltage alarm
68
69curr1_input		SENSE current (mA)
70curr1_alarm		SENSE overcurrent alarm
71======================= =============================
72