xref: /OK3568_Linux_fs/kernel/Documentation/hwmon/ltc4260.rst (revision 4882a59341e53eb6f0b4789bf948001014eff981)
1*4882a593SmuzhiyunKernel driver ltc4260
2*4882a593Smuzhiyun=====================
3*4882a593Smuzhiyun
4*4882a593SmuzhiyunSupported chips:
5*4882a593Smuzhiyun
6*4882a593Smuzhiyun  * Linear Technology LTC4260
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8*4882a593Smuzhiyun    Prefix: 'ltc4260'
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun    Addresses scanned: -
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12*4882a593Smuzhiyun    Datasheet:
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14*4882a593Smuzhiyun	http://cds.linear.com/docs/en/datasheet/4260fc.pdf
15*4882a593Smuzhiyun
16*4882a593SmuzhiyunAuthor: Guenter Roeck <linux@roeck-us.net>
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18*4882a593Smuzhiyun
19*4882a593SmuzhiyunDescription
20*4882a593Smuzhiyun-----------
21*4882a593Smuzhiyun
22*4882a593SmuzhiyunThe LTC4260 Hot Swap controller allows a board to be safely inserted
23*4882a593Smuzhiyunand removed from a live backplane.
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun
26*4882a593SmuzhiyunUsage Notes
27*4882a593Smuzhiyun-----------
28*4882a593Smuzhiyun
29*4882a593SmuzhiyunThis driver does not probe for LTC4260 devices, since there is no register
30*4882a593Smuzhiyunwhich can be safely used to identify the chip. You will have to instantiate
31*4882a593Smuzhiyunthe devices explicitly.
32*4882a593Smuzhiyun
33*4882a593SmuzhiyunExample: the following will load the driver for an LTC4260 at address 0x10
34*4882a593Smuzhiyunon I2C bus #1::
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun	$ modprobe ltc4260
37*4882a593Smuzhiyun	$ echo ltc4260 0x10 > /sys/bus/i2c/devices/i2c-1/new_device
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39*4882a593Smuzhiyun
40*4882a593SmuzhiyunSysfs entries
41*4882a593Smuzhiyun-------------
42*4882a593Smuzhiyun
43*4882a593SmuzhiyunVoltage readings provided by this driver are reported as obtained from the ADC
44*4882a593Smuzhiyunregisters. If a set of voltage divider resistors is installed, calculate the
45*4882a593Smuzhiyunreal voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the
46*4882a593Smuzhiyunvalue of the divider resistor against the measured voltage and R2 is the value
47*4882a593Smuzhiyunof the divider resistor against Ground.
48*4882a593Smuzhiyun
49*4882a593SmuzhiyunCurrent reading provided by this driver is reported as obtained from the ADC
50*4882a593SmuzhiyunCurrent Sense register. The reported value assumes that a 1 mOhm sense resistor
51*4882a593Smuzhiyunis installed. If a different sense resistor is installed, calculate the real
52*4882a593Smuzhiyuncurrent by dividing the reported value by the sense resistor value in mOhm.
53*4882a593Smuzhiyun
54*4882a593Smuzhiyun======================= =======================
55*4882a593Smuzhiyunin1_input		SOURCE voltage (mV)
56*4882a593Smuzhiyunin1_min_alarm		Undervoltage alarm
57*4882a593Smuzhiyunin1_max_alarm		Overvoltage alarm
58*4882a593Smuzhiyun
59*4882a593Smuzhiyunin2_input		ADIN voltage (mV)
60*4882a593Smuzhiyunin2_alarm		Power bad alarm
61*4882a593Smuzhiyun
62*4882a593Smuzhiyuncurr1_input		SENSE current (mA)
63*4882a593Smuzhiyuncurr1_alarm		SENSE overcurrent alarm
64*4882a593Smuzhiyun======================= =======================
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