64 lines
2.1 KiB
Plaintext
64 lines
2.1 KiB
Plaintext
Kernel driver ltc4261
|
|
=====================
|
|
|
|
Supported chips:
|
|
* Linear Technology LTC4261
|
|
Prefix: 'ltc4261'
|
|
Addresses scanned: -
|
|
Datasheet:
|
|
http://cds.linear.com/docs/Datasheet/42612fb.pdf
|
|
|
|
Author: Guenter Roeck <linux@roeck-us.net>
|
|
|
|
|
|
Description
|
|
-----------
|
|
|
|
The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a board
|
|
to be safely inserted and removed from a live backplane.
|
|
|
|
|
|
Usage Notes
|
|
-----------
|
|
|
|
This driver does not probe for LTC4261 devices, since there is no register
|
|
which can be safely used to identify the chip. You will have to instantiate
|
|
the devices explicitly.
|
|
|
|
Example: the following will load the driver for an LTC4261 at address 0x10
|
|
on I2C bus #1:
|
|
$ modprobe ltc4261
|
|
$ echo ltc4261 0x10 > /sys/bus/i2c/devices/i2c-1/new_device
|
|
|
|
|
|
Sysfs entries
|
|
-------------
|
|
|
|
Voltage readings provided by this driver are reported as obtained from the ADC
|
|
registers. If a set of voltage divider resistors is installed, calculate the
|
|
real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the
|
|
value of the divider resistor against the measured voltage and R2 is the value
|
|
of the divider resistor against Ground.
|
|
|
|
Current reading provided by this driver is reported as obtained from the ADC
|
|
Current Sense register. The reported value assumes that a 1 mOhm sense resistor
|
|
is installed. If a different sense resistor is installed, calculate the real
|
|
current by dividing the reported value by the sense resistor value in mOhm.
|
|
|
|
The chip has two voltage sensors, but only one set of voltage alarm status bits.
|
|
In many many designs, those alarms are associated with the ADIN2 sensor, due to
|
|
the proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not available
|
|
on all chip variants. To ensure that the alarm condition is reported to the user,
|
|
report it with both voltage sensors.
|
|
|
|
in1_input ADIN2 voltage (mV)
|
|
in1_min_alarm ADIN/ADIN2 Undervoltage alarm
|
|
in1_max_alarm ADIN/ADIN2 Overvoltage alarm
|
|
|
|
in2_input ADIN voltage (mV)
|
|
in2_min_alarm ADIN/ADIN2 Undervoltage alarm
|
|
in2_max_alarm ADIN/ADIN2 Overvoltage alarm
|
|
|
|
curr1_input SENSE current (mA)
|
|
curr1_alarm SENSE overcurrent alarm
|