Description¶

The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a boardto be safely inserted and removed from a live backplane.

Usage Notes¶

This driver does not probe for LTC4261 devices, since there is no registerwhich can be safely used to identify the chip. You will have to instantiatethe devices explicitly.

Example: the following will load the driver for an LTC4261 at address 0x10on 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 ADCregisters. If a set of voltage divider resistors is installed, calculate thereal voltage by multiplying the reported value with (R1+R2)/R2, where R1 is thevalue of the divider resistor against the measured voltage and R2 is the valueof the divider resistor against Ground.

Current reading provided by this driver is reported as obtained from the ADCCurrent Sense register. The reported value assumes that a 1 mOhm sense resistoris installed. If a different sense resistor is installed, calculate the realcurrent 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 tothe proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not availableon all chip variants. To ensure that the alarm condition is reported to the user,report it with both voltage sensors.