1Kernel driver ltc4261 2===================== 3 4Supported chips: 5 * Linear Technology LTC4261 6 Prefix: 'ltc4261' 7 Addresses scanned: - 8 Datasheet: 9 http://cds.linear.com/docs/Datasheet/42612fb.pdf 10 11Author: Guenter Roeck <linux@roeck-us.net> 12 13 14Description 15----------- 16 17The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a board 18to be safely inserted and removed from a live backplane. 19 20 21Usage Notes 22----------- 23 24This driver does not probe for LTC4261 devices, since there is no register 25which can be safely used to identify the chip. You will have to instantiate 26the devices explicitly. 27 28Example: the following will load the driver for an LTC4261 at address 0x10 29on I2C bus #1: 30$ modprobe ltc4261 31$ echo ltc4261 0x10 > /sys/bus/i2c/devices/i2c-1/new_device 32 33 34Sysfs entries 35------------- 36 37Voltage readings provided by this driver are reported as obtained from the ADC 38registers. If a set of voltage divider resistors is installed, calculate the 39real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the 40value of the divider resistor against the measured voltage and R2 is the value 41of the divider resistor against Ground. 42 43Current reading provided by this driver is reported as obtained from the ADC 44Current Sense register. The reported value assumes that a 1 mOhm sense resistor 45is installed. If a different sense resistor is installed, calculate the real 46current by dividing the reported value by the sense resistor value in mOhm. 47 48The chip has two voltage sensors, but only one set of voltage alarm status bits. 49In many many designs, those alarms are associated with the ADIN2 sensor, due to 50the proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not available 51on all chip variants. To ensure that the alarm condition is reported to the user, 52report it with both voltage sensors. 53 54in1_input ADIN2 voltage (mV) 55in1_min_alarm ADIN/ADIN2 Undervoltage alarm 56in1_max_alarm ADIN/ADIN2 Overvoltage alarm 57 58in2_input ADIN voltage (mV) 59in2_min_alarm ADIN/ADIN2 Undervoltage alarm 60in2_max_alarm ADIN/ADIN2 Overvoltage alarm 61 62curr1_input SENSE current (mA) 63curr1_alarm SENSE overcurrent alarm 64