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