0001 Kernel driver ltc4261
0002 =====================
0003
0004 Supported chips:
0005
0006 * Linear Technology LTC4261
0007
0008 Prefix: 'ltc4261'
0009
0010 Addresses scanned: -
0011
0012 Datasheet:
0013
0014 http://cds.linear.com/docs/Datasheet/42612fb.pdf
0015
0016 Author: Guenter Roeck <linux@roeck-us.net>
0017
0018
0019 Description
0020 -----------
0021
0022 The LTC4261/LTC4261-2 negative voltage Hot Swap controllers allow a board
0023 to be safely inserted and removed from a live backplane.
0024
0025
0026 Usage Notes
0027 -----------
0028
0029 This driver does not probe for LTC4261 devices, since there is no register
0030 which can be safely used to identify the chip. You will have to instantiate
0031 the devices explicitly.
0032
0033 Example: the following will load the driver for an LTC4261 at address 0x10
0034 on I2C bus #1::
0035
0036 $ modprobe ltc4261
0037 $ echo ltc4261 0x10 > /sys/bus/i2c/devices/i2c-1/new_device
0038
0039
0040 Sysfs entries
0041 -------------
0042
0043 Voltage readings provided by this driver are reported as obtained from the ADC
0044 registers. If a set of voltage divider resistors is installed, calculate the
0045 real voltage by multiplying the reported value with (R1+R2)/R2, where R1 is the
0046 value of the divider resistor against the measured voltage and R2 is the value
0047 of the divider resistor against Ground.
0048
0049 Current reading provided by this driver is reported as obtained from the ADC
0050 Current Sense register. The reported value assumes that a 1 mOhm sense resistor
0051 is installed. If a different sense resistor is installed, calculate the real
0052 current by dividing the reported value by the sense resistor value in mOhm.
0053
0054 The chip has two voltage sensors, but only one set of voltage alarm status bits.
0055 In many many designs, those alarms are associated with the ADIN2 sensor, due to
0056 the proximity of the ADIN2 pin to the OV pin. ADIN2 is, however, not available
0057 on all chip variants. To ensure that the alarm condition is reported to the user,
0058 report it with both voltage sensors.
0059
0060 ======================= =============================
0061 in1_input ADIN2 voltage (mV)
0062 in1_min_alarm ADIN/ADIN2 Undervoltage alarm
0063 in1_max_alarm ADIN/ADIN2 Overvoltage alarm
0064
0065 in2_input ADIN voltage (mV)
0066 in2_min_alarm ADIN/ADIN2 Undervoltage alarm
0067 in2_max_alarm ADIN/ADIN2 Overvoltage alarm
0068
0069 curr1_input SENSE current (mA)
0070 curr1_alarm SENSE overcurrent alarm
0071 ======================= =============================
