path: root/Documentation/hwmon/ltc4261
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authorFathi Boudra <fathi.boudra@linaro.org>2013-04-28 09:33:08 +0300
committerFathi Boudra <fathi.boudra@linaro.org>2013-04-28 09:33:08 +0300
commit3b4bd47f8f4ed3aaf7c81c9b5d2d37ad79fadf4a (patch)
treeb9996006addfd7ae70a39672b76843b49aebc189 /Documentation/hwmon/ltc4261
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+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>
+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