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hwmon: Add LTC2990 sensor driver This adds support for the Linear Technology LTC2990 I2C System Monitor. The LTC2990 supports a combination of voltage, current and temperature monitoring. This driver currently only supports reading two currents by measuring two differential voltages across series resistors, in addition to the Vcc supply voltage and internal temperature. This is sufficient to support the Topic Miami SOM which uses this chip to monitor the currents flowing into the FPGA and the CPU parts. Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-01-15 17:54:59 +08:00
Kernel driver ltc2990
=====================
Supported chips:
* Linear Technology LTC2990
Prefix: 'ltc2990'
Addresses scanned: -
Datasheet: http://www.linear.com/product/ltc2990
Author: Mike Looijmans <mike.looijmans@topic.nl>
hwmon: (ltc2990) support all measurement modes Updated version of the ltc2990 driver which supports all measurement modes (current, voltage, temperature) available in the chip. If devicetree is used, the mode must be specified with the property "lltc,meas-mode". The format and possible values of the property are described in the binding. If devicetree is not used, the mode of the chip will not be configured. Unless the chip is configured by another source, only the internal temperature and supply voltage will be measured. Signed-off-by: Tom Levens <tom.levens@cern.ch> Tested-By: mike.looijmans@topic.nl [groeck: Fixed compiler warning] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-07-03 12:29:00 +08:00
Tom Levens <tom.levens@cern.ch>
hwmon: Add LTC2990 sensor driver This adds support for the Linear Technology LTC2990 I2C System Monitor. The LTC2990 supports a combination of voltage, current and temperature monitoring. This driver currently only supports reading two currents by measuring two differential voltages across series resistors, in addition to the Vcc supply voltage and internal temperature. This is sufficient to support the Topic Miami SOM which uses this chip to monitor the currents flowing into the FPGA and the CPU parts. Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-01-15 17:54:59 +08:00
Description
-----------
LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor.
The chip's inputs can measure 4 voltages, or two inputs together (1+2 and 3+4)
can be combined to measure a differential voltage, which is typically used to
hwmon: (ltc2990) support all measurement modes Updated version of the ltc2990 driver which supports all measurement modes (current, voltage, temperature) available in the chip. If devicetree is used, the mode must be specified with the property "lltc,meas-mode". The format and possible values of the property are described in the binding. If devicetree is not used, the mode of the chip will not be configured. Unless the chip is configured by another source, only the internal temperature and supply voltage will be measured. Signed-off-by: Tom Levens <tom.levens@cern.ch> Tested-By: mike.looijmans@topic.nl [groeck: Fixed compiler warning] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-07-03 12:29:00 +08:00
measure current through a series resistor, or a temperature with an external
diode.
hwmon: Add LTC2990 sensor driver This adds support for the Linear Technology LTC2990 I2C System Monitor. The LTC2990 supports a combination of voltage, current and temperature monitoring. This driver currently only supports reading two currents by measuring two differential voltages across series resistors, in addition to the Vcc supply voltage and internal temperature. This is sufficient to support the Topic Miami SOM which uses this chip to monitor the currents flowing into the FPGA and the CPU parts. Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-01-15 17:54:59 +08:00
Usage Notes
-----------
This driver does not probe for PMBus devices. You will have to instantiate
devices explicitly.
Sysfs attributes
----------------
hwmon: (ltc2990) support all measurement modes Updated version of the ltc2990 driver which supports all measurement modes (current, voltage, temperature) available in the chip. If devicetree is used, the mode must be specified with the property "lltc,meas-mode". The format and possible values of the property are described in the binding. If devicetree is not used, the mode of the chip will not be configured. Unless the chip is configured by another source, only the internal temperature and supply voltage will be measured. Signed-off-by: Tom Levens <tom.levens@cern.ch> Tested-By: mike.looijmans@topic.nl [groeck: Fixed compiler warning] Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2017-07-03 12:29:00 +08:00
in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
temp1_input Internal chip temperature in millidegrees Celcius
A subset of the following attributes are visible, depending on the measurement
mode of the chip.
in[1-4]_input Voltage at V[1-4] pin in millivolt
temp2_input External temperature sensor TR1 in millidegrees Celcius
temp3_input External temperature sensor TR2 in millidegrees Celcius
curr1_input Current in mA across V1-V2 assuming a 1mOhm sense resistor
curr2_input Current in mA across V3-V4 assuming a 1mOhm sense resistor
hwmon: Add LTC2990 sensor driver This adds support for the Linear Technology LTC2990 I2C System Monitor. The LTC2990 supports a combination of voltage, current and temperature monitoring. This driver currently only supports reading two currents by measuring two differential voltages across series resistors, in addition to the Vcc supply voltage and internal temperature. This is sufficient to support the Topic Miami SOM which uses this chip to monitor the currents flowing into the FPGA and the CPU parts. Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
2016-01-15 17:54:59 +08:00
The "curr*_input" measurements actually report the voltage drop across the
input pins in microvolts. This is equivalent to the current through a 1mOhm
sense resistor. Divide the reported value by the actual sense resistor value
in mOhm to get the actual value.