summaryrefslogtreecommitdiff
path: root/Documentation/hwmon
diff options
context:
space:
mode:
authorTom Levens <tom.levens@cern.ch>2017-07-03 07:29:00 +0300
committerGuenter Roeck <linux@roeck-us.net>2018-05-21 17:52:01 +0300
commit5d9ca430ea3ae87e41a69333ca30533e9cdc17cf (patch)
tree475cd040bf02cbbabbee202b8a598905f8d7e55f /Documentation/hwmon
parent7de859fcf92c8990902faea594d0128c541d14f6 (diff)
downloadlinux-5d9ca430ea3ae87e41a69333ca30533e9cdc17cf.tar.xz
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>
Diffstat (limited to 'Documentation/hwmon')
-rw-r--r--Documentation/hwmon/ltc299024
1 files changed, 15 insertions, 9 deletions
diff --git a/Documentation/hwmon/ltc2990 b/Documentation/hwmon/ltc2990
index c25211e90bdc..3ed68f676c0f 100644
--- a/Documentation/hwmon/ltc2990
+++ b/Documentation/hwmon/ltc2990
@@ -8,6 +8,7 @@ Supported chips:
Datasheet: http://www.linear.com/product/ltc2990
Author: Mike Looijmans <mike.looijmans@topic.nl>
+ Tom Levens <tom.levens@cern.ch>
Description
@@ -16,10 +17,8 @@ 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
-measure current through a series resistor, or a temperature.
-
-This driver currently uses the 2x differential mode only. In order to support
-other modes, the driver will need to be expanded.
+measure current through a series resistor, or a temperature with an external
+diode.
Usage Notes
@@ -32,12 +31,19 @@ devices explicitly.
Sysfs attributes
----------------
+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
+
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.
-
-in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
-temp1_input Internal chip temperature 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.