Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/Documentation/hwmon/ltc2990 b/Documentation/hwmon/ltc2990
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+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>
+        Tom Levens <tom.levens@cern.ch>
+
+
+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 with an external
+diode.
+
+
+Usage Notes
+-----------
+
+This driver does not probe for PMBus devices. You will have to instantiate
+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.