[linux-block.git] / Documentation / hwmon / ltc2990.rst

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 Celsius
============= ==================================================

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 Celsius
temp3_input   External temperature sensor TR2 in millidegrees Celsius
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.
Commit	Line	Data
	1	Kernel driver ltc2990
	2	=====================
	3
	4
	5	Supported chips:
	6
	7	* Linear Technology LTC2990
	8
	9	Prefix: 'ltc2990'
	10
	11	Addresses scanned: -
	12
	13	Datasheet: http://www.linear.com/product/ltc2990
	14
	15
	16
	17	Author:
	18
	19	- Mike Looijmans <mike.looijmans@topic.nl>
	20	- Tom Levens <tom.levens@cern.ch>
	21
	22
	23	Description
	24	-----------
	25
	26	LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor.
	27	The chip's inputs can measure 4 voltages, or two inputs together (1+2 and 3+4)
	28	can be combined to measure a differential voltage, which is typically used to
	29	measure current through a series resistor, or a temperature with an external
	30	diode.
	31
	32
	33	Usage Notes
	34	-----------
	35
	36	This driver does not probe for PMBus devices. You will have to instantiate
	37	devices explicitly.
	38
	39
	40	Sysfs attributes
	41	----------------
	42
	43	============= ==================================================
	44	in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
	45	temp1_input Internal chip temperature in millidegrees Celsius
	46	============= ==================================================
	47
	48	A subset of the following attributes are visible, depending on the measurement
	49	mode of the chip.
	50
	51	============= ==========================================================
	52	in[1-4]_input Voltage at V[1-4] pin in millivolt
	53	temp2_input External temperature sensor TR1 in millidegrees Celsius
	54	temp3_input External temperature sensor TR2 in millidegrees Celsius
	55	curr1_input Current in mA across V1-V2 assuming a 1mOhm sense resistor
	56	curr2_input Current in mA across V3-V4 assuming a 1mOhm sense resistor
	57	============= ==========================================================
	58
	59	The "curr*_input" measurements actually report the voltage drop across the
	60	input pins in microvolts. This is equivalent to the current through a 1mOhm
	61	sense resistor. Divide the reported value by the actual sense resistor value
	62	in mOhm to get the actual value.