[mirror_ubuntu-bionic-kernel.git] / Documentation / hwmon / lm95245

Kernel driver lm95245
==================

Supported chips:
  * National Semiconductor LM95245
    Addresses scanned: I2C 0x18, 0x19, 0x29, 0x4c, 0x4d
    Datasheet: Publicly available at the National Semiconductor website
               http://www.national.com/mpf/LM/LM95245.html


Author: Alexander Stein <alexander.stein@systec-electronic.com>

Description
-----------

The LM95245 is an 11-bit digital temperature sensor with a 2-wire System
Management Bus (SMBus) interface and TruTherm technology that can monitor
the temperature of a remote diode as well as its own temperature.
The LM95245 can be used to very accurately monitor the temperature of
external devices such as microprocessors.

All temperature values are given in millidegrees Celsius. Local temperature
is given within a range of -127 to +127.875 degrees. Remote temperatures are
given within a range of -127 to +255 degrees. Resolution depends on
temperature input and range.

Each sensor has its own critical limit. Additionally, there is a relative
hysteresis value common to both critical limits. To make life easier to
user-space applications, two absolute values are exported, one for each
channel, but these values are of course linked. Only the local hysteresis
can be set from user-space, and the same delta applies to the remote
hysteresis.

The lm95245 driver can change its update interval to a fixed set of values.
It will round up to the next selectable interval. See the datasheet for exact
values. Reading sensor values more often will do no harm, but will return
'old' values.
Commit	Line	Data
fffd80cc AS	1	Kernel driver lm95245
	2	==================
	3
	4	Supported chips:
	5	* National Semiconductor LM95245
	6	Addresses scanned: I2C 0x18, 0x19, 0x29, 0x4c, 0x4d
	7	Datasheet: Publicly available at the National Semiconductor website
	8	http://www.national.com/mpf/LM/LM95245.html
	9
	10
	11	Author: Alexander Stein <alexander.stein@systec-electronic.com>
	12
	13	Description
	14	-----------
	15
	16	The LM95245 is an 11-bit digital temperature sensor with a 2-wire System
	17	Management Bus (SMBus) interface and TruTherm technology that can monitor
	18	the temperature of a remote diode as well as its own temperature.
	19	The LM95245 can be used to very accurately monitor the temperature of
	20	external devices such as microprocessors.
	21
	22	All temperature values are given in millidegrees Celsius. Local temperature
	23	is given within a range of -127 to +127.875 degrees. Remote temperatures are
	24	given within a range of -127 to +255 degrees. Resolution depends on
	25	temperature input and range.
	26
a41a8927 GR	27	Each sensor has its own critical limit. Additionally, there is a relative
	28	hysteresis value common to both critical limits. To make life easier to
	29	user-space applications, two absolute values are exported, one for each
	30	channel, but these values are of course linked. Only the local hysteresis
	31	can be set from user-space, and the same delta applies to the remote
	32	hysteresis.
fffd80cc AS	33
	34	The lm95245 driver can change its update interval to a fixed set of values.
	35	It will round up to the next selectable interval. See the datasheet for exact
	36	values. Reading sensor values more often will do no harm, but will return
	37	'old' values.