linux/Documentation/hwmon/lm95245
Guenter Roeck a41a8927e7 hwmon: (lm95245) Make temp2_crit_hyst read-only
The hysteresis register is shared among both temperature sensors.
This means changing one also affects the other. To avoid confusion,
established way to express this is to make only the first instance writable
and keep all other instances as read-only. Otherwise users may be
confused that changing the second writable value also affects the first,
while it is more obvious that a writable value may affect a different
read-only value.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Jean Delvare <jdelvare@suse.de>
2014-03-03 08:01:06 -08:00

38 lines
1.5 KiB
Plaintext

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.