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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>
38 lines
1.5 KiB
Plaintext
38 lines
1.5 KiB
Plaintext
Kernel driver lm95245
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==================
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Supported chips:
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* National Semiconductor LM95245
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Addresses scanned: I2C 0x18, 0x19, 0x29, 0x4c, 0x4d
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Datasheet: Publicly available at the National Semiconductor website
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http://www.national.com/mpf/LM/LM95245.html
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Author: Alexander Stein <alexander.stein@systec-electronic.com>
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Description
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-----------
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The LM95245 is an 11-bit digital temperature sensor with a 2-wire System
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Management Bus (SMBus) interface and TruTherm technology that can monitor
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the temperature of a remote diode as well as its own temperature.
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The LM95245 can be used to very accurately monitor the temperature of
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external devices such as microprocessors.
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All temperature values are given in millidegrees Celsius. Local temperature
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is given within a range of -127 to +127.875 degrees. Remote temperatures are
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given within a range of -127 to +255 degrees. Resolution depends on
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temperature input and range.
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Each sensor has its own critical limit. Additionally, there is a relative
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hysteresis value common to both critical limits. To make life easier to
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user-space applications, two absolute values are exported, one for each
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channel, but these values are of course linked. Only the local hysteresis
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can be set from user-space, and the same delta applies to the remote
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hysteresis.
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The lm95245 driver can change its update interval to a fixed set of values.
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It will round up to the next selectable interval. See the datasheet for exact
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values. Reading sensor values more often will do no harm, but will return
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'old' values.
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