167 lines
4.2 KiB
ReStructuredText
167 lines
4.2 KiB
ReStructuredText
Kernel driver lm75
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==================
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Supported chips:
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* National Semiconductor LM75
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Prefix: 'lm75'
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Addresses scanned: I2C 0x48 - 0x4f
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Datasheet: Publicly available at the National Semiconductor website
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http://www.national.com/
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* National Semiconductor LM75A
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Prefix: 'lm75a'
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Addresses scanned: I2C 0x48 - 0x4f
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Datasheet: Publicly available at the National Semiconductor website
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http://www.national.com/
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* Dallas Semiconductor (now Maxim) DS75, DS1775, DS7505
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Prefixes: 'ds75', 'ds1775', 'ds7505'
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Addresses scanned: none
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Datasheet: Publicly available at the Maxim website
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https://www.maximintegrated.com/
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* Maxim MAX6625, MAX6626, MAX31725, MAX31726
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Prefixes: 'max6625', 'max6626', 'max31725', 'max31726'
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Addresses scanned: none
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Datasheet: Publicly available at the Maxim website
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http://www.maxim-ic.com/
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* Microchip (TelCom) TCN75
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Prefix: 'tcn75'
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Addresses scanned: none
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Datasheet: Publicly available at the Microchip website
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http://www.microchip.com/
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* Microchip MCP9800, MCP9801, MCP9802, MCP9803
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Prefix: 'mcp980x'
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Addresses scanned: none
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Datasheet: Publicly available at the Microchip website
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http://www.microchip.com/
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* Analog Devices ADT75
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Prefix: 'adt75'
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Addresses scanned: none
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Datasheet: Publicly available at the Analog Devices website
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https://www.analog.com/adt75
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* ST Microelectronics STDS75
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Prefix: 'stds75'
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Addresses scanned: none
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Datasheet: Publicly available at the ST website
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http://www.st.com/internet/analog/product/121769.jsp
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* ST Microelectronics STLM75
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Prefix: 'stlm75'
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Addresses scanned: none
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Datasheet: Publicly available at the ST website
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https://www.st.com/resource/en/datasheet/stlm75.pdf
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* Texas Instruments TMP100, TMP101, TMP105, TMP112, TMP75, TMP75B, TMP75C, TMP175, TMP275, TMP1075
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Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp112', 'tmp175', 'tmp75', 'tmp75b', 'tmp75c', 'tmp275', 'tmp1075'
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Addresses scanned: none
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Datasheet: Publicly available at the Texas Instruments website
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https://www.ti.com/product/tmp100
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https://www.ti.com/product/tmp101
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https://www.ti.com/product/tmp105
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https://www.ti.com/product/tmp112
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https://www.ti.com/product/tmp75
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https://www.ti.com/product/tmp75b
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https://www.ti.com/product/tmp75c
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https://www.ti.com/product/tmp175
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https://www.ti.com/product/tmp275
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https://www.ti.com/product/TMP1075
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* NXP LM75B, PCT2075
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Prefix: 'lm75b', 'pct2075'
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Addresses scanned: none
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Datasheet: Publicly available at the NXP website
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https://www.nxp.com/documents/data_sheet/LM75B.pdf
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https://www.nxp.com/docs/en/data-sheet/PCT2075.pdf
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Author: Frodo Looijaard <frodol@dds.nl>
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Description
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-----------
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The LM75 implements one temperature sensor. Limits can be set through the
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Overtemperature Shutdown register and Hysteresis register. Each value can be
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set and read to half-degree accuracy.
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An alarm is issued (usually to a connected LM78) when the temperature
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gets higher then the Overtemperature Shutdown value; it stays on until
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the temperature falls below the Hysteresis value.
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All temperatures are in degrees Celsius, and are guaranteed within a
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range of -55 to +125 degrees.
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The driver caches the values for a period varying between 1 second for the
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slowest chips and 125 ms for the fastest chips; reading it more often
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will do no harm, but will return 'old' values.
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The original LM75 was typically used in combination with LM78-like chips
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on PC motherboards, to measure the temperature of the processor(s). Clones
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are now used in various embedded designs.
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The LM75 is essentially an industry standard; there may be other
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LM75 clones not listed here, with or without various enhancements,
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that are supported. The clones are not detected by the driver, unless
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they reproduce the exact register tricks of the original LM75, and must
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therefore be instantiated explicitly. Higher resolution up to 16-bit
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is supported by this driver, other specific enhancements are not.
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The LM77 is not supported, contrary to what we pretended for a long time.
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Both chips are simply not compatible, value encoding differs.
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