426343ef34
Explain why clones of the LM75 are generally not detected by the driver, and why this isn't going to change. Also update the documentation to reflect the list of chip names currently supported by the driver. Signed-off-by: Jean Delvare <khali@linux-fr.org> Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
86 lines
3.5 KiB
Plaintext
86 lines
3.5 KiB
Plaintext
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 DS75, DS1775
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Prefixes: 'ds75', 'ds1775'
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Addresses scanned: none
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Datasheet: Publicly available at the Dallas Semiconductor website
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http://www.maxim-ic.com/
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* Maxim MAX6625, MAX6626
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Prefixes: 'max6625', 'max6626'
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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: 'lm75'
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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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http://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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* Texas Instruments TMP100, TMP101, TMP105, TMP75, TMP175, TMP275
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Prefixes: 'tmp100', 'tmp101', 'tmp105', 'tmp175', 'tmp75', 'tmp275'
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Addresses scanned: none
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Datasheet: Publicly available at the Texas Instruments website
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http://www.ti.com/product/tmp100
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http://www.ti.com/product/tmp101
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http://www.ti.com/product/tmp105
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http://www.ti.com/product/tmp75
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http://www.ti.com/product/tmp175
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http://www.ti.com/product/tmp275
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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 LM75 only updates its values each 1.5 seconds; 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. The specific enhancements (such as
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higher resolution) are not currently supported by the driver.
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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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