a31887dc9b
MCP9808 is not officially compliant to JC-42, similar to MCP9804, but its registers are compatible to JC-42. Signed-off-by: Alison Schofield <amsfield22@gmail.com> Cc: Daniel Baluta <daniel.baluta@gmail.com> Signed-off-by: Guenter Roeck <linux@roeck-us.net>
103 lines
4.1 KiB
Text
103 lines
4.1 KiB
Text
Kernel driver jc42
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==================
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Supported chips:
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* Analog Devices ADT7408
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Datasheets:
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http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf
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* Atmel AT30TS00, AT30TS002A/B, AT30TSE004A
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Datasheets:
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http://www.atmel.com/Images/doc8585.pdf
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http://www.atmel.com/Images/doc8711.pdf
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http://www.atmel.com/Images/Atmel-8852-SEEPROM-AT30TSE002A-Datasheet.pdf
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http://www.atmel.com/Images/Atmel-8868-DTS-AT30TSE004A-Datasheet.pdf
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* IDT TSE2002B3, TSE2002GB2, TSE2004GB2, TS3000B3, TS3000GB0, TS3000GB2,
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TS3001GB2
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Datasheets:
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Available from IDT web site
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* Maxim MAX6604
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Datasheets:
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http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
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* Microchip MCP9804, MCP9805, MCP9808, MCP98242, MCP98243, MCP98244, MCP9843
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Datasheets:
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http://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf
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http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf
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http://ww1.microchip.com/downloads/en/DeviceDoc/25095A.pdf
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http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf
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http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf
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http://ww1.microchip.com/downloads/en/DeviceDoc/22327A.pdf
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* NXP Semiconductors SE97, SE97B, SE98, SE98A
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Datasheets:
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http://www.nxp.com/documents/data_sheet/SE97.pdf
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http://www.nxp.com/documents/data_sheet/SE97B.pdf
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http://www.nxp.com/documents/data_sheet/SE98.pdf
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http://www.nxp.com/documents/data_sheet/SE98A.pdf
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* ON Semiconductor CAT34TS02, CAT6095
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Datasheet:
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http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
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http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
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* ST Microelectronics STTS424, STTS424E02, STTS2002, STTS2004, STTS3000
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Datasheets:
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http://www.st.com/web/en/resource/technical/document/datasheet/CD00157556.pdf
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http://www.st.com/web/en/resource/technical/document/datasheet/CD00157558.pdf
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http://www.st.com/web/en/resource/technical/document/datasheet/CD00266638.pdf
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http://www.st.com/web/en/resource/technical/document/datasheet/CD00225278.pdf
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http://www.st.com/web/en/resource/technical/document/datasheet/DM00076709.pdf
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* JEDEC JC 42.4 compliant temperature sensor chips
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Datasheet:
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http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf
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Common for all chips:
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Prefix: 'jc42'
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Addresses scanned: I2C 0x18 - 0x1f
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Author:
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Guenter Roeck <linux@roeck-us.net>
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Description
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-----------
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This driver implements support for JEDEC JC 42.4 compliant temperature sensors,
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which are used on many DDR3 memory modules for mobile devices and servers. Some
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systems use the sensor to prevent memory overheating by automatically throttling
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the memory controller.
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The driver auto-detects the chips listed above, but can be manually instantiated
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to support other JC 42.4 compliant chips.
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Example: the following will load the driver for a generic JC 42.4 compliant
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temperature sensor at address 0x18 on I2C bus #1:
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# modprobe jc42
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# echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device
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A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
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and critical temperature can be configured. There are alarms for high, low,
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and critical thresholds.
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There is also an hysteresis to control the thresholds for resetting alarms.
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Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
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3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
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limits. The chip supports only a single register to configure the hysteresis,
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which applies to all limits. This register can be written by writing into
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temp1_crit_hyst. Other hysteresis attributes are read-only.
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If the BIOS has configured the sensor for automatic temperature management, it
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is likely that it has locked the registers, i.e., that the temperature limits
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cannot be changed.
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Sysfs entries
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-------------
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temp1_input Temperature (RO)
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temp1_min Minimum temperature (RO or RW)
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temp1_max Maximum temperature (RO or RW)
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temp1_crit Critical high temperature (RO or RW)
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temp1_crit_hyst Critical hysteresis temperature (RO or RW)
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temp1_max_hyst Maximum hysteresis temperature (RO)
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temp1_min_alarm Temperature low alarm
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temp1_max_alarm Temperature high alarm
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temp1_crit_alarm Temperature critical alarm
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