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Kernel driver jc42 ================== Supported chips: * Analog Devices ADT7408 Prefix: 'adt7408' Addresses scanned: I2C 0x18 - 0x1f Datasheets: http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf * IDT TSE2002B3, TS3000B3 Prefix: 'tse2002b3', 'ts3000b3' Addresses scanned: I2C 0x18 - 0x1f Datasheets: http://www.idt.com/products/getdoc.cfm?docid=18715691 http://www.idt.com/products/getdoc.cfm?docid=18715692 * Maxim MAX6604 Prefix: 'max6604' Addresses scanned: I2C 0x18 - 0x1f Datasheets: http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf * Microchip MCP9805, MCP98242, MCP98243, MCP9843 Prefixes: 'mcp9805', 'mcp98242', 'mcp98243', 'mcp9843' Addresses scanned: I2C 0x18 - 0x1f Datasheets: http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf * NXP Semiconductors SE97, SE97B Prefix: 'se97' Addresses scanned: I2C 0x18 - 0x1f Datasheets: http://www.nxp.com/documents/data_sheet/SE97.pdf http://www.nxp.com/documents/data_sheet/SE97B.pdf * NXP Semiconductors SE98 Prefix: 'se98' Addresses scanned: I2C 0x18 - 0x1f Datasheets: http://www.nxp.com/documents/data_sheet/SE98.pdf * ON Semiconductor CAT34TS02, CAT6095 Prefix: 'cat34ts02', 'cat6095' Addresses scanned: I2C 0x18 - 0x1f Datasheet: http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF * ST Microelectronics STTS424, STTS424E02 Prefix: 'stts424' Addresses scanned: I2C 0x18 - 0x1f Datasheets: http://www.st.com/stonline/products/literature/ds/13447/stts424.pdf http://www.st.com/stonline/products/literature/ds/13448/stts424e02.pdf * JEDEC JC 42.4 compliant temperature sensor chips Prefix: 'jc42' Addresses scanned: I2C 0x18 - 0x1f |
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Datasheet: http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf |
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Author: Guenter Roeck <guenter.roeck@ericsson.com> Description ----------- |
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This driver implements support for JEDEC JC 42.4 compliant temperature sensors, which are used on many DDR3 memory modules for mobile devices and servers. Some systems use the sensor to prevent memory overheating by automatically throttling the memory controller. |
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The driver auto-detects the chips listed above, but can be manually instantiated to support other JC 42.4 compliant chips. Example: the following will load the driver for a generic JC 42.4 compliant temperature sensor at address 0x18 on I2C bus #1: # modprobe jc42 # echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum, and critical temperature can be configured. There are alarms for high, low, and critical thresholds. There is also an hysteresis to control the thresholds for resetting alarms. Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5, 3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those limits. The chip supports only a single register to configure the hysteresis, which applies to all limits. This register can be written by writing into 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 is likely that it has locked the registers, i.e., that the temperature limits cannot be changed. |
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Sysfs entries ------------- temp1_input Temperature (RO) |
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temp1_min Minimum temperature (RO or RW) temp1_max Maximum temperature (RO or RW) 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) temp1_min_alarm Temperature low alarm temp1_max_alarm Temperature high alarm temp1_crit_alarm Temperature critical alarm |