| Kernel driver jc42 |
| ================== |
| |
| Supported chips: |
| * Analog Devices ADT7408 |
| Datasheets: |
| http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf |
| * Atmel AT30TS00 |
| Datasheets: |
| http://www.atmel.com/Images/doc8585.pdf |
| * IDT TSE2002B3, TSE2002GB2, TS3000B3, TS3000GB2 |
| Datasheets: |
| http://www.idt.com/sites/default/files/documents/IDT_TSE2002B3C_DST_20100512_120303152056.pdf |
| http://www.idt.com/sites/default/files/documents/IDT_TSE2002GB2A1_DST_20111107_120303145914.pdf |
| http://www.idt.com/sites/default/files/documents/IDT_TS3000B3A_DST_20101129_120303152013.pdf |
| http://www.idt.com/sites/default/files/documents/IDT_TS3000GB2A1_DST_20111104_120303151012.pdf |
| * Maxim MAX6604 |
| Datasheets: |
| http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf |
| * Microchip MCP9804, MCP9805, MCP98242, MCP98243, MCP9843 |
| Datasheets: |
| http://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf |
| 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, SE98, SE98A |
| Datasheets: |
| http://www.nxp.com/documents/data_sheet/SE97.pdf |
| http://www.nxp.com/documents/data_sheet/SE97B.pdf |
| http://www.nxp.com/documents/data_sheet/SE98.pdf |
| http://www.nxp.com/documents/data_sheet/SE98A.pdf |
| * ON Semiconductor CAT34TS02, CAT6095 |
| Datasheet: |
| http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF |
| http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF |
| * ST Microelectronics STTS424, STTS424E02, STTS2002, STTS3000 |
| Datasheets: |
| http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00157556.pdf |
| http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00157558.pdf |
| http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00225278.pdf |
| http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATA_BRIEF/CD00270920.pdf |
| * JEDEC JC 42.4 compliant temperature sensor chips |
| Datasheet: |
| http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf |
| |
| Common for all chips: |
| Prefix: 'jc42' |
| Addresses scanned: I2C 0x18 - 0x1f |
| |
| Author: |
| Guenter Roeck <guenter.roeck@ericsson.com> |
| |
| |
| Description |
| ----------- |
| |
| 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. |
| |
| 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. |
| |
| 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. |
| |
| Sysfs entries |
| ------------- |
| |
| temp1_input Temperature (RO) |
| temp1_min Minimum temperature (RO or RW) |
| temp1_max Maximum temperature (RO or RW) |
| temp1_crit Critical high temperature (RO or RW) |
| |
| temp1_crit_hyst Critical hysteresis temperature (RO or RW) |
| 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 |