| | 1 | Kernel driver jc42 |
| | 2 | ================== |
| | 3 | |
| | 4 | Supported chips: |
| | 5 | * Analog Devices ADT7408 |
| | 6 | Datasheets: |
| | 7 | http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf |
| | 8 | * Atmel AT30TS00 |
| | 9 | Datasheets: |
| | 10 | http://www.atmel.com/Images/doc8585.pdf |
| | 11 | * IDT TSE2002B3, TSE2002GB2, TS3000B3, TS3000GB2 |
| | 12 | Datasheets: |
| | 13 | http://www.idt.com/sites/default/files/documents/IDT_TSE2002B3C_DST_20100512_120303152056.pdf |
| | 14 | http://www.idt.com/sites/default/files/documents/IDT_TSE2002GB2A1_DST_20111107_120303145914.pdf |
| | 15 | http://www.idt.com/sites/default/files/documents/IDT_TS3000B3A_DST_20101129_120303152013.pdf |
| | 16 | http://www.idt.com/sites/default/files/documents/IDT_TS3000GB2A1_DST_20111104_120303151012.pdf |
| | 17 | * Maxim MAX6604 |
| | 18 | Datasheets: |
| | 19 | http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf |
| | 20 | * Microchip MCP9804, MCP9805, MCP98242, MCP98243, MCP9843 |
| | 21 | Datasheets: |
| | 22 | http://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf |
| | 23 | http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf |
| | 24 | http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf |
| | 25 | http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf |
| | 26 | * NXP Semiconductors SE97, SE97B, SE98, SE98A |
| | 27 | Datasheets: |
| | 28 | http://www.nxp.com/documents/data_sheet/SE97.pdf |
| | 29 | http://www.nxp.com/documents/data_sheet/SE97B.pdf |
| | 30 | http://www.nxp.com/documents/data_sheet/SE98.pdf |
| | 31 | http://www.nxp.com/documents/data_sheet/SE98A.pdf |
| | 32 | * ON Semiconductor CAT34TS02, CAT6095 |
| | 33 | Datasheet: |
| | 34 | http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF |
| | 35 | http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF |
| | 36 | * ST Microelectronics STTS424, STTS424E02, STTS2002, STTS3000 |
| | 37 | Datasheets: |
| | 38 | http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00157556.pdf |
| | 39 | http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00157558.pdf |
| | 40 | http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATASHEET/CD00225278.pdf |
| | 41 | http://www.st.com/internet/com/TECHNICAL_RESOURCES/TECHNICAL_LITERATURE/DATA_BRIEF/CD00270920.pdf |
| | 42 | * JEDEC JC 42.4 compliant temperature sensor chips |
| | 43 | Datasheet: |
| | 44 | http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf |
| | 45 | |
| | 46 | Common for all chips: |
| | 47 | Prefix: 'jc42' |
| | 48 | Addresses scanned: I2C 0x18 - 0x1f |
| | 49 | |
| | 50 | Author: |
| | 51 | Guenter Roeck <guenter.roeck@ericsson.com> |
| | 52 | |
| | 53 | |
| | 54 | Description |
| | 55 | ----------- |
| | 56 | |
| | 57 | This driver implements support for JEDEC JC 42.4 compliant temperature sensors, |
| | 58 | which are used on many DDR3 memory modules for mobile devices and servers. Some |
| | 59 | systems use the sensor to prevent memory overheating by automatically throttling |
| | 60 | the memory controller. |
| | 61 | |
| | 62 | The driver auto-detects the chips listed above, but can be manually instantiated |
| | 63 | to support other JC 42.4 compliant chips. |
| | 64 | |
| | 65 | Example: the following will load the driver for a generic JC 42.4 compliant |
| | 66 | temperature sensor at address 0x18 on I2C bus #1: |
| | 67 | |
| | 68 | # modprobe jc42 |
| | 69 | # echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device |
| | 70 | |
| | 71 | A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum, |
| | 72 | and critical temperature can be configured. There are alarms for high, low, |
| | 73 | and critical thresholds. |
| | 74 | |
| | 75 | There is also an hysteresis to control the thresholds for resetting alarms. |
| | 76 | Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5, |
| | 77 | 3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those |
| | 78 | limits. The chip supports only a single register to configure the hysteresis, |
| | 79 | which applies to all limits. This register can be written by writing into |
| | 80 | temp1_crit_hyst. Other hysteresis attributes are read-only. |
| | 81 | |
| | 82 | If the BIOS has configured the sensor for automatic temperature management, it |
| | 83 | is likely that it has locked the registers, i.e., that the temperature limits |
| | 84 | cannot be changed. |
| | 85 | |
| | 86 | Sysfs entries |
| | 87 | ------------- |
| | 88 | |
| | 89 | temp1_input Temperature (RO) |
| | 90 | temp1_min Minimum temperature (RO or RW) |
| | 91 | temp1_max Maximum temperature (RO or RW) |
| | 92 | temp1_crit Critical high temperature (RO or RW) |
| | 93 | |
| | 94 | temp1_crit_hyst Critical hysteresis temperature (RO or RW) |
| | 95 | temp1_max_hyst Maximum hysteresis temperature (RO) |
| | 96 | |
| | 97 | temp1_min_alarm Temperature low alarm |
| | 98 | temp1_max_alarm Temperature high alarm |
| | 99 | temp1_crit_alarm Temperature critical alarm |
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