projects / deliverable / linux.git / blame
| Commit | Line | Data |
|---|---|---|
| 4453d736 GR |
1 | Kernel driver jc42 |
| 2 | ================== | |
| 3 | ||
| 4 | Supported chips: | |
| 5 | * Analog Devices ADT7408 | |
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6 | Datasheets: |
| 7 | http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf | |
| 1bd612a2 | 8 | * Atmel AT30TS00 |
| 4453d736 | 9 | Datasheets: |
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10 | http://www.atmel.com/Images/doc8585.pdf |
| 11 | * IDT TSE2002B3, TSE2002GB2, TS3000B3, TS3000GB2 | |
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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 | |
| 4453d736 | 17 | * Maxim MAX6604 |
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18 | Datasheets: |
| 19 | http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf | |
| 1bd612a2 | 20 | * Microchip MCP9804, MCP9805, MCP98242, MCP98243, MCP9843 |
| 4453d736 | 21 | Datasheets: |
| 1bd612a2 | 22 | http://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf |
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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 | |
| 86dda176 | 26 | * NXP Semiconductors SE97, SE97B, SE98, SE98A |
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27 | Datasheets: |
| 28 | http://www.nxp.com/documents/data_sheet/SE97.pdf | |
| 29 | http://www.nxp.com/documents/data_sheet/SE97B.pdf | |
| 4453d736 | 30 | http://www.nxp.com/documents/data_sheet/SE98.pdf |
| 86dda176 | 31 | http://www.nxp.com/documents/data_sheet/SE98A.pdf |
| 4453d736 | 32 | * ON Semiconductor CAT34TS02, CAT6095 |
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33 | Datasheet: |
| 34 | http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF | |
| 35 | http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF | |
| 86dda176 | 36 | * ST Microelectronics STTS424, STTS424E02, STTS2002, STTS3000 |
| 4de86126 | 37 | Datasheets: |
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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 | |
| 4de86126 JD |
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 | |
| 4453d736 | 42 | * JEDEC JC 42.4 compliant temperature sensor chips |
| d5622f5b CL |
43 | Datasheet: |
| 44 | http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf | |
| 4453d736 | 45 | |
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46 | Common for all chips: |
| 47 | Prefix: 'jc42' | |
| 48 | Addresses scanned: I2C 0x18 - 0x1f | |
| 49 | ||
| 4453d736 GR |
50 | Author: |
| 51 | Guenter Roeck <guenter.roeck@ericsson.com> | |
| 52 | ||
| 53 | ||
| 54 | Description | |
| 55 | ----------- | |
| 56 | ||
| d5622f5b CL |
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 | ||
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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 | ||
| 2c6315da CL |
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 | ||
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86 | Sysfs entries |
| 87 | ------------- | |
| 88 | ||
| 89 | temp1_input Temperature (RO) | |
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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) | |
| 4453d736 | 93 | |
| 2c6315da | 94 | temp1_crit_hyst Critical hysteresis temperature (RO or RW) |
| 4453d736 GR |
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 |