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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 | |
175c490c | 8 | * Atmel AT30TS00, AT30TS002A/B, AT30TSE004A |
4453d736 | 9 | Datasheets: |
1bd612a2 | 10 | http://www.atmel.com/Images/doc8585.pdf |
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11 | http://www.atmel.com/Images/doc8711.pdf |
12 | http://www.atmel.com/Images/Atmel-8852-SEEPROM-AT30TSE002A-Datasheet.pdf | |
13 | http://www.atmel.com/Images/Atmel-8868-DTS-AT30TSE004A-Datasheet.pdf | |
1bd612a2 | 14 | * IDT TSE2002B3, TSE2002GB2, TS3000B3, TS3000GB2 |
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15 | Datasheets: |
16 | http://www.idt.com/sites/default/files/documents/IDT_TSE2002B3C_DST_20100512_120303152056.pdf | |
17 | http://www.idt.com/sites/default/files/documents/IDT_TSE2002GB2A1_DST_20111107_120303145914.pdf | |
18 | http://www.idt.com/sites/default/files/documents/IDT_TS3000B3A_DST_20101129_120303152013.pdf | |
19 | http://www.idt.com/sites/default/files/documents/IDT_TS3000GB2A1_DST_20111104_120303151012.pdf | |
4453d736 | 20 | * Maxim MAX6604 |
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21 | Datasheets: |
22 | http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf | |
d4768280 | 23 | * Microchip MCP9804, MCP9805, MCP98242, MCP98243, MCP98244, MCP9843 |
4453d736 | 24 | Datasheets: |
1bd612a2 | 25 | http://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf |
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26 | http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf |
27 | http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf | |
28 | http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf | |
d4768280 | 29 | http://ww1.microchip.com/downloads/en/DeviceDoc/22327A.pdf |
86dda176 | 30 | * NXP Semiconductors SE97, SE97B, SE98, SE98A |
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31 | Datasheets: |
32 | http://www.nxp.com/documents/data_sheet/SE97.pdf | |
33 | http://www.nxp.com/documents/data_sheet/SE97B.pdf | |
4453d736 | 34 | http://www.nxp.com/documents/data_sheet/SE98.pdf |
86dda176 | 35 | http://www.nxp.com/documents/data_sheet/SE98A.pdf |
4453d736 | 36 | * ON Semiconductor CAT34TS02, CAT6095 |
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37 | Datasheet: |
38 | http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF | |
39 | http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF | |
175c490c | 40 | * ST Microelectronics STTS424, STTS424E02, STTS2002, STTS2004, STTS3000 |
4de86126 | 41 | Datasheets: |
175c490c GR |
42 | http://www.st.com/web/en/resource/technical/document/datasheet/CD00157556.pdf |
43 | http://www.st.com/web/en/resource/technical/document/datasheet/CD00157558.pdf | |
44 | http://www.st.com/web/en/resource/technical/document/datasheet/CD00266638.pdf | |
45 | http://www.st.com/web/en/resource/technical/document/datasheet/CD00225278.pdf | |
46 | http://www.st.com/web/en/resource/technical/document/datasheet/DM00076709.pdf | |
4453d736 | 47 | * JEDEC JC 42.4 compliant temperature sensor chips |
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48 | Datasheet: |
49 | http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf | |
4453d736 | 50 | |
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51 | Common for all chips: |
52 | Prefix: 'jc42' | |
53 | Addresses scanned: I2C 0x18 - 0x1f | |
54 | ||
4453d736 | 55 | Author: |
e3333e57 | 56 | Guenter Roeck <linux@roeck-us.net> |
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57 | |
58 | ||
59 | Description | |
60 | ----------- | |
61 | ||
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62 | This driver implements support for JEDEC JC 42.4 compliant temperature sensors, |
63 | which are used on many DDR3 memory modules for mobile devices and servers. Some | |
64 | systems use the sensor to prevent memory overheating by automatically throttling | |
65 | the memory controller. | |
66 | ||
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67 | The driver auto-detects the chips listed above, but can be manually instantiated |
68 | to support other JC 42.4 compliant chips. | |
69 | ||
70 | Example: the following will load the driver for a generic JC 42.4 compliant | |
71 | temperature sensor at address 0x18 on I2C bus #1: | |
72 | ||
73 | # modprobe jc42 | |
74 | # echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device | |
75 | ||
76 | A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum, | |
77 | and critical temperature can be configured. There are alarms for high, low, | |
78 | and critical thresholds. | |
79 | ||
80 | There is also an hysteresis to control the thresholds for resetting alarms. | |
81 | Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5, | |
82 | 3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those | |
83 | limits. The chip supports only a single register to configure the hysteresis, | |
84 | which applies to all limits. This register can be written by writing into | |
85 | temp1_crit_hyst. Other hysteresis attributes are read-only. | |
86 | ||
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87 | If the BIOS has configured the sensor for automatic temperature management, it |
88 | is likely that it has locked the registers, i.e., that the temperature limits | |
89 | cannot be changed. | |
90 | ||
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91 | Sysfs entries |
92 | ------------- | |
93 | ||
94 | temp1_input Temperature (RO) | |
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95 | temp1_min Minimum temperature (RO or RW) |
96 | temp1_max Maximum temperature (RO or RW) | |
97 | temp1_crit Critical high temperature (RO or RW) | |
4453d736 | 98 | |
2c6315da | 99 | temp1_crit_hyst Critical hysteresis temperature (RO or RW) |
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100 | temp1_max_hyst Maximum hysteresis temperature (RO) |
101 | ||
102 | temp1_min_alarm Temperature low alarm | |
103 | temp1_max_alarm Temperature high alarm | |
104 | temp1_crit_alarm Temperature critical alarm |