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1Kernel driver jc42
2==================
3
4Supported chips:
5 * Analog Devices ADT7408
6 Datasheets:
7 http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf
8 * Atmel AT30TS00, AT30TS002A/B, AT30TSE004A
9 Datasheets:
10 http://www.atmel.com/Images/doc8585.pdf
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
14 * IDT TSE2002B3, TSE2002GB2, TSE2004GB2, TS3000B3, TS3000GB0, TS3000GB2,
15 TS3001GB2
16 Datasheets:
17 Available from IDT web site
18 * Maxim MAX6604
19 Datasheets:
20 http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
21 * Microchip MCP9804, MCP9805, MCP9808, MCP98242, MCP98243, MCP98244, MCP9843
22 Datasheets:
23 http://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf
24 http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf
25 http://ww1.microchip.com/downloads/en/DeviceDoc/25095A.pdf
26 http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf
27 http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf
28 http://ww1.microchip.com/downloads/en/DeviceDoc/22327A.pdf
29 * NXP Semiconductors SE97, SE97B, SE98, SE98A
30 Datasheets:
31 http://www.nxp.com/documents/data_sheet/SE97.pdf
32 http://www.nxp.com/documents/data_sheet/SE97B.pdf
33 http://www.nxp.com/documents/data_sheet/SE98.pdf
34 http://www.nxp.com/documents/data_sheet/SE98A.pdf
35 * ON Semiconductor CAT34TS02, CAT6095
36 Datasheet:
37 http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
38 http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
39 * ST Microelectronics STTS424, STTS424E02, STTS2002, STTS2004, STTS3000
40 Datasheets:
41 http://www.st.com/web/en/resource/technical/document/datasheet/CD00157556.pdf
42 http://www.st.com/web/en/resource/technical/document/datasheet/CD00157558.pdf
43 http://www.st.com/web/en/resource/technical/document/datasheet/CD00266638.pdf
44 http://www.st.com/web/en/resource/technical/document/datasheet/CD00225278.pdf
45 http://www.st.com/web/en/resource/technical/document/datasheet/DM00076709.pdf
46 * JEDEC JC 42.4 compliant temperature sensor chips
47 Datasheet:
48 http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf
49
50 Common for all chips:
51 Prefix: 'jc42'
52 Addresses scanned: I2C 0x18 - 0x1f
53
54Author:
55 Guenter Roeck <linux@roeck-us.net>
56
57
58Description
59-----------
60
61This driver implements support for JEDEC JC 42.4 compliant temperature sensors,
62which are used on many DDR3 memory modules for mobile devices and servers. Some
63systems use the sensor to prevent memory overheating by automatically throttling
64the memory controller.
65
66The driver auto-detects the chips listed above, but can be manually instantiated
67to support other JC 42.4 compliant chips.
68
69Example: the following will load the driver for a generic JC 42.4 compliant
70temperature sensor at address 0x18 on I2C bus #1:
71
72# modprobe jc42
73# echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device
74
75A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
76and critical temperature can be configured. There are alarms for high, low,
77and critical thresholds.
78
79There is also an hysteresis to control the thresholds for resetting alarms.
80Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
813.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
82limits. The chip supports only a single register to configure the hysteresis,
83which applies to all limits. This register can be written by writing into
84temp1_crit_hyst. Other hysteresis attributes are read-only.
85
86If the BIOS has configured the sensor for automatic temperature management, it
87is likely that it has locked the registers, i.e., that the temperature limits
88cannot be changed.
89
90Sysfs entries
91-------------
92
93temp1_input Temperature (RO)
94temp1_min Minimum temperature (RO or RW)
95temp1_max Maximum temperature (RO or RW)
96temp1_crit Critical high temperature (RO or RW)
97
98temp1_crit_hyst Critical hysteresis temperature (RO or RW)
99temp1_max_hyst Maximum hysteresis temperature (RO)
100
101temp1_min_alarm Temperature low alarm
102temp1_max_alarm Temperature high alarm
103temp1_crit_alarm Temperature critical alarm