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Guenter Roeck4453d732010-08-09 17:21:08 -07001Kernel driver jc42
2==================
3
4Supported chips:
5 * Analog Devices ADT7408
6 Prefix: 'adt7408'
7 Addresses scanned: I2C 0x18 - 0x1f
8 Datasheets:
9 http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf
10 * IDT TSE2002B3, TS3000B3
11 Prefix: 'tse2002b3', 'ts3000b3'
12 Addresses scanned: I2C 0x18 - 0x1f
13 Datasheets:
14 http://www.idt.com/products/getdoc.cfm?docid=18715691
15 http://www.idt.com/products/getdoc.cfm?docid=18715692
16 * Maxim MAX6604
17 Prefix: 'max6604'
18 Addresses scanned: I2C 0x18 - 0x1f
19 Datasheets:
20 http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
21 * Microchip MCP9805, MCP98242, MCP98243, MCP9843
22 Prefixes: 'mcp9805', 'mcp98242', 'mcp98243', 'mcp9843'
23 Addresses scanned: I2C 0x18 - 0x1f
24 Datasheets:
25 http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf
26 http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf
27 http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf
28 * NXP Semiconductors SE97, SE97B
29 Prefix: 'se97'
30 Addresses scanned: I2C 0x18 - 0x1f
31 Datasheets:
32 http://www.nxp.com/documents/data_sheet/SE97.pdf
33 http://www.nxp.com/documents/data_sheet/SE97B.pdf
34 * NXP Semiconductors SE98
35 Prefix: 'se98'
36 Addresses scanned: I2C 0x18 - 0x1f
37 Datasheets:
38 http://www.nxp.com/documents/data_sheet/SE98.pdf
39 * ON Semiconductor CAT34TS02, CAT6095
40 Prefix: 'cat34ts02', 'cat6095'
41 Addresses scanned: I2C 0x18 - 0x1f
42 Datasheet:
43 http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
44 http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
45 * ST Microelectronics STTS424, STTS424E02
46 Prefix: 'stts424'
47 Addresses scanned: I2C 0x18 - 0x1f
48 Datasheets:
49 http://www.st.com/stonline/products/literature/ds/13447/stts424.pdf
50 http://www.st.com/stonline/products/literature/ds/13448/stts424e02.pdf
51 * JEDEC JC 42.4 compliant temperature sensor chips
52 Prefix: 'jc42'
53 Addresses scanned: I2C 0x18 - 0x1f
Clemens Ladischd5622f52011-02-16 08:02:08 -050054 Datasheet:
55 http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf
Guenter Roeck4453d732010-08-09 17:21:08 -070056
57Author:
58 Guenter Roeck <guenter.roeck@ericsson.com>
59
60
61Description
62-----------
63
Clemens Ladischd5622f52011-02-16 08:02:08 -050064This driver implements support for JEDEC JC 42.4 compliant temperature sensors,
65which are used on many DDR3 memory modules for mobile devices and servers. Some
66systems use the sensor to prevent memory overheating by automatically throttling
67the memory controller.
68
Guenter Roeck4453d732010-08-09 17:21:08 -070069The driver auto-detects the chips listed above, but can be manually instantiated
70to support other JC 42.4 compliant chips.
71
72Example: the following will load the driver for a generic JC 42.4 compliant
73temperature sensor at address 0x18 on I2C bus #1:
74
75# modprobe jc42
76# echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device
77
78A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
79and critical temperature can be configured. There are alarms for high, low,
80and critical thresholds.
81
82There is also an hysteresis to control the thresholds for resetting alarms.
83Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
843.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
85limits. The chip supports only a single register to configure the hysteresis,
86which applies to all limits. This register can be written by writing into
87temp1_crit_hyst. Other hysteresis attributes are read-only.
88
Clemens Ladisch2c6315d2011-02-16 08:02:38 -050089If the BIOS has configured the sensor for automatic temperature management, it
90is likely that it has locked the registers, i.e., that the temperature limits
91cannot be changed.
92
Guenter Roeck4453d732010-08-09 17:21:08 -070093Sysfs entries
94-------------
95
96temp1_input Temperature (RO)
Clemens Ladisch2c6315d2011-02-16 08:02:38 -050097temp1_min Minimum temperature (RO or RW)
98temp1_max Maximum temperature (RO or RW)
99temp1_crit Critical high temperature (RO or RW)
Guenter Roeck4453d732010-08-09 17:21:08 -0700100
Clemens Ladisch2c6315d2011-02-16 08:02:38 -0500101temp1_crit_hyst Critical hysteresis temperature (RO or RW)
Guenter Roeck4453d732010-08-09 17:21:08 -0700102temp1_max_hyst Maximum hysteresis temperature (RO)
103
104temp1_min_alarm Temperature low alarm
105temp1_max_alarm Temperature high alarm
106temp1_crit_alarm Temperature critical alarm