tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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, TS3000B3, TS3000GB2
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
20 * Maxim MAX6604
21 Datasheets:
22 http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
23 * Microchip MCP9804, MCP9805, MCP98242, MCP98243, MCP98244, MCP9843
24 Datasheets:
25 http://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf
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
29 http://ww1.microchip.com/downloads/en/DeviceDoc/22327A.pdf
30 * NXP Semiconductors SE97, SE97B, SE98, SE98A
31 Datasheets:
32 http://www.nxp.com/documents/data_sheet/SE97.pdf
33 http://www.nxp.com/documents/data_sheet/SE97B.pdf
34 http://www.nxp.com/documents/data_sheet/SE98.pdf
35 http://www.nxp.com/documents/data_sheet/SE98A.pdf
36 * ON Semiconductor CAT34TS02, CAT6095
37 Datasheet:
38 http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
39 http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
40 * ST Microelectronics STTS424, STTS424E02, STTS2002, STTS2004, STTS3000
41 Datasheets:
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
47 * JEDEC JC 42.4 compliant temperature sensor chips
48 Datasheet:
49 http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf
50
51 Common for all chips:
52 Prefix: 'jc42'
53 Addresses scanned: I2C 0x18 - 0x1f
54
55Author:
56 Guenter Roeck <linux@roeck-us.net>
57
58
59Description
60-----------
61
62This driver implements support for JEDEC JC 42.4 compliant temperature sensors,
63which are used on many DDR3 memory modules for mobile devices and servers. Some
64systems use the sensor to prevent memory overheating by automatically throttling
65the memory controller.
66
67The driver auto-detects the chips listed above, but can be manually instantiated
68to support other JC 42.4 compliant chips.
69
70Example: the following will load the driver for a generic JC 42.4 compliant
71temperature 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
76A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
77and critical temperature can be configured. There are alarms for high, low,
78and critical thresholds.
79
80There is also an hysteresis to control the thresholds for resetting alarms.
81Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
823.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
83limits. The chip supports only a single register to configure the hysteresis,
84which applies to all limits. This register can be written by writing into
85temp1_crit_hyst. Other hysteresis attributes are read-only.
86
87If the BIOS has configured the sensor for automatic temperature management, it
88is likely that it has locked the registers, i.e., that the temperature limits
89cannot be changed.
90
91Sysfs entries
92-------------
93
94temp1_input Temperature (RO)
95temp1_min Minimum temperature (RO or RW)
96temp1_max Maximum temperature (RO or RW)
97temp1_crit Critical high temperature (RO or RW)
98
99temp1_crit_hyst Critical hysteresis temperature (RO or RW)
100temp1_max_hyst Maximum hysteresis temperature (RO)
101
102temp1_min_alarm Temperature low alarm
103temp1_max_alarm Temperature high alarm
104temp1_crit_alarm Temperature critical alarm