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Documentation / hwmon / jc42


Based on kernel version 4.16.1. Page generated on 2018-04-09 11:53 EST.

1	Kernel driver jc42
2	==================
3	
4	Supported 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	
54	Author:
55		Guenter Roeck <linux@roeck-us.net>
56	
57	
58	Description
59	-----------
60	
61	This driver implements support for JEDEC JC 42.4 compliant temperature sensors,
62	which are used on many DDR3 memory modules for mobile devices and servers. Some
63	systems use the sensor to prevent memory overheating by automatically throttling
64	the memory controller.
65	
66	The driver auto-detects the chips listed above, but can be manually instantiated
67	to support other JC 42.4 compliant chips.
68	
69	Example: the following will load the driver for a generic JC 42.4 compliant
70	temperature 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	
75	A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
76	and critical temperature can be configured. There are alarms for high, low,
77	and critical thresholds.
78	
79	There is also an hysteresis to control the thresholds for resetting alarms.
80	Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
81	3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
82	limits. The chip supports only a single register to configure the hysteresis,
83	which applies to all limits. This register can be written by writing into
84	temp1_crit_hyst. Other hysteresis attributes are read-only.
85	
86	If the BIOS has configured the sensor for automatic temperature management, it
87	is likely that it has locked the registers, i.e., that the temperature limits
88	cannot be changed.
89	
90	Sysfs entries
91	-------------
92	
93	temp1_input		Temperature (RO)
94	temp1_min		Minimum temperature (RO or RW)
95	temp1_max		Maximum temperature (RO or RW)
96	temp1_crit		Critical high temperature (RO or RW)
97	
98	temp1_crit_hyst		Critical hysteresis temperature (RO or RW)
99	temp1_max_hyst		Maximum hysteresis temperature (RO)
100	
101	temp1_min_alarm		Temperature low alarm
102	temp1_max_alarm		Temperature high alarm
103	temp1_crit_alarm	Temperature critical alarm
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