LXR linux/Documentation/hwmon/jc42.rst

   1Kernel driver jc42
   2==================
   3
   4Supported chips:
   5
   6  * Analog Devices ADT7408
   7
   8    Datasheets:
   9
  10        https://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf
  11
  12  * Atmel AT30TS00, AT30TS002A/B, AT30TSE004A
  13
  14    Datasheets:
  15
  16        http://www.atmel.com/Images/doc8585.pdf
  17
  18        http://www.atmel.com/Images/doc8711.pdf
  19
  20        http://www.atmel.com/Images/Atmel-8852-SEEPROM-AT30TSE002A-Datasheet.pdf
  21
  22        http://www.atmel.com/Images/Atmel-8868-DTS-AT30TSE004A-Datasheet.pdf
  23
  24  * IDT TSE2002B3, TSE2002GB2, TSE2004GB2, TS3000B3, TS3000GB0, TS3000GB2,
  25
  26        TS3001GB2
  27
  28    Datasheets:
  29
  30        Available from IDT web site
  31
  32  * Maxim MAX6604
  33
  34    Datasheets:
  35
  36        http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
  37
  38  * Microchip MCP9804, MCP9805, MCP9808, MCP98242, MCP98243, MCP98244, MCP9843
  39
  40    Datasheets:
  41
  42        https://ww1.microchip.com/downloads/en/DeviceDoc/22203C.pdf
  43
  44        https://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf
  45
  46        https://ww1.microchip.com/downloads/en/DeviceDoc/25095A.pdf
  47
  48        https://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf
  49
  50        https://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf
  51
  52        https://ww1.microchip.com/downloads/en/DeviceDoc/22327A.pdf
  53
  54  * NXP Semiconductors SE97, SE97B, SE98, SE98A
  55
  56    Datasheets:
  57
  58        https://www.nxp.com/documents/data_sheet/SE97.pdf
  59
  60        https://www.nxp.com/documents/data_sheet/SE97B.pdf
  61
  62        https://www.nxp.com/documents/data_sheet/SE98.pdf
  63
  64        https://www.nxp.com/documents/data_sheet/SE98A.pdf
  65
  66  * ON Semiconductor CAT34TS02, CAT6095
  67
  68    Datasheet:
  69
  70        https://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
  71
  72        https://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
  73
  74  * ST Microelectronics STTS424, STTS424E02, STTS2002, STTS2004, STTS3000
  75
  76    Datasheets:
  77
  78        http://www.st.com/web/en/resource/technical/document/datasheet/CD00157556.pdf
  79
  80        http://www.st.com/web/en/resource/technical/document/datasheet/CD00157558.pdf
  81
  82        http://www.st.com/web/en/resource/technical/document/datasheet/CD00266638.pdf
  83
  84        http://www.st.com/web/en/resource/technical/document/datasheet/CD00225278.pdf
  85
  86        http://www.st.com/web/en/resource/technical/document/datasheet/DM00076709.pdf
  87
  88  * JEDEC JC 42.4 compliant temperature sensor chips
  89
  90    Datasheet:
  91
  92        http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf
  93
  94
  95  Common for all chips:
  96
  97    Prefix: 'jc42'
  98
  99    Addresses scanned: I2C 0x18 - 0x1f
 100
 101Author:
 102        Guenter Roeck <linux@roeck-us.net>
 103
 104
 105Description
 106-----------
 107
 108This driver implements support for JEDEC JC 42.4 compliant temperature sensors,
 109which are used on many DDR3 memory modules for mobile devices and servers. Some
 110systems use the sensor to prevent memory overheating by automatically throttling
 111the memory controller.
 112
 113The driver auto-detects the chips listed above, but can be manually instantiated
 114to support other JC 42.4 compliant chips.
 115
 116Example: the following will load the driver for a generic JC 42.4 compliant
 117temperature sensor at address 0x18 on I2C bus #1::
 118
 119        # modprobe jc42
 120        # echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device
 121
 122A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
 123and critical temperature can be configured. There are alarms for high, low,
 124and critical thresholds.
 125
 126There is also an hysteresis to control the thresholds for resetting alarms.
 127Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
 1283.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
 129limits. The chip supports only a single register to configure the hysteresis,
 130which applies to all limits. This register can be written by writing into
 131temp1_crit_hyst. Other hysteresis attributes are read-only.
 132
 133If the BIOS has configured the sensor for automatic temperature management, it
 134is likely that it has locked the registers, i.e., that the temperature limits
 135cannot be changed.
 136
 137Sysfs entries
 138-------------
 139
 140======================= ===========================================
 141temp1_input             Temperature (RO)
 142temp1_min               Minimum temperature (RO or RW)
 143temp1_max               Maximum temperature (RO or RW)
 144temp1_crit              Critical high temperature (RO or RW)
 145
 146temp1_crit_hyst         Critical hysteresis temperature (RO or RW)
 147temp1_max_hyst          Maximum hysteresis temperature (RO)
 148
 149temp1_min_alarm         Temperature low alarm
 150temp1_max_alarm         Temperature high alarm
 151temp1_crit_alarm        Temperature critical alarm
 152======================= ===========================================
 153