Documentation/hwmon/jc42

   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