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