Documentation/hwmon/jc42

   1 Kernel driver jc42
   2 ==================
   3
   4 Supported chips:
   5   * Analog Devices ADT7408
   6     Prefix: 'adt7408'
   7     Addresses scanned: I2C 0x18 - 0x1f
   8     Datasheets:
   9         http://www.analog.com/static/imported-files/data_sheets/ADT7408.pdf
  10   * IDT TSE2002B3, TS3000B3
  11     Prefix: 'tse2002b3', 'ts3000b3'
  12     Addresses scanned: I2C 0x18 - 0x1f
  13     Datasheets:
  14         http://www.idt.com/products/getdoc.cfm?docid=18715691
  15         http://www.idt.com/products/getdoc.cfm?docid=18715692
  16   * Maxim MAX6604
  17     Prefix: 'max6604'
  18     Addresses scanned: I2C 0x18 - 0x1f
  19     Datasheets:
  20         http://datasheets.maxim-ic.com/en/ds/MAX6604.pdf
  21   * Microchip MCP9805, MCP98242, MCP98243, MCP9843
  22     Prefixes: 'mcp9805', 'mcp98242', 'mcp98243', 'mcp9843'
  23     Addresses scanned: I2C 0x18 - 0x1f
  24     Datasheets:
  25         http://ww1.microchip.com/downloads/en/DeviceDoc/21977b.pdf
  26         http://ww1.microchip.com/downloads/en/DeviceDoc/21996a.pdf
  27         http://ww1.microchip.com/downloads/en/DeviceDoc/22153c.pdf
  28   * NXP Semiconductors SE97, SE97B
  29     Prefix: 'se97'
  30     Addresses scanned: I2C 0x18 - 0x1f
  31     Datasheets:
  32         http://www.nxp.com/documents/data_sheet/SE97.pdf
  33         http://www.nxp.com/documents/data_sheet/SE97B.pdf
  34   * NXP Semiconductors SE98
  35     Prefix: 'se98'
  36     Addresses scanned: I2C 0x18 - 0x1f
  37     Datasheets:
  38         http://www.nxp.com/documents/data_sheet/SE98.pdf
  39   * ON Semiconductor CAT34TS02, CAT6095
  40     Prefix: 'cat34ts02', 'cat6095'
  41     Addresses scanned: I2C 0x18 - 0x1f
  42     Datasheet:
  43         http://www.onsemi.com/pub_link/Collateral/CAT34TS02-D.PDF
  44         http://www.onsemi.com/pub/Collateral/CAT6095-D.PDF
  45   * ST Microelectronics STTS424, STTS424E02
  46     Prefix: 'stts424'
  47     Addresses scanned: I2C 0x18 - 0x1f
  48     Datasheets:
  49         http://www.st.com/stonline/products/literature/ds/13447/stts424.pdf
  50         http://www.st.com/stonline/products/literature/ds/13448/stts424e02.pdf
  51   * JEDEC JC 42.4 compliant temperature sensor chips
  52     Prefix: 'jc42'
  53     Addresses scanned: I2C 0x18 - 0x1f
  54     Datasheet:
  55         http://www.jedec.org/sites/default/files/docs/4_01_04R19.pdf
  56
  57 Author:
  58         Guenter Roeck <guenter.roeck@ericsson.com>
  59
  60
  61 Description
  62 -----------
  63
  64 This driver implements support for JEDEC JC 42.4 compliant temperature sensors,
  65 which are used on many DDR3 memory modules for mobile devices and servers. Some
  66 systems use the sensor to prevent memory overheating by automatically throttling
  67 the memory controller.
  68
  69 The driver auto-detects the chips listed above, but can be manually instantiated
  70 to support other JC 42.4 compliant chips.
  71
  72 Example: the following will load the driver for a generic JC 42.4 compliant
  73 temperature sensor at address 0x18 on I2C bus #1:
  74
  75 # modprobe jc42
  76 # echo jc42 0x18 > /sys/bus/i2c/devices/i2c-1/new_device
  77
  78 A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum,
  79 and critical temperature can be configured. There are alarms for high, low,
  80 and critical thresholds.
  81
  82 There is also an hysteresis to control the thresholds for resetting alarms.
  83 Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5,
  84 3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those
  85 limits. The chip supports only a single register to configure the hysteresis,
  86 which applies to all limits. This register can be written by writing into
  87 temp1_crit_hyst. Other hysteresis attributes are read-only.
  88
  89 If the BIOS has configured the sensor for automatic temperature management, it
  90 is likely that it has locked the registers, i.e., that the temperature limits
  91 cannot be changed.
  92
  93 Sysfs entries
  94 -------------
  95
  96 temp1_input             Temperature (RO)
  97 temp1_min               Minimum temperature (RO or RW)
  98 temp1_max               Maximum temperature (RO or RW)
  99 temp1_crit              Critical high temperature (RO or RW)
 100
 101 temp1_crit_hyst         Critical hysteresis temperature (RO or RW)
 102 temp1_max_hyst          Maximum hysteresis temperature (RO)
 103
 104 temp1_min_alarm         Temperature low alarm
 105 temp1_max_alarm         Temperature high alarm
 106 temp1_crit_alarm        Temperature critical alarm