| 1 | Kernel driver jc42 |
| 2 | ================== |
| 3 | |
| 4 | Supported 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 | |
| 101 | Author: |
| 102 | Guenter Roeck <linux@roeck-us.net> |
| 103 | |
| 104 | |
| 105 | Description |
| 106 | ----------- |
| 107 | |
| 108 | This driver implements support for JEDEC JC 42.4 compliant temperature sensors, |
| 109 | which are used on many DDR3 memory modules for mobile devices and servers. Some |
| 110 | systems use the sensor to prevent memory overheating by automatically throttling |
| 111 | the memory controller. |
| 112 | |
| 113 | The driver auto-detects the chips listed above, but can be manually instantiated |
| 114 | to support other JC 42.4 compliant chips. |
| 115 | |
| 116 | Example: the following will load the driver for a generic JC 42.4 compliant |
| 117 | temperature 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 | |
| 122 | A JC 42.4 compliant chip supports a single temperature sensor. Minimum, maximum, |
| 123 | and critical temperature can be configured. There are alarms for high, low, |
| 124 | and critical thresholds. |
| 125 | |
| 126 | There is also an hysteresis to control the thresholds for resetting alarms. |
| 127 | Per JC 42.4 specification, the hysteresis threshold can be configured to 0, 1.5, |
| 128 | 3.0, and 6.0 degrees C. Configured hysteresis values will be rounded to those |
| 129 | limits. The chip supports only a single register to configure the hysteresis, |
| 130 | which applies to all limits. This register can be written by writing into |
| 131 | temp1_crit_hyst. Other hysteresis attributes are read-only. |
| 132 | |
| 133 | If the BIOS has configured the sensor for automatic temperature management, it |
| 134 | is likely that it has locked the registers, i.e., that the temperature limits |
| 135 | cannot be changed. |
| 136 | |
| 137 | Sysfs entries |
| 138 | ------------- |
| 139 | |
| 140 | ======================= =========================================== |
| 141 | temp1_input Temperature (RO) |
| 142 | temp1_min Minimum temperature (RO or RW) |
| 143 | temp1_max Maximum temperature (RO or RW) |
| 144 | temp1_crit Critical high temperature (RO or RW) |
| 145 | |
| 146 | temp1_crit_hyst Critical hysteresis temperature (RO or RW) |
| 147 | temp1_max_hyst Maximum hysteresis temperature (RO) |
| 148 | |
| 149 | temp1_min_alarm Temperature low alarm |
| 150 | temp1_max_alarm Temperature high alarm |
| 151 | temp1_crit_alarm Temperature critical alarm |
| 152 | ======================= =========================================== |