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Diffstat (limited to 'kernel/Documentation/hwmon/adm1021')
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diff --git a/kernel/Documentation/hwmon/adm1021 b/kernel/Documentation/hwmon/adm1021 new file mode 100644 index 000000000..02ad96cf9 --- /dev/null +++ b/kernel/Documentation/hwmon/adm1021 @@ -0,0 +1,113 @@ +Kernel driver adm1021 +===================== + +Supported chips: + * Analog Devices ADM1021 + Prefix: 'adm1021' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the Analog Devices website + * Analog Devices ADM1021A/ADM1023 + Prefix: 'adm1023' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the Analog Devices website + * Genesys Logic GL523SM + Prefix: 'gl523sm' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: + * Maxim MAX1617 + Prefix: 'max1617' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the Maxim website + * Maxim MAX1617A + Prefix: 'max1617a' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the Maxim website + * National Semiconductor LM84 + Prefix: 'lm84' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the National Semiconductor website + * Philips NE1617 + Prefix: 'max1617' (probably detected as a max1617) + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the Philips website + * Philips NE1617A + Prefix: 'max1617' (probably detected as a max1617) + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the Philips website + * TI THMC10 + Prefix: 'thmc10' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the TI website + * Onsemi MC1066 + Prefix: 'mc1066' + Addresses scanned: I2C 0x18 - 0x1a, 0x29 - 0x2b, 0x4c - 0x4e + Datasheet: Publicly available at the Onsemi website + + +Authors: + Frodo Looijaard <frodol@dds.nl>, + Philip Edelbrock <phil@netroedge.com> + +Module Parameters +----------------- + +* read_only: int + Don't set any values, read only mode + + +Description +----------- + +The chips supported by this driver are very similar. The Maxim MAX1617 is +the oldest; it has the problem that it is not very well detectable. The +MAX1617A solves that. The ADM1021 is a straight clone of the MAX1617A. +Ditto for the THMC10. From here on, we will refer to all these chips as +ADM1021-clones. + +The ADM1021 and MAX1617A reports a die code, which is a sort of revision +code. This can help us pinpoint problems; it is not very useful +otherwise. + +ADM1021-clones implement two temperature sensors. One of them is internal, +and measures the temperature of the chip itself; the other is external and +is realised in the form of a transistor-like device. A special alarm +indicates whether the remote sensor is connected. + +Each sensor has its own low and high limits. When they are crossed, the +corresponding alarm is set and remains on as long as the temperature stays +out of range. Temperatures are measured in degrees Celsius. Measurements +are possible between -65 and +127 degrees, with a resolution of one degree. + +If an alarm triggers, it will remain triggered until the hardware register +is read at least once. This means that the cause for the alarm may already +have disappeared! + +This driver only updates its values each 1.5 seconds; reading it more often +will do no harm, but will return 'old' values. It is possible to make +ADM1021-clones do faster measurements, but there is really no good reason +for that. + + +Netburst-based Xeon support +--------------------------- + +Some Xeon processors based on the Netburst (early Pentium 4, from 2001 to +2003) microarchitecture had real MAX1617, ADM1021, or compatible chips +within them, with two temperature sensors. Other Xeon processors of this +era (with 400 MHz FSB) had chips with only one temperature sensor. + +If you have such an old Xeon, and you get two valid temperatures when +loading the adm1021 module, then things are good. + +If nothing happens when loading the adm1021 module, and you are certain +that your specific Xeon processor model includes compatible sensors, you +will have to explicitly instantiate the sensor chips from user-space. See +method 4 in Documentation/i2c/instantiating-devices. Possible slave +addresses are 0x18, 0x1a, 0x29, 0x2b, 0x4c, or 0x4e. It is likely that +only temp2 will be correct and temp1 will have to be ignored. + +Previous generations of the Xeon processor (based on Pentium II/III) +didn't have these sensors. Next generations of Xeon processors (533 MHz +FSB and faster) lost them, until the Core-based generation which +introduced integrated digital thermal sensors. These are supported by +the coretemp driver. |