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diff --git a/Documentation/hwmon/emc1403 b/Documentation/hwmon/emc1403 new file mode 100644 index 000000000000..a869b0ef6a9d --- /dev/null +++ b/Documentation/hwmon/emc1403 @@ -0,0 +1,59 @@ +Kernel driver emc1403 +===================== + +Supported chips: + * SMSC / Microchip EMC1402, EMC1412 + Addresses scanned: I2C 0x18, 0x1c, 0x29, 0x4c, 0x4d, 0x5c + Prefix: 'emc1402' + Datasheets: + http://ww1.microchip.com/downloads/en/DeviceDoc/1412.pdf + http://ww1.microchip.com/downloads/en/DeviceDoc/1402.pdf + * SMSC / Microchip EMC1403, EMC1404, EMC1413, EMC1414 + Addresses scanned: I2C 0x18, 0x29, 0x4c, 0x4d + Prefix: 'emc1403', 'emc1404' + Datasheets: + http://ww1.microchip.com/downloads/en/DeviceDoc/1403_1404.pdf + http://ww1.microchip.com/downloads/en/DeviceDoc/1413_1414.pdf + * SMSC / Microchip EMC1422 + Addresses scanned: I2C 0x4c + Prefix: 'emc1422' + Datasheet: + http://ww1.microchip.com/downloads/en/DeviceDoc/1422.pdf + * SMSC / Microchip EMC1423, EMC1424 + Addresses scanned: I2C 0x4c + Prefix: 'emc1423', 'emc1424' + Datasheet: + http://ww1.microchip.com/downloads/en/DeviceDoc/1423_1424.pdf + +Author: + Kalhan Trisal <kalhan.trisal@intel.com + + +Description +----------- + +The Standard Microsystems Corporation (SMSC) / Microchip EMC14xx chips +contain up to four temperature sensors. EMC14x2 support two sensors +(one internal, one external). EMC14x3 support three sensors (one internal, +two external), and EMC14x4 support four sensors (one internal, three +external). + +The chips implement three limits for each sensor: low (tempX_min), high +(tempX_max) and critical (tempX_crit.) The chips also implement an +hysteresis mechanism which applies to all limits. The relative difference +is stored in a single register on the chip, which means that the relative +difference between the limit and its hysteresis is always the same for +all three limits. + +This implementation detail implies the following: +* When setting a limit, its hysteresis will automatically follow, the + difference staying unchanged. For example, if the old critical limit + was 80 degrees C, and the hysteresis was 75 degrees C, and you change + the critical limit to 90 degrees C, then the hysteresis will + automatically change to 85 degrees C. +* The hysteresis values can't be set independently. We decided to make + only temp1_crit_hyst writable, while all other hysteresis attributes + are read-only. Setting temp1_crit_hyst writes the difference between + temp1_crit_hyst and temp1_crit into the chip, and the same relative + hysteresis applies automatically to all other limits. +* The limits should be set before the hysteresis. |