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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-05-06 01:02:30 +0000
commit76cb841cb886eef6b3bee341a2266c76578724ad (patch)
treef5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /Documentation/hwmon/emc1403
parentInitial commit. (diff)
downloadlinux-upstream/4.19.249.tar.xz
linux-upstream/4.19.249.zip
Adding upstream version 4.19.249.upstream/4.19.249upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+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.