summaryrefslogtreecommitdiff
path: root/Documentation/hwmon/emc1403
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2014-06-03 22:09:43 +0400
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-03 22:09:43 +0400
commitf456205265a61f1d649f8378eceaa163850cba4e (patch)
treec974aafac8fad9bf1322f2ec66aaf01d01adfaf8 /Documentation/hwmon/emc1403
parent8f5759aeb88a47448cd92ab55a016d013b154a98 (diff)
parent9d311eddf3565ed0e05b3cb5a22db41fa74d9d86 (diff)
downloadlinux-f456205265a61f1d649f8378eceaa163850cba4e.tar.xz
Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging into next
Pull hwmon updates from Guenter Roeck: "New driver for NCT6683D New chip support to existing drivers: - add support for STTS2004 and AT30TSE004 to jc42 driver - add support for EMC1402/EMC1412/EMC1422 to emc1403 driver Other notable changes: - document hwmon kernel API - convert jc42, lm70, lm75, lm77, lm83, lm92, max1619, tmp421, and tmp102 drivers to use new hwmon API functions - replace function macros in lm80, lm92, and jc42 drivers with real code - convert emc1403 driver to use regmap, add support for additional attributes, and add device IDs for EMC1412, EMC1413, and EMC1414 - various additional cleanup and minor bug fixes in several drivers" * tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: (60 commits) hwmon: (nct6775) Fix probe unwind paths to properly unregister platform devices hwmon: (nct6683) Fix probe unwind paths to properly unregister platform devices hwmon: (ultra45_env) Introduce managed version of kzalloc hwmon: Driver for NCT6683D hwmon: (lm80) Rearrange code to avoid forward declarations hwmon: (lm80) Convert fan display function macros into functions hwmon: (lm80) Convert voltage display function macros into functions hwmon: (lm80) Convert temperature display function macros into functions hwmon: (lm80) Normalize all temperature values to 16 bit hwmon: (lm80) Simplify TEMP_FROM_REG hwmon: (lm83) Convert to use devm_hwmon_device_register_with_groups hwmon: (lm83) Rearange code to avoid forward declarations hwmon: (lm83) Drop FSF address hwmon: (max1619) Convert to use devm_hwmon_device_register_with_groups hwmon: (max1619) Drop function macros hwmon: (max1619) Rearrange code to avoid forward declarations hwmon: (max1619) Drop FSF address hwmon: (max1619) Fix critical alarm display hwmon: (jc42) Add support for STTS2004 and AT30TSE004 hwmon: (jc42) Convert function macros into functions ...
Diffstat (limited to 'Documentation/hwmon/emc1403')
-rw-r--r--Documentation/hwmon/emc140359
1 files changed, 59 insertions, 0 deletions
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.