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author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 19:56:51 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-05-06 19:56:51 -0700 |
commit | 7aefd944f038c7469571adb37769cb6f3924ecfa (patch) | |
tree | f0a8dc23633b6bbbc4f0bff932f332e847fb6c1b /Documentation/hwmon/lm77.rst | |
parent | Merge branch 'ras-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip (diff) | |
parent | hwmon: (lm75) Add support for TMP75B (diff) | |
download | linux-dev-7aefd944f038c7469571adb37769cb6f3924ecfa.tar.xz linux-dev-7aefd944f038c7469571adb37769cb6f3924ecfa.zip |
Merge tag 'hwmon-for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon updates from Guenter Roeck:
- Add driver for Intersil ISL68137 PWM Controller
- Add driver for Lochnagar 2
- Add driver for Infineon IR38064 Voltage Regulator
- Add support for TMP75B to lm75 driver
- Convert documentation to ReST format
- Use request_muxed_region for Super-IO accesses in several drivers
- Add 'samples' attribute to ABI, and start using it
- Add support for custom sysfs attributes to pmbus drivers (used in
ISL68137 driver)
- Introduce HWMON_CHANNEL_INFO macro
- Automated changes:
- Use permission specific [SENSOR_][DEVICE_]ATTR variants
- Fix build warnings due to unused of_device_id structures
- Use HWMON_CHANNEL_INFO macro
- Various minor improvements and fixes
* tag 'hwmon-for-v5.2' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging: (125 commits)
hwmon: (lm75) Add support for TMP75B
dt-bindings: hwmon: Add tmp75b to lm75.txt
hwmon: (s3c) Use dev_get_drvdata()
hwmon: (max6650) Drop call to thermal_cdev_update
docs: hwmon: remove the extension from .rst files
docs: hwmon: convert three docs to ReST format
hwmon: (max6650) add thermal cooling device capability
hwmon: (ina3221) Add voltage conversion time settings
hwmon: (ina3221) Do not read-back to cache reg_config
docs: hwmon: Add an index file and rename docs to *.rst
docs: hwmon: convert remaining files to ReST format
docs: hwmon: misc files: convert to ReST format
docs: hwmon: pmbus files: convert to ReST format
docs: hwmon: k8temp, w83793: convert to ReST format
docs: hwmon: da9052, da9055: convert to ReST format
docs: hwmon: wm831x, wm8350: convert to ReST format
docs: hwmon: dme1737, vt1211: convert to ReST format
docs: hwmon: ads1015: convert to ReST format
docs: hwmon: asc7621: convert to ReST format
docs: hwmon: ibmpowernv: convert to ReST format
...
Diffstat (limited to 'Documentation/hwmon/lm77.rst')
-rw-r--r-- | Documentation/hwmon/lm77.rst | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/Documentation/hwmon/lm77.rst b/Documentation/hwmon/lm77.rst new file mode 100644 index 000000000000..4ed3fe6b999a --- /dev/null +++ b/Documentation/hwmon/lm77.rst @@ -0,0 +1,45 @@ +Kernel driver lm77 +================== + +Supported chips: + + * National Semiconductor LM77 + + Prefix: 'lm77' + + Addresses scanned: I2C 0x48 - 0x4b + + Datasheet: Publicly available at the National Semiconductor website + + http://www.national.com/ + + +Author: Andras BALI <drewie@freemail.hu> + +Description +----------- + +The LM77 implements one temperature sensor. The temperature +sensor incorporates a band-gap type temperature sensor, +10-bit ADC, and a digital comparator with user-programmable upper +and lower limit values. + +The LM77 implements 3 limits: low (temp1_min), high (temp1_max) and +critical (temp1_crit.) It also implements an hysteresis mechanism which +applies to all 3 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 3 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. +* All 3 hysteresis can't be set independently. We decided to make + temp1_crit_hyst writable, while temp1_min_hyst and temp1_max_hyst 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 the low and high limits. +* The limits should be set before the hysteresis. |