sonic-net / sonic-net/sonic-linux-kernel
Problems encountered by tmp401 drivers
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Description
Code Path:drivers/hwmon/tmp401.c
Issue:We used the TMP411 temperature sensor chip, which occasionally read the Issue of abnormal temperature values (255.2℃).
Regarding this issue, our solution is:
Issue reason:The TMP411 temperature reading exception is caused by the timeout mechanism of TMP411.
The following content is excerpted from the TMP411 data sheet
TIMEOUT FUNCTION
When bit 7 of the Consecutive Alert Register is set high,the TMP411 timeout function is enabled. The TMP411resets the serial interface if either SCL or SDA are held lowfor 30ms (typical) between a START and STOP condition.If the TMP411 is holding the bus low, it releases the busand waits for a START condition. To avoid activating thetimeout function, it is necessary to maintain acommunication speed of at least 1kHz for the SCLoperating frequency. The default state of the timeoutfunction is enabled (bit 7 = high).
At present, this issue can be resolved by modifying the driver and disabling the timeout mechanism of TMP411 when driving probe.
Contributor guide
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First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with drivers/hwmon/tmp401.c and trace the probe path for TMP411 initialization, using the issue's timeout-function excerpt as context. Confirm how the timeout mechanism is configured during probing and verify that the reported abnormal temperature condition is addressed without affecting other supported sensors.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c, linux
- Domain
- embedded-iot, operating-systems
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100