drivers: led: pca9533: fix ms_to_psc wrap-around #100194
Open
+2
−2
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
If `period_ms` is 3 or less `tmp` is 0. Since `tmp` is type `uint32` subtracting 1 from 0 will wrap around to `UINT32_MAX` and is then clamped to `UINT8_MAX`. Fix the issue by changing `tmp` and `1` to signed types. Signed-off-by: Jeppe Odgaard <jeppe.odgaard@prevas.dk>
jeppenodgaard
force-pushed
the
fix-led-pca9533-wrap-around
branch
from
de5ff71 to
fe1c4cf
Compare
|
simonguinot
requested review from
fabiobaltieri,
kartben,
soburi and
thedjnK
fabiobaltieri
approved these changes
Nov 28, 2025
kartben
approved these changes
Nov 28, 2025
thedjnK
approved these changes
Nov 29, 2025
| static uint8_t ms_to_psc(uint32_t period_ms) | ||
| { | ||
| uint32_t tmp = (period_ms * 152U + 500U) / 1000U; | ||
| int32_t tmp = (period_ms * 152U + 500U) / 1000U; |
Contributor
There was a problem hiding this comment.
should probably have
int32_t tmp = (int32_t)((period_ms * 152U + 500U) / 1000U);
or will get a future warning on type assignment
Author
There was a problem hiding this comment.
I am not familiar with the warning.
Can you share a link please?
Author
There was a problem hiding this comment.
I am not familiar with the warning.
Can you share a link please?
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
6 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
If
period_msis 3 or lesstmpis 0. Sincetmpis typeuint32subtracting 1 from 0 will wrap around toUINT32_MAXand is then clamped toUINT8_MAX.Fix the issue by changing
tmpand1to signed types.Fixes #100020