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| author | Nylon Chen <[email protected]> | 2025-05-29 03:53:41 +0000 |
|---|---|---|
| committer | Uwe Kleine-König <[email protected]> | 2025-07-07 06:39:34 +0000 |
| commit | 6df3aac763fa995260ab0545c1e54f0c21b2feb8 (patch) | |
| tree | 53f814139e0f97136b54f6b5d70dc1f6d5c09ed3 /drivers/pwm/pwm-stm32.c | |
| parent | pwm: sifive: Fix PWM algorithm and clarify inverted compare behavior (diff) | |
| download | kernel-6df3aac763fa995260ab0545c1e54f0c21b2feb8.tar.gz kernel-6df3aac763fa995260ab0545c1e54f0c21b2feb8.zip | |
pwm: sifive: Fix rounding and idempotency issues in apply and get_state
This fix ensures consistent rounding and avoids mismatches
between applied and reported PWM values that could trigger false
idempotency failures in debug checks
This change ensures:
- real_period is now calculated using DIV_ROUND_UP_ULL() to avoid underestimation.
- duty_cycle is rounded up to match the fractional computation in apply()
- apply() truncates the result to compensate for get_state's rounding up logic
These fixes resolve issues like:
.apply is supposed to round down duty_cycle (requested: 360/504000, applied: 361/504124)
.apply is not idempotent (ena=1 pol=0 1739692/4032985) -> (ena=1 pol=0 1739630/4032985)
Reported-by: kernel test robot <[email protected]>
Closes: https://lore.kernel.org/oe-kbuild-all/[email protected]/
Co-developed-by: Zong Li <[email protected]>
Signed-off-by: Zong Li <[email protected]>
Signed-off-by: Nylon Chen <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Uwe Kleine-König <[email protected]>
Diffstat (limited to 'drivers/pwm/pwm-stm32.c')
0 files changed, 0 insertions, 0 deletions