Re: [PATCH v7 0/9] leds: st1202: fix multiple bugs in pattern engine and brightness handling

From: Manuel Fombuena

Date: Fri Jul 03 2026 - 07:28:20 EST



All Sashiko's comments on v7 are pre-existing issues outside the scope of
this series, with the exception of one comment each on Patch 4 and Patch
6. Unless there are any other reviewer comments, there will not be a v8.
The pre-existing issues will be addressed in a follow-up submission.

For the sake of clarity, these are the responses to the non-pre-existing
issues.

Patch 4 comment: after pattern_clear() sets all 8 PWM slots to FULL, a
shorter pattern programmed with len < 8 leaves the trailing slots at
100% duty cycle. If another channel runs an 8-step sequence, the
cleared channel flashes at maximum brightness during its unused steps.

Response: this is a consequence of the pre-existing issue where
st1202_led_pattern_set() does not zero trailing slots when
len < ST1202_MAX_PATTERNS. The root fix is outside the scope of this
series and will be addressed in a follow-up submission.

Patch 6 comment: the loop in st1202_brightness_set() ignores the
return value of st1202_pwm_pattern_write(), potentially continuing
writes after a bus failure.

Response: as noted in the response to the v6 review, this is
intentional. A transient I2C error on one slot does not guarantee
subsequent writes will also fail. Breaking early would leave remaining
PWM slots unwritten unnecessarily, putting the channel in a partially
updated state. brightness_set() is a void callback and cannot propagate
errors regardless, and st1202_write_reg() already logs each individual
failure via dev_err().

--
Manuel Fombuena