From fda6e0034e9da64e1cec31f4539b6c7abd9ed8be Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Sat, 5 Apr 2025 11:27:13 +0200 Subject: [PATCH] pwm: stm32: Search an appropriate duty_cycle if period cannot be modified MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit If another channel is already enabled period must not be modified. If the requested period is smaller than this unchangable period the driver is still supposed to search a duty_cycle according to the usual rounding rules. So don't set the duty_cycle to 0 but continue to determine an appropriate value for ccr. Fixes: deaba9cff809 ("pwm: stm32: Implementation of the waveform callbacks") Signed-off-by: Uwe Kleine-König Link: https://lore.kernel.org/r/f0c50df31daa3d6069bfa8d7fb3e71fae241b026.1743844730.git.u.kleine-koenig@baylibre.com Signed-off-by: Uwe Kleine-König --- drivers/pwm/pwm-stm32.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-) diff --git a/drivers/pwm/pwm-stm32.c b/drivers/pwm/pwm-stm32.c index a59de4de18b6e..ec2c05c9ee7a6 100644 --- a/drivers/pwm/pwm-stm32.c +++ b/drivers/pwm/pwm-stm32.c @@ -103,22 +103,16 @@ static int stm32_pwm_round_waveform_tohw(struct pwm_chip *chip, if (ret) goto out; - /* - * calculate the best value for ARR for the given PSC, refuse if - * the resulting period gets bigger than the requested one. - */ arr = mul_u64_u64_div_u64(wf->period_length_ns, rate, (u64)NSEC_PER_SEC * (wfhw->psc + 1)); if (arr <= wfhw->arr) { /* - * requested period is small than the currently + * requested period is smaller than the currently * configured and unchangable period, report back the smallest - * possible period, i.e. the current state; Initialize - * ccr to anything valid. + * possible period, i.e. the current state and return 1 + * to indicate the wrong rounding direction. */ - wfhw->ccr = 0; ret = 1; - goto out; } } else {