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pwm: Let pwm_set_waveform() succeed even if lowlevel driver rounded up

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Waveform parameters are supposed to be rounded down to the next value
possible for the hardware. However when a requested value is too small,
.round_waveform_tohw() is supposed to pick the next bigger value and
return 1. Let pwm_set_waveform() behave in the same way.

This creates consistency between pwm_set_waveform_might_sleep() with
exact=false and pwm_round_waveform_might_sleep() +
pwm_set_waveform_might_sleep() with exact=true.

The PWM_DEBUG rounding check has to be adapted to only trigger if no
uprounding happend.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Tested-by: Trevor Gamblin <tgamblin@baylibre.com>
Link: https://lore.kernel.org/r/353dc6ae31be815e41fd3df89c257127ca0d1a09.1743844730.git.u.kleine-koenig@baylibre.com
Signed-off-by: Uwe Kleine-König <ukleinek@kernel.org>
This commit is contained in:
Uwe Kleine-König 2025-04-05 11:27:12 +02:00 committed by Uwe Kleine-König
parent 928446a530
commit 00e53d0f4b
1 changed files with 7 additions and 6 deletions
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13
drivers/pwm/core.c
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@ -322,7 +322,7 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
const struct pwm_ops *ops = chip->ops;
char wfhw[WFHWSIZE];
struct pwm_waveform wf_rounded;
int err;
int err, ret_tohw;
BUG_ON(WFHWSIZE < ops->sizeof_wfhw);
@ -332,16 +332,16 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
if (!pwm_wf_valid(wf))
return -EINVAL;
err = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw);
if (err)
return err;
ret_tohw = __pwm_round_waveform_tohw(chip, pwm, wf, &wfhw);
if (ret_tohw < 0)
return ret_tohw;
if ((IS_ENABLED(CONFIG_PWM_DEBUG) || exact) && wf->period_length_ns) {
err = __pwm_round_waveform_fromhw(chip, pwm, &wfhw, &wf_rounded);
if (err)
return err;
if (IS_ENABLED(CONFIG_PWM_DEBUG) && !pwm_check_rounding(wf, &wf_rounded))
if (IS_ENABLED(CONFIG_PWM_DEBUG) && ret_tohw == 0 && !pwm_check_rounding(wf, &wf_rounded))
dev_err(&chip->dev, "Wrong rounding: requested %llu/%llu [+%llu], result %llu/%llu [+%llu]\n",
wf->duty_length_ns, wf->period_length_ns, wf->duty_offset_ns,
wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns);
@ -382,7 +382,8 @@ static int __pwm_set_waveform(struct pwm_device *pwm,
wf_rounded.duty_length_ns, wf_rounded.period_length_ns, wf_rounded.duty_offset_ns,
wf_set.duty_length_ns, wf_set.period_length_ns, wf_set.duty_offset_ns);
}
return 0;
return ret_tohw;
}
/**