From e45a178e9e285c86265611a56705a1e6444037e3 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= Date: Thu, 1 Jul 2021 09:29:27 +0200 Subject: [PATCH] pwm: Restore initial state if a legacy callback fails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit It is not entirely accurate to go back to the initial state after e.g. .enable() failed, as .config() still modified the hardware, but this same inconsistency exists for drivers that implement .apply(). Signed-off-by: Uwe Kleine-König Signed-off-by: Thierry Reding --- drivers/pwm/core.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index dedf38a81bf9..57b8cedfec3f 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -526,10 +526,8 @@ static int pwm_apply_legacy(struct pwm_chip *chip, struct pwm_device *pwm, const struct pwm_state *state) { int err; + struct pwm_state initial_state = pwm->state; - /* - * FIXME: restore the initial state in case of error. - */ if (state->polarity != pwm->state.polarity) { if (!chip->ops->set_polarity) return -EINVAL; @@ -550,7 +548,7 @@ static int pwm_apply_legacy(struct pwm_chip *chip, struct pwm_device *pwm, err = chip->ops->set_polarity(chip, pwm, state->polarity); if (err) - return err; + goto rollback; pwm->state.polarity = state->polarity; } @@ -573,7 +571,7 @@ static int pwm_apply_legacy(struct pwm_chip *chip, struct pwm_device *pwm, state->duty_cycle, state->period); if (err) - return err; + goto rollback; pwm->state.period = state->period; pwm->state.duty_cycle = state->duty_cycle; @@ -581,10 +579,14 @@ static int pwm_apply_legacy(struct pwm_chip *chip, struct pwm_device *pwm, if (!pwm->state.enabled) { err = chip->ops->enable(chip, pwm); if (err) - return err; + goto rollback; } return 0; + +rollback: + pwm->state = initial_state; + return err; } /**