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pwm: Don't use memcmp() to compare state variables

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Given that struct pwm_state is sparse (at least on some platforms),
variables of this type might represent the same state because all fields
are pairwise identical but still memcmp() returns a difference because
some of the unused bits are different.

To prevent surprises compare member by member instead of the whole
occupied memory.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Thierry Reding <thierry.reding@gmail.com>
This commit is contained in:
Uwe Kleine-König 2019-01-07 20:49:37 +01:00 committed by Thierry Reding
parent bfeffd1552
commit 309b32fb97
1 changed files with 4 additions and 1 deletions
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5
drivers/pwm/core.c
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@ -472,7 +472,10 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state)
state->duty_cycle > state->period)
return -EINVAL;
if (!memcmp(state, &pwm->state, sizeof(*state)))
if (state->period == pwm->state.period &&
state->duty_cycle == pwm->state.duty_cycle &&
state->polarity == pwm->state.polarity &&
state->enabled == pwm->state.enabled)
return 0;
if (pwm->chip->ops->apply) {