diff options
Diffstat (limited to 'drivers/pwm/core.c')
| -rw-r--r-- | drivers/pwm/core.c | 40 |
1 files changed, 24 insertions, 16 deletions
diff --git a/drivers/pwm/core.c b/drivers/pwm/core.c index 8edfac17364e..6ad51aa60c03 100644 --- a/drivers/pwm/core.c +++ b/drivers/pwm/core.c @@ -448,36 +448,44 @@ EXPORT_SYMBOL_GPL(pwm_free); /** * pwm_apply_state() - atomically apply a new state to a PWM device * @pwm: PWM device - * @state: new state to apply. This can be adjusted by the PWM driver - * if the requested config is not achievable, for example, - * ->duty_cycle and ->period might be approximated. + * @state: new state to apply */ -int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) +int pwm_apply_state(struct pwm_device *pwm, const struct pwm_state *state) { + struct pwm_chip *chip; int err; if (!pwm || !state || !state->period || state->duty_cycle > state->period) return -EINVAL; + chip = pwm->chip; + 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) { - err = pwm->chip->ops->apply(pwm->chip, pwm, state); + if (chip->ops->apply) { + err = chip->ops->apply(chip, pwm, state); if (err) return err; - pwm->state = *state; + /* + * .apply might have to round some values in *state, if possible + * read the actually implemented value back. + */ + if (chip->ops->get_state) + chip->ops->get_state(chip, pwm, &pwm->state); + else + pwm->state = *state; } else { /* * FIXME: restore the initial state in case of error. */ if (state->polarity != pwm->state.polarity) { - if (!pwm->chip->ops->set_polarity) + if (!chip->ops->set_polarity) return -ENOTSUPP; /* @@ -486,12 +494,12 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) * ->apply(). */ if (pwm->state.enabled) { - pwm->chip->ops->disable(pwm->chip, pwm); + chip->ops->disable(chip, pwm); pwm->state.enabled = false; } - err = pwm->chip->ops->set_polarity(pwm->chip, pwm, - state->polarity); + err = chip->ops->set_polarity(chip, pwm, + state->polarity); if (err) return err; @@ -500,9 +508,9 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) if (state->period != pwm->state.period || state->duty_cycle != pwm->state.duty_cycle) { - err = pwm->chip->ops->config(pwm->chip, pwm, - state->duty_cycle, - state->period); + err = chip->ops->config(pwm->chip, pwm, + state->duty_cycle, + state->period); if (err) return err; @@ -512,11 +520,11 @@ int pwm_apply_state(struct pwm_device *pwm, struct pwm_state *state) if (state->enabled != pwm->state.enabled) { if (state->enabled) { - err = pwm->chip->ops->enable(pwm->chip, pwm); + err = chip->ops->enable(chip, pwm); if (err) return err; } else { - pwm->chip->ops->disable(pwm->chip, pwm); + chip->ops->disable(chip, pwm); } pwm->state.enabled = state->enabled; |