Hello Sean,
On Tue, Dec 12, 2023 at 08:34:03AM +0000, Sean Young wrote:
> +/**
> + * pwm_apply_might_sleep() - atomically apply a new state to a PWM device
> + * Cannot be used in atomic context.
> + * @pwm: PWM device
> + * @state: new state to apply
> + */
> +int pwm_apply_might_sleep(struct pwm_device *pwm, const struct pwm_state *state)
> +{
> + int err;
> +
> + /*
> + * Some lowlevel driver's implementations of .apply() make use of
> + * mutexes, also with some drivers only returning when the new
> + * configuration is active calling pwm_apply_might_sleep() from atomic context
> + * is a bad idea. So make it explicit that calling this function might
> + * sleep.
> + */
> + might_sleep();
> +
> + if (IS_ENABLED(CONFIG_PWM_DEBUG) && pwm->chip->atomic) {
> + /*
> + * Catch any drivers that have been marked as atomic but
> + * that will sleep anyway.
> + */
> + non_block_start();
> + err = pwm_apply_unchecked(pwm, state);
> + non_block_end();
> + } else {
> + err = pwm_apply_unchecked(pwm, state);
> + }
> +
> /*
> * only do this after pwm->state was applied as some
> * implementations of .get_state depend on this
> */
> - pwm_apply_debug(pwm, state);
> + if (!err)
> + pwm_apply_debug(pwm, state);
It's easier to keep that in pwm_apply_unchecked(), isn't it? Then
pwm_apply_atomic() also benefits from the checks.
I'm not so happy with the function name of pwm_apply_unchecked(), but I
don't have a good suggestion either. Probably I'd have chosen
__pam_apply(), but that's probably subjective.
Best regards
Uwe
--
Pengutronix e.K. | Uwe Kleine-König |
Industrial Linux Solutions | https://www.pengutronix.de/ |
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