static void pwm_apply_state_debug()

in core.c [450:549]

• 73 lines of code
• 30 McCabe index (conditional complexity)

static void pwm_apply_state_debug(struct pwm_device *pwm,
				  const struct pwm_state *state)
{
	struct pwm_state *last = &pwm->last;
	struct pwm_chip *chip = pwm->chip;
	struct pwm_state s1, s2;
	int err;

	if (!IS_ENABLED(CONFIG_PWM_DEBUG))
		return;

	/* No reasonable diagnosis possible without .get_state() */
	if (!chip->ops->get_state)
		return;

	/*
	 * *state was just applied. Read out the hardware state and do some
	 * checks.
	 */

	chip->ops->get_state(chip, pwm, &s1);
	trace_pwm_get(pwm, &s1);

	/*
	 * The lowlevel driver either ignored .polarity (which is a bug) or as
	 * best effort inverted .polarity and fixed .duty_cycle respectively.
	 * Undo this inversion and fixup for further tests.
	 */
	if (s1.enabled && s1.polarity != state->polarity) {
		s2.polarity = state->polarity;
		s2.duty_cycle = s1.period - s1.duty_cycle;
		s2.period = s1.period;
		s2.enabled = s1.enabled;
	} else {
		s2 = s1;
	}

	if (s2.polarity != state->polarity &&
	    state->duty_cycle < state->period)
		dev_warn(chip->dev, ".apply ignored .polarity\n");

	if (state->enabled &&
	    last->polarity == state->polarity &&
	    last->period > s2.period &&
	    last->period <= state->period)
		dev_warn(chip->dev,
			 ".apply didn't pick the best available period (requested: %llu, applied: %llu, possible: %llu)\n",
			 state->period, s2.period, last->period);

	if (state->enabled && state->period < s2.period)
		dev_warn(chip->dev,
			 ".apply is supposed to round down period (requested: %llu, applied: %llu)\n",
			 state->period, s2.period);

	if (state->enabled &&
	    last->polarity == state->polarity &&
	    last->period == s2.period &&
	    last->duty_cycle > s2.duty_cycle &&
	    last->duty_cycle <= state->duty_cycle)
		dev_warn(chip->dev,
			 ".apply didn't pick the best available duty cycle (requested: %llu/%llu, applied: %llu/%llu, possible: %llu/%llu)\n",
			 state->duty_cycle, state->period,
			 s2.duty_cycle, s2.period,
			 last->duty_cycle, last->period);

	if (state->enabled && state->duty_cycle < s2.duty_cycle)
		dev_warn(chip->dev,
			 ".apply is supposed to round down duty_cycle (requested: %llu/%llu, applied: %llu/%llu)\n",
			 state->duty_cycle, state->period,
			 s2.duty_cycle, s2.period);

	if (!state->enabled && s2.enabled && s2.duty_cycle > 0)
		dev_warn(chip->dev,
			 "requested disabled, but yielded enabled with duty > 0\n");

	/* reapply the state that the driver reported being configured. */
	err = chip->ops->apply(chip, pwm, &s1);
	if (err) {
		*last = s1;
		dev_err(chip->dev, "failed to reapply current setting\n");
		return;
	}

	trace_pwm_apply(pwm, &s1);

	chip->ops->get_state(chip, pwm, last);
	trace_pwm_get(pwm, last);

	/* reapplication of the current state should give an exact match */
	if (s1.enabled != last->enabled ||
	    s1.polarity != last->polarity ||
	    (s1.enabled && s1.period != last->period) ||
	    (s1.enabled && s1.duty_cycle != last->duty_cycle)) {
		dev_err(chip->dev,
			".apply is not idempotent (ena=%d pol=%d %llu/%llu) -> (ena=%d pol=%d %llu/%llu)\n",
			s1.enabled, s1.polarity, s1.duty_cycle, s1.period,
			last->enabled, last->polarity, last->duty_cycle,
			last->period);
	}
}