static int device_resume()

in power/main.c [896:979]

• 62 lines of code
• 16 McCabe index (conditional complexity)

static int device_resume(struct device *dev, pm_message_t state, bool async)
{
	pm_callback_t callback = NULL;
	const char *info = NULL;
	int error = 0;
	DECLARE_DPM_WATCHDOG_ON_STACK(wd);

	TRACE_DEVICE(dev);
	TRACE_RESUME(0);

	if (dev->power.syscore)
		goto Complete;

	if (dev->power.direct_complete) {
		/* Match the pm_runtime_disable() in __device_suspend(). */
		pm_runtime_enable(dev);
		goto Complete;
	}

	if (!dpm_wait_for_superior(dev, async))
		goto Complete;

	dpm_watchdog_set(&wd, dev);
	device_lock(dev);

	/*
	 * This is a fib.  But we'll allow new children to be added below
	 * a resumed device, even if the device hasn't been completed yet.
	 */
	dev->power.is_prepared = false;

	if (!dev->power.is_suspended)
		goto Unlock;

	if (dev->pm_domain) {
		info = "power domain ";
		callback = pm_op(&dev->pm_domain->ops, state);
		goto Driver;
	}

	if (dev->type && dev->type->pm) {
		info = "type ";
		callback = pm_op(dev->type->pm, state);
		goto Driver;
	}

	if (dev->class && dev->class->pm) {
		info = "class ";
		callback = pm_op(dev->class->pm, state);
		goto Driver;
	}

	if (dev->bus) {
		if (dev->bus->pm) {
			info = "bus ";
			callback = pm_op(dev->bus->pm, state);
		} else if (dev->bus->resume) {
			info = "legacy bus ";
			callback = dev->bus->resume;
			goto End;
		}
	}

 Driver:
	if (!callback && dev->driver && dev->driver->pm) {
		info = "driver ";
		callback = pm_op(dev->driver->pm, state);
	}

 End:
	error = dpm_run_callback(callback, dev, state, info);
	dev->power.is_suspended = false;

 Unlock:
	device_unlock(dev);
	dpm_watchdog_clear(&wd);

 Complete:
	complete_all(&dev->power.completion);

	TRACE_RESUME(error);

	return error;
}