int dev_pm_opp_of_register_em()

in of.c [1459:1507]

• 35 lines of code
• 7 McCabe index (conditional complexity)

int dev_pm_opp_of_register_em(struct device *dev, struct cpumask *cpus)
{
	struct em_data_callback em_cb = EM_DATA_CB(_get_power);
	struct device_node *np;
	int ret, nr_opp;
	u32 cap;

	if (IS_ERR_OR_NULL(dev)) {
		ret = -EINVAL;
		goto failed;
	}

	nr_opp = dev_pm_opp_get_opp_count(dev);
	if (nr_opp <= 0) {
		ret = -EINVAL;
		goto failed;
	}

	np = of_node_get(dev->of_node);
	if (!np) {
		ret = -EINVAL;
		goto failed;
	}

	/*
	 * Register an EM only if the 'dynamic-power-coefficient' property is
	 * set in devicetree. It is assumed the voltage values are known if that
	 * property is set since it is useless otherwise. If voltages are not
	 * known, just let the EM registration fail with an error to alert the
	 * user about the inconsistent configuration.
	 */
	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
	of_node_put(np);
	if (ret || !cap) {
		dev_dbg(dev, "Couldn't find proper 'dynamic-power-coefficient' in DT\n");
		ret = -EINVAL;
		goto failed;
	}

	ret = em_dev_register_perf_domain(dev, nr_opp, &em_cb, cpus, true);
	if (ret)
		goto failed;

	return 0;

failed:
	dev_dbg(dev, "Couldn't register Energy Model %d\n", ret);
	return ret;
}