static int devfreq_passive_get_target_freq()

in governor_passive.c [15:100]

• 43 lines of code
• 13 McCabe index (conditional complexity)

static int devfreq_passive_get_target_freq(struct devfreq *devfreq,
					unsigned long *freq)
{
	struct devfreq_passive_data *p_data
			= (struct devfreq_passive_data *)devfreq->data;
	struct devfreq *parent_devfreq = (struct devfreq *)p_data->parent;
	unsigned long child_freq = ULONG_MAX;
	struct dev_pm_opp *opp, *p_opp;
	int i, count;

	/*
	 * If the devfreq device with passive governor has the specific method
	 * to determine the next frequency, should use the get_target_freq()
	 * of struct devfreq_passive_data.
	 */
	if (p_data->get_target_freq)
		return p_data->get_target_freq(devfreq, freq);

	/*
	 * If the parent and passive devfreq device uses the OPP table,
	 * get the next frequency by using the OPP table.
	 */

	/*
	 * - parent devfreq device uses the governors except for passive.
	 * - passive devfreq device uses the passive governor.
	 *
	 * Each devfreq has the OPP table. After deciding the new frequency
	 * from the governor of parent devfreq device, the passive governor
	 * need to get the index of new frequency on OPP table of parent
	 * device. And then the index is used for getting the suitable
	 * new frequency for passive devfreq device.
	 */
	if (!devfreq->profile || !devfreq->profile->freq_table
		|| devfreq->profile->max_state <= 0)
		return -EINVAL;

	/*
	 * The passive governor have to get the correct frequency from OPP
	 * list of parent device. Because in this case, *freq is temporary
	 * value which is decided by ondemand governor.
	 */
	if (devfreq->opp_table && parent_devfreq->opp_table) {
		p_opp = devfreq_recommended_opp(parent_devfreq->dev.parent,
						freq, 0);
		if (IS_ERR(p_opp))
			return PTR_ERR(p_opp);

		opp = dev_pm_opp_xlate_required_opp(parent_devfreq->opp_table,
						    devfreq->opp_table, p_opp);
		dev_pm_opp_put(p_opp);

		if (IS_ERR(opp))
			goto no_required_opp;

		*freq = dev_pm_opp_get_freq(opp);
		dev_pm_opp_put(opp);

		return 0;
	}

no_required_opp:
	/*
	 * Get the OPP table's index of decided frequency by governor
	 * of parent device.
	 */
	for (i = 0; i < parent_devfreq->profile->max_state; i++)
		if (parent_devfreq->profile->freq_table[i] == *freq)
			break;

	if (i == parent_devfreq->profile->max_state)
		return -EINVAL;

	/* Get the suitable frequency by using index of parent device. */
	if (i < devfreq->profile->max_state) {
		child_freq = devfreq->profile->freq_table[i];
	} else {
		count = devfreq->profile->max_state;
		child_freq = devfreq->profile->freq_table[count - 1];
	}

	/* Return the suitable frequency for passive device. */
	*freq = child_freq;

	return 0;
}