Contributors: 40
Author Tokens Token Proportion Commits Commit Proportion
Viresh Kumar 4092 67.59% 93 60.39%
Georgi Djakov 458 7.57% 2 1.30%
Lukasz Luba 327 5.40% 8 5.19%
Quentin Perret 291 4.81% 1 0.65%
Sibi Sankar 127 2.10% 1 0.65%
Shawn Guo 117 1.93% 2 1.30%
Nishanth Menon 100 1.65% 6 3.90%
Ulf Hansson 99 1.64% 2 1.30%
Yangtao Li 59 0.97% 1 0.65%
Saravana Kannan 54 0.89% 1 0.65%
Dave Gerlach 44 0.73% 3 1.95%
James Calligeros 40 0.66% 1 0.65%
Dmitry Osipenko 34 0.56% 2 1.30%
Liang He 33 0.55% 2 1.30%
MyungJoo Ham 17 0.28% 1 0.65%
Sudeep Holla 15 0.25% 2 1.30%
Nathan Chancellor 15 0.25% 1 0.65%
Anson Huang 14 0.23% 1 0.65%
Nicola Mazzucato 12 0.20% 1 0.65%
Arnd Bergmann 11 0.18% 1 0.65%
Waldemar Rymarkiewicz 11 0.18% 1 0.65%
Andrew Halaney 10 0.17% 2 1.30%
Pi-Cheng Chen 10 0.17% 1 0.65%
Michał Mirosław 10 0.17% 1 0.65%
Liam Girdwood 10 0.17% 1 0.65%
Dmitry Torokhov 8 0.13% 1 0.65%
Stephan Gerhold 7 0.12% 1 0.65%
Langsdorf, Mark 4 0.07% 1 0.65%
Yue haibing 4 0.07% 1 0.65%
Paul Gortmaker 3 0.05% 1 0.65%
Rob Herring 3 0.05% 2 1.30%
Vincent Guittot 3 0.05% 1 0.65%
Dan Carpenter 2 0.03% 1 0.65%
Thomas Gleixner 2 0.03% 1 0.65%
Rajendra Nayak 2 0.03% 1 0.65%
Pavankumar Kondeti 2 0.03% 1 0.65%
Walter Lozano 1 0.02% 1 0.65%
Yang Yingliang 1 0.02% 1 0.65%
Masahiro Yamada 1 0.02% 1 0.65%
Bartlomiej Zolnierkiewicz 1 0.02% 1 0.65%
Total 6054 154 


// SPDX-License-Identifier: GPL-2.0-only
/*
 * Generic OPP OF helpers
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *	Nishanth Menon
 *	Romit Dasgupta
 *	Kevin Hilman
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/cpu.h>
#include <linux/errno.h>
#include <linux/device.h>
#include <linux/of.h>
#include <linux/pm_domain.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/energy_model.h>

#include "opp.h"

/* OPP tables with uninitialized required OPPs, protected by opp_table_lock */
static LIST_HEAD(lazy_opp_tables);

/*
 * Returns opp descriptor node for a device node, caller must
 * do of_node_put().
 */
static struct device_node *_opp_of_get_opp_desc_node(struct device_node *np,
						     int index)
{
	/* "operating-points-v2" can be an array for power domain providers */
	return of_parse_phandle(np, "operating-points-v2", index);
}

/* Returns opp descriptor node for a device, caller must do of_node_put() */
struct device_node *dev_pm_opp_of_get_opp_desc_node(struct device *dev)
{
	return _opp_of_get_opp_desc_node(dev->of_node, 0);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_opp_desc_node);

struct opp_table *_managed_opp(struct device *dev, int index)
{
	struct opp_table *opp_table, *managed_table = NULL;
	struct device_node *np;

	np = _opp_of_get_opp_desc_node(dev->of_node, index);
	if (!np)
		return NULL;

	list_for_each_entry(opp_table, &opp_tables, node) {
		if (opp_table->np == np) {
			/*
			 * Multiple devices can point to the same OPP table and
			 * so will have same node-pointer, np.
			 *
			 * But the OPPs will be considered as shared only if the
			 * OPP table contains a "opp-shared" property.
			 */
			if (opp_table->shared_opp == OPP_TABLE_ACCESS_SHARED) {
				_get_opp_table_kref(opp_table);
				managed_table = opp_table;
			}

			break;
		}
	}

	of_node_put(np);

	return managed_table;
}

/* The caller must call dev_pm_opp_put() after the OPP is used */
static struct dev_pm_opp *_find_opp_of_np(struct opp_table *opp_table,
					  struct device_node *opp_np)
{
	struct dev_pm_opp *opp;

	mutex_lock(&opp_table->lock);

	list_for_each_entry(opp, &opp_table->opp_list, node) {
		if (opp->np == opp_np) {
			dev_pm_opp_get(opp);
			mutex_unlock(&opp_table->lock);
			return opp;
		}
	}

	mutex_unlock(&opp_table->lock);

	return NULL;
}

static struct device_node *of_parse_required_opp(struct device_node *np,
						 int index)
{
	return of_parse_phandle(np, "required-opps", index);
}

/* The caller must call dev_pm_opp_put_opp_table() after the table is used */
static struct opp_table *_find_table_of_opp_np(struct device_node *opp_np)
{
	struct opp_table *opp_table;
	struct device_node *opp_table_np;

	opp_table_np = of_get_parent(opp_np);
	if (!opp_table_np)
		goto err;

	/* It is safe to put the node now as all we need now is its address */
	of_node_put(opp_table_np);

	mutex_lock(&opp_table_lock);
	list_for_each_entry(opp_table, &opp_tables, node) {
		if (opp_table_np == opp_table->np) {
			_get_opp_table_kref(opp_table);
			mutex_unlock(&opp_table_lock);
			return opp_table;
		}
	}
	mutex_unlock(&opp_table_lock);

err:
	return ERR_PTR(-ENODEV);
}

/* Free resources previously acquired by _opp_table_alloc_required_tables() */
static void _opp_table_free_required_tables(struct opp_table *opp_table)
{
	struct opp_table **required_opp_tables = opp_table->required_opp_tables;
	int i;

	if (!required_opp_tables)
		return;

	for (i = 0; i < opp_table->required_opp_count; i++) {
		if (IS_ERR_OR_NULL(required_opp_tables[i]))
			continue;

		dev_pm_opp_put_opp_table(required_opp_tables[i]);
	}

	kfree(required_opp_tables);

	opp_table->required_opp_count = 0;
	opp_table->required_opp_tables = NULL;

	mutex_lock(&opp_table_lock);
	list_del(&opp_table->lazy);
	mutex_unlock(&opp_table_lock);
}

/*
 * Populate all devices and opp tables which are part of "required-opps" list.
 * Checking only the first OPP node should be enough.
 */
static void _opp_table_alloc_required_tables(struct opp_table *opp_table,
					     struct device *dev,
					     struct device_node *opp_np)
{
	struct opp_table **required_opp_tables;
	struct device_node *required_np, *np;
	bool lazy = false;
	int count, i, size;

	/* Traversing the first OPP node is all we need */
	np = of_get_next_available_child(opp_np, NULL);
	if (!np) {
		dev_warn(dev, "Empty OPP table\n");

		return;
	}

	count = of_count_phandle_with_args(np, "required-opps", NULL);
	if (count <= 0)
		goto put_np;

	size = sizeof(*required_opp_tables) + sizeof(*opp_table->required_devs);
	required_opp_tables = kcalloc(count, size, GFP_KERNEL);
	if (!required_opp_tables)
		goto put_np;

	opp_table->required_opp_tables = required_opp_tables;
	opp_table->required_devs = (void *)(required_opp_tables + count);
	opp_table->required_opp_count = count;

	for (i = 0; i < count; i++) {
		required_np = of_parse_required_opp(np, i);
		if (!required_np)
			goto free_required_tables;

		required_opp_tables[i] = _find_table_of_opp_np(required_np);
		of_node_put(required_np);

		if (IS_ERR(required_opp_tables[i]))
			lazy = true;
	}

	/* Let's do the linking later on */
	if (lazy) {
		/*
		 * The OPP table is not held while allocating the table, take it
		 * now to avoid corruption to the lazy_opp_tables list.
		 */
		mutex_lock(&opp_table_lock);
		list_add(&opp_table->lazy, &lazy_opp_tables);
		mutex_unlock(&opp_table_lock);
	}

	goto put_np;

free_required_tables:
	_opp_table_free_required_tables(opp_table);
put_np:
	of_node_put(np);
}

void _of_init_opp_table(struct opp_table *opp_table, struct device *dev,
			int index)
{
	struct device_node *np, *opp_np;
	u32 val;

	/*
	 * Only required for backward compatibility with v1 bindings, but isn't
	 * harmful for other cases. And so we do it unconditionally.
	 */
	np = of_node_get(dev->of_node);
	if (!np)
		return;

	if (!of_property_read_u32(np, "clock-latency", &val))
		opp_table->clock_latency_ns_max = val;
	of_property_read_u32(np, "voltage-tolerance",
			     &opp_table->voltage_tolerance_v1);

	if (of_property_present(np, "#power-domain-cells"))
		opp_table->is_genpd = true;

	/* Get OPP table node */
	opp_np = _opp_of_get_opp_desc_node(np, index);
	of_node_put(np);

	if (!opp_np)
		return;

	if (of_property_read_bool(opp_np, "opp-shared"))
		opp_table->shared_opp = OPP_TABLE_ACCESS_SHARED;
	else
		opp_table->shared_opp = OPP_TABLE_ACCESS_EXCLUSIVE;

	opp_table->np = opp_np;

	_opp_table_alloc_required_tables(opp_table, dev, opp_np);
}

void _of_clear_opp_table(struct opp_table *opp_table)
{
	_opp_table_free_required_tables(opp_table);
	of_node_put(opp_table->np);
}

/*
 * Release all resources previously acquired with a call to
 * _of_opp_alloc_required_opps().
 */
static void _of_opp_free_required_opps(struct opp_table *opp_table,
				       struct dev_pm_opp *opp)
{
	struct dev_pm_opp **required_opps = opp->required_opps;
	int i;

	if (!required_opps)
		return;

	for (i = 0; i < opp_table->required_opp_count; i++) {
		if (!required_opps[i])
			continue;

		/* Put the reference back */
		dev_pm_opp_put(required_opps[i]);
	}

	opp->required_opps = NULL;
	kfree(required_opps);
}

void _of_clear_opp(struct opp_table *opp_table, struct dev_pm_opp *opp)
{
	_of_opp_free_required_opps(opp_table, opp);
	of_node_put(opp->np);
}

static int _link_required_opps(struct dev_pm_opp *opp, struct opp_table *opp_table,
			       struct opp_table *required_table, int index)
{
	struct device_node *np;

	np = of_parse_required_opp(opp->np, index);
	if (unlikely(!np))
		return -ENODEV;

	opp->required_opps[index] = _find_opp_of_np(required_table, np);
	of_node_put(np);

	if (!opp->required_opps[index]) {
		pr_err("%s: Unable to find required OPP node: %pOF (%d)\n",
		       __func__, opp->np, index);
		return -ENODEV;
	}

	/*
	 * There are two genpd (as required-opp) cases that we need to handle,
	 * devices with a single genpd and ones with multiple genpds.
	 *
	 * The single genpd case requires special handling as we need to use the
	 * same `dev` structure (instead of a virtual one provided by genpd
	 * core) for setting the performance state.
	 *
	 * It doesn't make sense for a device's DT entry to have both
	 * "opp-level" and single "required-opps" entry pointing to a genpd's
	 * OPP, as that would make the OPP core call
	 * dev_pm_domain_set_performance_state() for two different values for
	 * the same device structure. Lets treat single genpd configuration as a
	 * case where the OPP's level is directly available without required-opp
	 * link in the DT.
	 *
	 * Just update the `level` with the right value, which
	 * dev_pm_opp_set_opp() will take care of in the normal path itself.
	 *
	 * There is another case though, where a genpd's OPP table has
	 * required-opps set to a parent genpd. The OPP core expects the user to
	 * set the respective required `struct device` pointer via
	 * dev_pm_opp_set_config().
	 */
	if (required_table->is_genpd && opp_table->required_opp_count == 1 &&
	    !opp_table->required_devs[0]) {
		/* Genpd core takes care of propagation to parent genpd */
		if (!opp_table->is_genpd) {
			if (!WARN_ON(opp->level != OPP_LEVEL_UNSET))
				opp->level = opp->required_opps[0]->level;
		}
	}

	return 0;
}

/* Populate all required OPPs which are part of "required-opps" list */
static int _of_opp_alloc_required_opps(struct opp_table *opp_table,
				       struct dev_pm_opp *opp)
{
	struct opp_table *required_table;
	int i, ret, count = opp_table->required_opp_count;

	if (!count)
		return 0;

	opp->required_opps = kcalloc(count, sizeof(*opp->required_opps), GFP_KERNEL);
	if (!opp->required_opps)
		return -ENOMEM;

	for (i = 0; i < count; i++) {
		required_table = opp_table->required_opp_tables[i];

		/* Required table not added yet, we will link later */
		if (IS_ERR_OR_NULL(required_table))
			continue;

		ret = _link_required_opps(opp, opp_table, required_table, i);
		if (ret)
			goto free_required_opps;
	}

	return 0;

free_required_opps:
	_of_opp_free_required_opps(opp_table, opp);

	return ret;
}

/* Link required OPPs for an individual OPP */
static int lazy_link_required_opps(struct opp_table *opp_table,
				   struct opp_table *new_table, int index)
{
	struct dev_pm_opp *opp;
	int ret;

	list_for_each_entry(opp, &opp_table->opp_list, node) {
		ret = _link_required_opps(opp, opp_table, new_table, index);
		if (ret)
			return ret;
	}

	return 0;
}

/* Link required OPPs for all OPPs of the newly added OPP table */
static void lazy_link_required_opp_table(struct opp_table *new_table)
{
	struct opp_table *opp_table, *temp, **required_opp_tables;
	struct device_node *required_np, *opp_np, *required_table_np;
	struct dev_pm_opp *opp;
	int i, ret;

	mutex_lock(&opp_table_lock);

	list_for_each_entry_safe(opp_table, temp, &lazy_opp_tables, lazy) {
		bool lazy = false;

		/* opp_np can't be invalid here */
		opp_np = of_get_next_available_child(opp_table->np, NULL);

		for (i = 0; i < opp_table->required_opp_count; i++) {
			required_opp_tables = opp_table->required_opp_tables;

			/* Required opp-table is already parsed */
			if (!IS_ERR(required_opp_tables[i]))
				continue;

			/* required_np can't be invalid here */
			required_np = of_parse_required_opp(opp_np, i);
			required_table_np = of_get_parent(required_np);

			of_node_put(required_table_np);
			of_node_put(required_np);

			/*
			 * Newly added table isn't the required opp-table for
			 * opp_table.
			 */
			if (required_table_np != new_table->np) {
				lazy = true;
				continue;
			}

			required_opp_tables[i] = new_table;
			_get_opp_table_kref(new_table);

			/* Link OPPs now */
			ret = lazy_link_required_opps(opp_table, new_table, i);
			if (ret) {
				/* The OPPs will be marked unusable */
				lazy = false;
				break;
			}
		}

		of_node_put(opp_np);

		/* All required opp-tables found, remove from lazy list */
		if (!lazy) {
			list_del_init(&opp_table->lazy);

			list_for_each_entry(opp, &opp_table->opp_list, node)
				_required_opps_available(opp, opp_table->required_opp_count);
		}
	}

	mutex_unlock(&opp_table_lock);
}

static int _bandwidth_supported(struct device *dev, struct opp_table *opp_table)
{
	struct device_node *np, *opp_np;
	struct property *prop;

	if (!opp_table) {
		np = of_node_get(dev->of_node);
		if (!np)
			return -ENODEV;

		opp_np = _opp_of_get_opp_desc_node(np, 0);
		of_node_put(np);
	} else {
		opp_np = of_node_get(opp_table->np);
	}

	/* Lets not fail in case we are parsing opp-v1 bindings */
	if (!opp_np)
		return 0;

	/* Checking only first OPP is sufficient */
	np = of_get_next_available_child(opp_np, NULL);
	of_node_put(opp_np);
	if (!np) {
		dev_err(dev, "OPP table empty\n");
		return -EINVAL;
	}

	prop = of_find_property(np, "opp-peak-kBps", NULL);
	of_node_put(np);

	if (!prop || !prop->length)
		return 0;

	return 1;
}

int dev_pm_opp_of_find_icc_paths(struct device *dev,
				 struct opp_table *opp_table)
{
	struct device_node *np;
	int ret, i, count, num_paths;
	struct icc_path **paths;

	ret = _bandwidth_supported(dev, opp_table);
	if (ret == -EINVAL)
		return 0; /* Empty OPP table is a valid corner-case, let's not fail */
	else if (ret <= 0)
		return ret;

	ret = 0;

	np = of_node_get(dev->of_node);
	if (!np)
		return 0;

	count = of_count_phandle_with_args(np, "interconnects",
					   "#interconnect-cells");
	of_node_put(np);
	if (count < 0)
		return 0;

	/* two phandles when #interconnect-cells = <1> */
	if (count % 2) {
		dev_err(dev, "%s: Invalid interconnects values\n", __func__);
		return -EINVAL;
	}

	num_paths = count / 2;
	paths = kcalloc(num_paths, sizeof(*paths), GFP_KERNEL);
	if (!paths)
		return -ENOMEM;

	for (i = 0; i < num_paths; i++) {
		paths[i] = of_icc_get_by_index(dev, i);
		if (IS_ERR(paths[i])) {
			ret = dev_err_probe(dev, PTR_ERR(paths[i]), "%s: Unable to get path%d\n", __func__, i);
			goto err;
		}
	}

	if (opp_table) {
		opp_table->paths = paths;
		opp_table->path_count = num_paths;
		return 0;
	}

err:
	while (i--)
		icc_put(paths[i]);

	kfree(paths);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_find_icc_paths);

static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
			      struct device_node *np)
{
	unsigned int levels = opp_table->supported_hw_count;
	int count, versions, ret, i, j;
	u32 val;

	if (!opp_table->supported_hw) {
		/*
		 * In the case that no supported_hw has been set by the
		 * platform but there is an opp-supported-hw value set for
		 * an OPP then the OPP should not be enabled as there is
		 * no way to see if the hardware supports it.
		 */
		if (of_property_present(np, "opp-supported-hw"))
			return false;
		else
			return true;
	}

	count = of_property_count_u32_elems(np, "opp-supported-hw");
	if (count <= 0 || count % levels) {
		dev_err(dev, "%s: Invalid opp-supported-hw property (%d)\n",
			__func__, count);
		return false;
	}

	versions = count / levels;

	/* All levels in at least one of the versions should match */
	for (i = 0; i < versions; i++) {
		bool supported = true;

		for (j = 0; j < levels; j++) {
			ret = of_property_read_u32_index(np, "opp-supported-hw",
							 i * levels + j, &val);
			if (ret) {
				dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
					 __func__, i * levels + j, ret);
				return false;
			}

			/* Check if the level is supported */
			if (!(val & opp_table->supported_hw[j])) {
				supported = false;
				break;
			}
		}

		if (supported)
			return true;
	}

	return false;
}

static u32 *_parse_named_prop(struct dev_pm_opp *opp, struct device *dev,
			      struct opp_table *opp_table,
			      const char *prop_type, bool *triplet)
{
	struct property *prop = NULL;
	char name[NAME_MAX];
	int count, ret;
	u32 *out;

	/* Search for "opp-<prop_type>-<name>" */
	if (opp_table->prop_name) {
		snprintf(name, sizeof(name), "opp-%s-%s", prop_type,
			 opp_table->prop_name);
		prop = of_find_property(opp->np, name, NULL);
	}

	if (!prop) {
		/* Search for "opp-<prop_type>" */
		snprintf(name, sizeof(name), "opp-%s", prop_type);
		prop = of_find_property(opp->np, name, NULL);
		if (!prop)
			return NULL;
	}

	count = of_property_count_u32_elems(opp->np, name);
	if (count < 0) {
		dev_err(dev, "%s: Invalid %s property (%d)\n", __func__, name,
			count);
		return ERR_PTR(count);
	}

	/*
	 * Initialize regulator_count, if regulator information isn't provided
	 * by the platform. Now that one of the properties is available, fix the
	 * regulator_count to 1.
	 */
	if (unlikely(opp_table->regulator_count == -1))
		opp_table->regulator_count = 1;

	if (count != opp_table->regulator_count &&
	    (!triplet || count != opp_table->regulator_count * 3)) {
		dev_err(dev, "%s: Invalid number of elements in %s property (%u) with supplies (%d)\n",
			__func__, prop_type, count, opp_table->regulator_count);
		return ERR_PTR(-EINVAL);
	}

	out = kmalloc_array(count, sizeof(*out), GFP_KERNEL);
	if (!out)
		return ERR_PTR(-EINVAL);

	ret = of_property_read_u32_array(opp->np, name, out, count);
	if (ret) {
		dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
		kfree(out);
		return ERR_PTR(-EINVAL);
	}

	if (triplet)
		*triplet = count != opp_table->regulator_count;

	return out;
}

static u32 *opp_parse_microvolt(struct dev_pm_opp *opp, struct device *dev,
				struct opp_table *opp_table, bool *triplet)
{
	u32 *microvolt;

	microvolt = _parse_named_prop(opp, dev, opp_table, "microvolt", triplet);
	if (IS_ERR(microvolt))
		return microvolt;

	if (!microvolt) {
		/*
		 * Missing property isn't a problem, but an invalid
		 * entry is. This property isn't optional if regulator
		 * information is provided. Check only for the first OPP, as
		 * regulator_count may get initialized after that to a valid
		 * value.
		 */
		if (list_empty(&opp_table->opp_list) &&
		    opp_table->regulator_count > 0) {
			dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
				__func__);
			return ERR_PTR(-EINVAL);
		}
	}

	return microvolt;
}

static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
			      struct opp_table *opp_table)
{
	u32 *microvolt, *microamp, *microwatt;
	int ret = 0, i, j;
	bool triplet;

	microvolt = opp_parse_microvolt(opp, dev, opp_table, &triplet);
	if (IS_ERR(microvolt))
		return PTR_ERR(microvolt);

	microamp = _parse_named_prop(opp, dev, opp_table, "microamp", NULL);
	if (IS_ERR(microamp)) {
		ret = PTR_ERR(microamp);
		goto free_microvolt;
	}

	microwatt = _parse_named_prop(opp, dev, opp_table, "microwatt", NULL);
	if (IS_ERR(microwatt)) {
		ret = PTR_ERR(microwatt);
		goto free_microamp;
	}

	/*
	 * Initialize regulator_count if it is uninitialized and no properties
	 * are found.
	 */
	if (unlikely(opp_table->regulator_count == -1)) {
		opp_table->regulator_count = 0;
		return 0;
	}

	for (i = 0, j = 0; i < opp_table->regulator_count; i++) {
		if (microvolt) {
			opp->supplies[i].u_volt = microvolt[j++];

			if (triplet) {
				opp->supplies[i].u_volt_min = microvolt[j++];
				opp->supplies[i].u_volt_max = microvolt[j++];
			} else {
				opp->supplies[i].u_volt_min = opp->supplies[i].u_volt;
				opp->supplies[i].u_volt_max = opp->supplies[i].u_volt;
			}
		}

		if (microamp)
			opp->supplies[i].u_amp = microamp[i];

		if (microwatt)
			opp->supplies[i].u_watt = microwatt[i];
	}

	kfree(microwatt);
free_microamp:
	kfree(microamp);
free_microvolt:
	kfree(microvolt);

	return ret;
}

/**
 * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
 *				  entries
 * @dev:	device pointer used to lookup OPP table.
 *
 * Free OPPs created using static entries present in DT.
 */
void dev_pm_opp_of_remove_table(struct device *dev)
{
	dev_pm_opp_remove_table(dev);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);

static int _read_rate(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
		      struct device_node *np)
{
	struct property *prop;
	int i, count, ret;
	u64 *rates;

	prop = of_find_property(np, "opp-hz", NULL);
	if (!prop)
		return -ENODEV;

	count = prop->length / sizeof(u64);
	if (opp_table->clk_count != count) {
		pr_err("%s: Count mismatch between opp-hz and clk_count (%d %d)\n",
		       __func__, count, opp_table->clk_count);
		return -EINVAL;
	}

	rates = kmalloc_array(count, sizeof(*rates), GFP_KERNEL);
	if (!rates)
		return -ENOMEM;

	ret = of_property_read_u64_array(np, "opp-hz", rates, count);
	if (ret) {
		pr_err("%s: Error parsing opp-hz: %d\n", __func__, ret);
	} else {
		/*
		 * Rate is defined as an unsigned long in clk API, and so
		 * casting explicitly to its type. Must be fixed once rate is 64
		 * bit guaranteed in clk API.
		 */
		for (i = 0; i < count; i++) {
			new_opp->rates[i] = (unsigned long)rates[i];

			/* This will happen for frequencies > 4.29 GHz */
			WARN_ON(new_opp->rates[i] != rates[i]);
		}
	}

	kfree(rates);

	return ret;
}

static int _read_bw(struct dev_pm_opp *new_opp, struct opp_table *opp_table,
		    struct device_node *np, bool peak)
{
	const char *name = peak ? "opp-peak-kBps" : "opp-avg-kBps";
	struct property *prop;
	int i, count, ret;
	u32 *bw;

	prop = of_find_property(np, name, NULL);
	if (!prop)
		return -ENODEV;

	count = prop->length / sizeof(u32);
	if (opp_table->path_count != count) {
		pr_err("%s: Mismatch between %s and paths (%d %d)\n",
				__func__, name, count, opp_table->path_count);
		return -EINVAL;
	}

	bw = kmalloc_array(count, sizeof(*bw), GFP_KERNEL);
	if (!bw)
		return -ENOMEM;

	ret = of_property_read_u32_array(np, name, bw, count);
	if (ret) {
		pr_err("%s: Error parsing %s: %d\n", __func__, name, ret);
		goto out;
	}

	for (i = 0; i < count; i++) {
		if (peak)
			new_opp->bandwidth[i].peak = kBps_to_icc(bw[i]);
		else
			new_opp->bandwidth[i].avg = kBps_to_icc(bw[i]);
	}

out:
	kfree(bw);
	return ret;
}

static int _read_opp_key(struct dev_pm_opp *new_opp,
			 struct opp_table *opp_table, struct device_node *np)
{
	bool found = false;
	int ret;

	ret = _read_rate(new_opp, opp_table, np);
	if (!ret)
		found = true;
	else if (ret != -ENODEV)
		return ret;

	/*
	 * Bandwidth consists of peak and average (optional) values:
	 * opp-peak-kBps = <path1_value path2_value>;
	 * opp-avg-kBps = <path1_value path2_value>;
	 */
	ret = _read_bw(new_opp, opp_table, np, true);
	if (!ret) {
		found = true;
		ret = _read_bw(new_opp, opp_table, np, false);
	}

	/* The properties were found but we failed to parse them */
	if (ret && ret != -ENODEV)
		return ret;

	if (!of_property_read_u32(np, "opp-level", &new_opp->level))
		found = true;

	if (found)
		return 0;

	return ret;
}

/**
 * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
 * @opp_table:	OPP table
 * @dev:	device for which we do this operation
 * @np:		device node
 *
 * This function adds an opp definition to the opp table and returns status. The
 * opp can be controlled using dev_pm_opp_enable/disable functions and may be
 * removed by dev_pm_opp_remove.
 *
 * Return:
 * Valid OPP pointer:
 *		On success
 * NULL:
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 *		OR if the OPP is not supported by hardware.
 * ERR_PTR(-EEXIST):
 *		Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * ERR_PTR(-ENOMEM):
 *		Memory allocation failure
 * ERR_PTR(-EINVAL):
 *		Failed parsing the OPP node
 */
static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
		struct device *dev, struct device_node *np)
{
	struct dev_pm_opp *new_opp;
	u32 val;
	int ret;

	new_opp = _opp_allocate(opp_table);
	if (!new_opp)
		return ERR_PTR(-ENOMEM);

	ret = _read_opp_key(new_opp, opp_table, np);
	if (ret < 0) {
		dev_err(dev, "%s: opp key field not found\n", __func__);
		goto free_opp;
	}

	/* Check if the OPP supports hardware's hierarchy of versions or not */
	if (!_opp_is_supported(dev, opp_table, np)) {
		dev_dbg(dev, "OPP not supported by hardware: %s\n",
			of_node_full_name(np));
		goto free_opp;
	}

	new_opp->turbo = of_property_read_bool(np, "turbo-mode");

	new_opp->np = of_node_get(np);
	new_opp->dynamic = false;
	new_opp->available = true;

	ret = _of_opp_alloc_required_opps(opp_table, new_opp);
	if (ret)
		goto free_opp;

	if (!of_property_read_u32(np, "clock-latency-ns", &val))
		new_opp->clock_latency_ns = val;

	ret = opp_parse_supplies(new_opp, dev, opp_table);
	if (ret)
		goto free_required_opps;

	ret = _opp_add(dev, new_opp, opp_table);
	if (ret) {
		/* Don't return error for duplicate OPPs */
		if (ret == -EBUSY)
			ret = 0;
		goto free_required_opps;
	}

	/* OPP to select on device suspend */
	if (of_property_read_bool(np, "opp-suspend")) {
		if (opp_table->suspend_opp) {
			/* Pick the OPP with higher rate/bw/level as suspend OPP */
			if (_opp_compare_key(opp_table, new_opp, opp_table->suspend_opp) == 1) {
				opp_table->suspend_opp->suspend = false;
				new_opp->suspend = true;
				opp_table->suspend_opp = new_opp;
			}
		} else {
			new_opp->suspend = true;
			opp_table->suspend_opp = new_opp;
		}
	}

	if (new_opp->clock_latency_ns > opp_table->clock_latency_ns_max)
		opp_table->clock_latency_ns_max = new_opp->clock_latency_ns;

	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu latency:%lu level:%u\n",
		 __func__, new_opp->turbo, new_opp->rates[0],
		 new_opp->supplies[0].u_volt, new_opp->supplies[0].u_volt_min,
		 new_opp->supplies[0].u_volt_max, new_opp->clock_latency_ns,
		 new_opp->level);

	/*
	 * Notify the changes in the availability of the operable
	 * frequency/voltage list.
	 */
	blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADD, new_opp);
	return new_opp;

free_required_opps:
	_of_opp_free_required_opps(opp_table, new_opp);
free_opp:
	_opp_free(new_opp);

	return ret ? ERR_PTR(ret) : NULL;
}

/* Initializes OPP tables based on new bindings */
static int _of_add_opp_table_v2(struct device *dev, struct opp_table *opp_table)
{
	struct device_node *np;
	int ret, count = 0;
	struct dev_pm_opp *opp;

	/* OPP table is already initialized for the device */
	mutex_lock(&opp_table->lock);
	if (opp_table->parsed_static_opps) {
		opp_table->parsed_static_opps++;
		mutex_unlock(&opp_table->lock);
		return 0;
	}

	opp_table->parsed_static_opps = 1;
	mutex_unlock(&opp_table->lock);

	/* We have opp-table node now, iterate over it and add OPPs */
	for_each_available_child_of_node(opp_table->np, np) {
		opp = _opp_add_static_v2(opp_table, dev, np);
		if (IS_ERR(opp)) {
			ret = PTR_ERR(opp);
			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
				ret);
			of_node_put(np);
			goto remove_static_opp;
		} else if (opp) {
			count++;
		}
	}

	/* There should be one or more OPPs defined */
	if (!count) {
		dev_err(dev, "%s: no supported OPPs", __func__);
		ret = -ENOENT;
		goto remove_static_opp;
	}

	lazy_link_required_opp_table(opp_table);

	return 0;

remove_static_opp:
	_opp_remove_all_static(opp_table);

	return ret;
}

/* Initializes OPP tables based on old-deprecated bindings */
static int _of_add_opp_table_v1(struct device *dev, struct opp_table *opp_table)
{
	const struct property *prop;
	const __be32 *val;
	int nr, ret = 0;

	mutex_lock(&opp_table->lock);
	if (opp_table->parsed_static_opps) {
		opp_table->parsed_static_opps++;
		mutex_unlock(&opp_table->lock);
		return 0;
	}

	opp_table->parsed_static_opps = 1;
	mutex_unlock(&opp_table->lock);

	prop = of_find_property(dev->of_node, "operating-points", NULL);
	if (!prop) {
		ret = -ENODEV;
		goto remove_static_opp;
	}
	if (!prop->value) {
		ret = -ENODATA;
		goto remove_static_opp;
	}

	/*
	 * Each OPP is a set of tuples consisting of frequency and
	 * voltage like <freq-kHz vol-uV>.
	 */
	nr = prop->length / sizeof(u32);
	if (nr % 2) {
		dev_err(dev, "%s: Invalid OPP table\n", __func__);
		ret = -EINVAL;
		goto remove_static_opp;
	}

	val = prop->value;
	while (nr) {
		unsigned long freq = be32_to_cpup(val++) * 1000;
		unsigned long volt = be32_to_cpup(val++);
		struct dev_pm_opp_data data = {
			.freq = freq,
			.u_volt = volt,
		};

		ret = _opp_add_v1(opp_table, dev, &data, false);
		if (ret) {
			dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
				__func__, data.freq, ret);
			goto remove_static_opp;
		}
		nr -= 2;
	}

	return 0;

remove_static_opp:
	_opp_remove_all_static(opp_table);

	return ret;
}

static int _of_add_table_indexed(struct device *dev, int index)
{
	struct opp_table *opp_table;
	int ret, count;

	if (index) {
		/*
		 * If only one phandle is present, then the same OPP table
		 * applies for all index requests.
		 */
		count = of_count_phandle_with_args(dev->of_node,
						   "operating-points-v2", NULL);
		if (count == 1)
			index = 0;
	}

	opp_table = _add_opp_table_indexed(dev, index, true);
	if (IS_ERR(opp_table))
		return PTR_ERR(opp_table);

	/*
	 * OPPs have two version of bindings now. Also try the old (v1)
	 * bindings for backward compatibility with older dtbs.
	 */
	if (opp_table->np)
		ret = _of_add_opp_table_v2(dev, opp_table);
	else
		ret = _of_add_opp_table_v1(dev, opp_table);

	if (ret)
		dev_pm_opp_put_opp_table(opp_table);

	return ret;
}

static void devm_pm_opp_of_table_release(void *data)
{
	dev_pm_opp_of_remove_table(data);
}

static int _devm_of_add_table_indexed(struct device *dev, int index)
{
	int ret;

	ret = _of_add_table_indexed(dev, index);
	if (ret)
		return ret;

	return devm_add_action_or_reset(dev, devm_pm_opp_of_table_release, dev);
}

/**
 * devm_pm_opp_of_add_table() - Initialize opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 *
 * Register the initial OPP table with the OPP library for given device.
 *
 * The opp_table structure will be freed after the device is destroyed.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -ENODEV	when 'operating-points' property is not found or is invalid data
 *		in device node.
 * -ENODATA	when empty 'operating-points' property is found
 * -EINVAL	when invalid entries are found in opp-v2 table
 */
int devm_pm_opp_of_add_table(struct device *dev)
{
	return _devm_of_add_table_indexed(dev, 0);
}
EXPORT_SYMBOL_GPL(devm_pm_opp_of_add_table);

/**
 * dev_pm_opp_of_add_table() - Initialize opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 *
 * Register the initial OPP table with the OPP library for given device.
 *
 * Return:
 * 0		On success OR
 *		Duplicate OPPs (both freq and volt are same) and opp->available
 * -EEXIST	Freq are same and volt are different OR
 *		Duplicate OPPs (both freq and volt are same) and !opp->available
 * -ENOMEM	Memory allocation failure
 * -ENODEV	when 'operating-points' property is not found or is invalid data
 *		in device node.
 * -ENODATA	when empty 'operating-points' property is found
 * -EINVAL	when invalid entries are found in opp-v2 table
 */
int dev_pm_opp_of_add_table(struct device *dev)
{
	return _of_add_table_indexed(dev, 0);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table);

/**
 * dev_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 * @index:	Index number.
 *
 * Register the initial OPP table with the OPP library for given device only
 * using the "operating-points-v2" property.
 *
 * Return: Refer to dev_pm_opp_of_add_table() for return values.
 */
int dev_pm_opp_of_add_table_indexed(struct device *dev, int index)
{
	return _of_add_table_indexed(dev, index);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_add_table_indexed);

/**
 * devm_pm_opp_of_add_table_indexed() - Initialize indexed opp table from device tree
 * @dev:	device pointer used to lookup OPP table.
 * @index:	Index number.
 *
 * This is a resource-managed variant of dev_pm_opp_of_add_table_indexed().
 */
int devm_pm_opp_of_add_table_indexed(struct device *dev, int index)
{
	return _devm_of_add_table_indexed(dev, index);
}
EXPORT_SYMBOL_GPL(devm_pm_opp_of_add_table_indexed);

/* CPU device specific helpers */

/**
 * dev_pm_opp_of_cpumask_remove_table() - Removes OPP table for @cpumask
 * @cpumask:	cpumask for which OPP table needs to be removed
 *
 * This removes the OPP tables for CPUs present in the @cpumask.
 * This should be used only to remove static entries created from DT.
 */
void dev_pm_opp_of_cpumask_remove_table(const struct cpumask *cpumask)
{
	_dev_pm_opp_cpumask_remove_table(cpumask, -1);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_remove_table);

/**
 * dev_pm_opp_of_cpumask_add_table() - Adds OPP table for @cpumask
 * @cpumask:	cpumask for which OPP table needs to be added.
 *
 * This adds the OPP tables for CPUs present in the @cpumask.
 */
int dev_pm_opp_of_cpumask_add_table(const struct cpumask *cpumask)
{
	struct device *cpu_dev;
	int cpu, ret;

	if (WARN_ON(cpumask_empty(cpumask)))
		return -ENODEV;

	for_each_cpu(cpu, cpumask) {
		cpu_dev = get_cpu_device(cpu);
		if (!cpu_dev) {
			pr_err("%s: failed to get cpu%d device\n", __func__,
			       cpu);
			ret = -ENODEV;
			goto remove_table;
		}

		ret = dev_pm_opp_of_add_table(cpu_dev);
		if (ret) {
			/*
			 * OPP may get registered dynamically, don't print error
			 * message here.
			 */
			pr_debug("%s: couldn't find opp table for cpu:%d, %d\n",
				 __func__, cpu, ret);

			goto remove_table;
		}
	}

	return 0;

remove_table:
	/* Free all other OPPs */
	_dev_pm_opp_cpumask_remove_table(cpumask, cpu);

	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_cpumask_add_table);

/*
 * Works only for OPP v2 bindings.
 *
 * Returns -ENOENT if operating-points-v2 bindings aren't supported.
 */
/**
 * dev_pm_opp_of_get_sharing_cpus() - Get cpumask of CPUs sharing OPPs with
 *				      @cpu_dev using operating-points-v2
 *				      bindings.
 *
 * @cpu_dev:	CPU device for which we do this operation
 * @cpumask:	cpumask to update with information of sharing CPUs
 *
 * This updates the @cpumask with CPUs that are sharing OPPs with @cpu_dev.
 *
 * Returns -ENOENT if operating-points-v2 isn't present for @cpu_dev.
 */
int dev_pm_opp_of_get_sharing_cpus(struct device *cpu_dev,
				   struct cpumask *cpumask)
{
	struct device_node *np, *tmp_np, *cpu_np;
	int cpu, ret = 0;

	/* Get OPP descriptor node */
	np = dev_pm_opp_of_get_opp_desc_node(cpu_dev);
	if (!np) {
		dev_dbg(cpu_dev, "%s: Couldn't find opp node.\n", __func__);
		return -ENOENT;
	}

	cpumask_set_cpu(cpu_dev->id, cpumask);

	/* OPPs are shared ? */
	if (!of_property_read_bool(np, "opp-shared"))
		goto put_cpu_node;

	for_each_possible_cpu(cpu) {
		if (cpu == cpu_dev->id)
			continue;

		cpu_np = of_cpu_device_node_get(cpu);
		if (!cpu_np) {
			dev_err(cpu_dev, "%s: failed to get cpu%d node\n",
				__func__, cpu);
			ret = -ENOENT;
			goto put_cpu_node;
		}

		/* Get OPP descriptor node */
		tmp_np = _opp_of_get_opp_desc_node(cpu_np, 0);
		of_node_put(cpu_np);
		if (!tmp_np) {
			pr_err("%pOF: Couldn't find opp node\n", cpu_np);
			ret = -ENOENT;
			goto put_cpu_node;
		}

		/* CPUs are sharing opp node */
		if (np == tmp_np)
			cpumask_set_cpu(cpu, cpumask);

		of_node_put(tmp_np);
	}

put_cpu_node:
	of_node_put(np);
	return ret;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_get_sharing_cpus);

/**
 * of_get_required_opp_performance_state() - Search for required OPP and return its performance state.
 * @np: Node that contains the "required-opps" property.
 * @index: Index of the phandle to parse.
 *
 * Returns the performance state of the OPP pointed out by the "required-opps"
 * property at @index in @np.
 *
 * Return: Zero or positive performance state on success, otherwise negative
 * value on errors.
 */
int of_get_required_opp_performance_state(struct device_node *np, int index)
{
	struct dev_pm_opp *opp;
	struct device_node *required_np;
	struct opp_table *opp_table;
	int pstate = -EINVAL;

	required_np = of_parse_required_opp(np, index);
	if (!required_np)
		return -ENODEV;

	opp_table = _find_table_of_opp_np(required_np);
	if (IS_ERR(opp_table)) {
		pr_err("%s: Failed to find required OPP table %pOF: %ld\n",
		       __func__, np, PTR_ERR(opp_table));
		goto put_required_np;
	}

	/* The OPP tables must belong to a genpd */
	if (unlikely(!opp_table->is_genpd)) {
		pr_err("%s: Performance state is only valid for genpds.\n", __func__);
		goto put_required_np;
	}

	opp = _find_opp_of_np(opp_table, required_np);
	if (opp) {
		if (opp->level == OPP_LEVEL_UNSET) {
			pr_err("%s: OPP levels aren't available for %pOF\n",
			       __func__, np);
		} else {
			pstate = opp->level;
		}
		dev_pm_opp_put(opp);

	}

	dev_pm_opp_put_opp_table(opp_table);

put_required_np:
	of_node_put(required_np);

	return pstate;
}
EXPORT_SYMBOL_GPL(of_get_required_opp_performance_state);

/**
 * dev_pm_opp_of_has_required_opp - Find out if a required-opps exists.
 * @dev: The device to investigate.
 *
 * Returns true if the device's node has a "operating-points-v2" property and if
 * the corresponding node for the opp-table describes opp nodes that uses the
 * "required-opps" property.
 *
 * Return: True if a required-opps is present, else false.
 */
bool dev_pm_opp_of_has_required_opp(struct device *dev)
{
	struct device_node *opp_np, *np;
	int count;

	opp_np = _opp_of_get_opp_desc_node(dev->of_node, 0);
	if (!opp_np)
		return false;

	np = of_get_next_available_child(opp_np, NULL);
	of_node_put(opp_np);
	if (!np) {
		dev_warn(dev, "Empty OPP table\n");
		return false;
	}

	count = of_count_phandle_with_args(np, "required-opps", NULL);
	of_node_put(np);

	return count > 0;
}

/**
 * dev_pm_opp_get_of_node() - Gets the DT node corresponding to an opp
 * @opp:	opp for which DT node has to be returned for
 *
 * Return: DT node corresponding to the opp, else 0 on success.
 *
 * The caller needs to put the node with of_node_put() after using it.
 */
struct device_node *dev_pm_opp_get_of_node(struct dev_pm_opp *opp)
{
	if (IS_ERR_OR_NULL(opp)) {
		pr_err("%s: Invalid parameters\n", __func__);
		return NULL;
	}

	return of_node_get(opp->np);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_get_of_node);

/*
 * Callback function provided to the Energy Model framework upon registration.
 * It provides the power used by @dev at @kHz if it is the frequency of an
 * existing OPP, or at the frequency of the first OPP above @kHz otherwise
 * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
 * frequency and @uW to the associated power.
 *
 * Returns 0 on success or a proper -EINVAL value in case of error.
 */
static int __maybe_unused
_get_dt_power(struct device *dev, unsigned long *uW, unsigned long *kHz)
{
	struct dev_pm_opp *opp;
	unsigned long opp_freq, opp_power;

	/* Find the right frequency and related OPP */
	opp_freq = *kHz * 1000;
	opp = dev_pm_opp_find_freq_ceil(dev, &opp_freq);
	if (IS_ERR(opp))
		return -EINVAL;

	opp_power = dev_pm_opp_get_power(opp);
	dev_pm_opp_put(opp);
	if (!opp_power)
		return -EINVAL;

	*kHz = opp_freq / 1000;
	*uW = opp_power;

	return 0;
}

/**
 * dev_pm_opp_calc_power() - Calculate power value for device with EM
 * @dev		: Device for which an Energy Model has to be registered
 * @uW		: New power value that is calculated
 * @kHz		: Frequency for which the new power is calculated
 *
 * This computes the power estimated by @dev at @kHz if it is the frequency
 * of an existing OPP, or at the frequency of the first OPP above @kHz otherwise
 * (see dev_pm_opp_find_freq_ceil()). This function updates @kHz to the ceiled
 * frequency and @uW to the associated power. The power is estimated as
 * P = C * V^2 * f with C being the device's capacitance and V and f
 * respectively the voltage and frequency of the OPP.
 * It is also used as a callback function provided to the Energy Model
 * framework upon registration.
 *
 * Returns -EINVAL if the power calculation failed because of missing
 * parameters, 0 otherwise.
 */
int dev_pm_opp_calc_power(struct device *dev, unsigned long *uW,
			  unsigned long *kHz)
{
	struct dev_pm_opp *opp;
	struct device_node *np;
	unsigned long mV, Hz;
	u32 cap;
	u64 tmp;
	int ret;

	np = of_node_get(dev->of_node);
	if (!np)
		return -EINVAL;

	ret = of_property_read_u32(np, "dynamic-power-coefficient", &cap);
	of_node_put(np);
	if (ret)
		return -EINVAL;

	Hz = *kHz * 1000;
	opp = dev_pm_opp_find_freq_ceil(dev, &Hz);
	if (IS_ERR(opp))
		return -EINVAL;

	mV = dev_pm_opp_get_voltage(opp) / 1000;
	dev_pm_opp_put(opp);
	if (!mV)
		return -EINVAL;

	tmp = (u64)cap * mV * mV * (Hz / 1000000);
	/* Provide power in micro-Watts */
	do_div(tmp, 1000000);

	*uW = (unsigned long)tmp;
	*kHz = Hz / 1000;

	return 0;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_calc_power);

static bool _of_has_opp_microwatt_property(struct device *dev)
{
	unsigned long power, freq = 0;
	struct dev_pm_opp *opp;

	/* Check if at least one OPP has needed property */
	opp = dev_pm_opp_find_freq_ceil(dev, &freq);
	if (IS_ERR(opp))
		return false;

	power = dev_pm_opp_get_power(opp);
	dev_pm_opp_put(opp);
	if (!power)
		return false;

	return true;
}

/**
 * dev_pm_opp_of_register_em() - Attempt to register an Energy Model
 * @dev		: Device for which an Energy Model has to be registered
 * @cpus	: CPUs for which an Energy Model has to be registered. For
 *		other type of devices it should be set to NULL.
 *
 * This checks whether the "dynamic-power-coefficient" devicetree property has
 * been specified, and tries to register an Energy Model with it if it has.
 * Having this property means the voltages are known for OPPs and the EM
 * might be calculated.
 */
int dev_pm_opp_of_register_em(struct device *dev, struct cpumask *cpus)
{
	struct em_data_callback em_cb;
	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;
	}

	/* First, try to find more precised Energy Model in DT */
	if (_of_has_opp_microwatt_property(dev)) {
		EM_SET_ACTIVE_POWER_CB(em_cb, _get_dt_power);
		goto register_em;
	}

	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;
	}

	EM_SET_ACTIVE_POWER_CB(em_cb, dev_pm_opp_calc_power);

register_em:
	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;
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_register_em);