Linux 4.19.133

[linux/fpc-iii.git] / drivers / opp / of.c

/*
 * Generic OPP OF helpers
 *
 * Copyright (C) 2009-2010 Texas Instruments Incorporated.
 *      Nishanth Menon
 *      Romit Dasgupta
 *      Kevin Hilman
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

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

#include "opp.h"

static struct opp_table *_managed_opp(const struct device_node *np)
{
        struct opp_table *opp_table, *managed_table = NULL;

        mutex_lock(&opp_table_lock);

        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;
                }
        }

        mutex_unlock(&opp_table_lock);

        return managed_table;
}

void _of_init_opp_table(struct opp_table *opp_table, struct device *dev)
{
        struct device_node *np;

        /*
         * 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) {
                u32 val;

                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);
                of_node_put(np);
        }
}

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

        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_find_property(np, "opp-supported-hw", NULL))
                        return false;
                else
                        return true;
        }

        while (count--) {
                ret = of_property_read_u32_index(np, "opp-supported-hw", count,
                                                 &version);
                if (ret) {
                        dev_warn(dev, "%s: failed to read opp-supported-hw property at index %d: %d\n",
                                 __func__, count, ret);
                        return false;
                }

                /* Both of these are bitwise masks of the versions */
                if (!(version & opp_table->supported_hw[count]))
                        return false;
        }

        return true;
}

static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
                              struct opp_table *opp_table)
{
        u32 *microvolt, *microamp = NULL;
        int supplies = opp_table->regulator_count, vcount, icount, ret, i, j;
        struct property *prop = NULL;
        char name[NAME_MAX];

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

        if (!prop) {
                /* Search for "opp-microvolt" */
                sprintf(name, "opp-microvolt");
                prop = of_find_property(opp->np, name, NULL);

                /* Missing property isn't a problem, but an invalid entry is */
                if (!prop) {
                        if (unlikely(supplies == -1)) {
                                /* Initialize regulator_count */
                                opp_table->regulator_count = 0;
                                return 0;
                        }

                        if (!supplies)
                                return 0;

                        dev_err(dev, "%s: opp-microvolt missing although OPP managing regulators\n",
                                __func__);
                        return -EINVAL;
                }
        }

        if (unlikely(supplies == -1)) {
                /* Initialize regulator_count */
                supplies = opp_table->regulator_count = 1;
        } else if (unlikely(!supplies)) {
                dev_err(dev, "%s: opp-microvolt wasn't expected\n", __func__);
                return -EINVAL;
        }

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

        /* There can be one or three elements per supply */
        if (vcount != supplies && vcount != supplies * 3) {
                dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
                        __func__, name, vcount, supplies);
                return -EINVAL;
        }

        microvolt = kmalloc_array(vcount, sizeof(*microvolt), GFP_KERNEL);
        if (!microvolt)
                return -ENOMEM;

        ret = of_property_read_u32_array(opp->np, name, microvolt, vcount);
        if (ret) {
                dev_err(dev, "%s: error parsing %s: %d\n", __func__, name, ret);
                ret = -EINVAL;
                goto free_microvolt;
        }

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

        if (!prop) {
                /* Search for "opp-microamp" */
                sprintf(name, "opp-microamp");
                prop = of_find_property(opp->np, name, NULL);
        }

        if (prop) {
                icount = of_property_count_u32_elems(opp->np, name);
                if (icount < 0) {
                        dev_err(dev, "%s: Invalid %s property (%d)\n", __func__,
                                name, icount);
                        ret = icount;
                        goto free_microvolt;
                }

                if (icount != supplies) {
                        dev_err(dev, "%s: Invalid number of elements in %s property (%d) with supplies (%d)\n",
                                __func__, name, icount, supplies);
                        ret = -EINVAL;
                        goto free_microvolt;
                }

                microamp = kmalloc_array(icount, sizeof(*microamp), GFP_KERNEL);
                if (!microamp) {
                        ret = -EINVAL;
                        goto free_microvolt;
                }

                ret = of_property_read_u32_array(opp->np, name, microamp,
                                                 icount);
                if (ret) {
                        dev_err(dev, "%s: error parsing %s: %d\n", __func__,
                                name, ret);
                        ret = -EINVAL;
                        goto free_microamp;
                }
        }

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

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

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

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_find_and_remove_table(dev, false);
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);

/* 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);

/**
 * _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:
 * 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
 * -EINVAL      Failed parsing the OPP node
 */
static int _opp_add_static_v2(struct opp_table *opp_table, struct device *dev,
                              struct device_node *np)
{
        struct dev_pm_opp *new_opp;
        u64 rate = 0;
        u32 val;
        int ret;
        bool rate_not_available = false;

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

        ret = of_property_read_u64(np, "opp-hz", &rate);
        if (ret < 0) {
                /* "opp-hz" is optional for devices like power domains. */
                if (!of_find_property(dev->of_node, "#power-domain-cells",
                                      NULL)) {
                        dev_err(dev, "%s: opp-hz not found\n", __func__);
                        goto free_opp;
                }

                rate_not_available = true;
        } 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.
                 */
                new_opp->rate = (unsigned long)rate;
        }

        /* 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: %llu\n", rate);
                goto free_opp;
        }

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

        new_opp->np = np;
        new_opp->dynamic = false;
        new_opp->available = true;

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

        new_opp->pstate = of_genpd_opp_to_performance_state(dev, np);

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

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

        /* OPP to select on device suspend */
        if (of_property_read_bool(np, "opp-suspend")) {
                if (opp_table->suspend_opp) {
                        dev_warn(dev, "%s: Multiple suspend OPPs found (%lu %lu)\n",
                                 __func__, opp_table->suspend_opp->rate,
                                 new_opp->rate);
                } 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\n",
                 __func__, new_opp->turbo, new_opp->rate,
                 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);

        /*
         * 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 0;

free_opp:
        _opp_free(new_opp);

        return ret;
}

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

        opp_table = _managed_opp(opp_np);
        if (opp_table) {
                /* OPPs are already managed */
                if (!_add_opp_dev(dev, opp_table))
                        ret = -ENOMEM;
                goto put_opp_table;
        }

        opp_table = dev_pm_opp_get_opp_table(dev);
        if (!opp_table)
                return -ENOMEM;

        /* We have opp-table node now, iterate over it and add OPPs */
        for_each_available_child_of_node(opp_np, np) {
                count++;

                ret = _opp_add_static_v2(opp_table, dev, np);
                if (ret) {
                        dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
                                ret);
                        _dev_pm_opp_remove_table(opp_table, dev, false);
                        of_node_put(np);
                        goto put_opp_table;
                }
        }

        /* There should be one of more OPP defined */
        if (WARN_ON(!count)) {
                ret = -ENOENT;
                goto put_opp_table;
        }

        list_for_each_entry(opp, &opp_table->opp_list, node)
                pstate_count += !!opp->pstate;

        /* Either all or none of the nodes shall have performance state set */
        if (pstate_count && pstate_count != count) {
                dev_err(dev, "Not all nodes have performance state set (%d: %d)\n",
                        count, pstate_count);
                ret = -ENOENT;
                _dev_pm_opp_remove_table(opp_table, dev, false);
                goto put_opp_table;
        }

        if (pstate_count)
                opp_table->genpd_performance_state = true;

        opp_table->np = opp_np;
        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;

put_opp_table:
        dev_pm_opp_put_opp_table(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;

        prop = of_find_property(dev->of_node, "operating-points", NULL);
        if (!prop)
                return -ENODEV;
        if (!prop->value)
                return -ENODATA;

        /*
         * 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__);
                return -EINVAL;
        }

        opp_table = dev_pm_opp_get_opp_table(dev);
        if (!opp_table)
                return -ENOMEM;

        val = prop->value;
        while (nr) {
                unsigned long freq = be32_to_cpup(val++) * 1000;
                unsigned long volt = be32_to_cpup(val++);

                ret = _opp_add_v1(opp_table, dev, freq, volt, false);
                if (ret) {
                        dev_err(dev, "%s: Failed to add OPP %ld (%d)\n",
                                __func__, freq, ret);
                        _dev_pm_opp_remove_table(opp_table, dev, false);
                        break;
                }
                nr -= 2;
        }

        dev_pm_opp_put_opp_table(opp_table);
        return ret;
}

/**
 * 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)
{
        struct device_node *opp_np;
        int ret;

        /*
         * OPPs have two version of bindings now. The older one is deprecated,
         * try for the new binding first.
         */
        opp_np = dev_pm_opp_of_get_opp_desc_node(dev);
        if (!opp_np) {
                /*
                 * Try old-deprecated bindings for backward compatibility with
                 * older dtbs.
                 */
                return _of_add_opp_table_v1(dev);
        }

        ret = _of_add_opp_table_v2(dev, opp_np);
        of_node_put(opp_np);

        return ret;
}
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:
 * 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_indexed(struct device *dev, int index)
{
        struct device_node *opp_np;
        int ret, count;

again:
        opp_np = _opp_of_get_opp_desc_node(dev->of_node, index);
        if (!opp_np) {
                /*
                 * 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) {
                        index = 0;
                        goto again;
                }

                return -ENODEV;
        }

        ret = _of_add_opp_table_v2(dev, opp_np);
        of_node_put(opp_np);

        return ret;
}
EXPORT_SYMBOL_GPL(dev_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, true);
}
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 = 0;

        WARN_ON(cpumask_empty(cpumask));

        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);
                        continue;
                }

                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);

                        /* Free all other OPPs */
                        dev_pm_opp_of_cpumask_remove_table(cpumask);
                        break;
                }
        }

        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_dev_pm_opp_find_required_opp() - Search for required OPP.
 * @dev: The device whose OPP node is referenced by the 'np' DT node.
 * @np: Node that contains the "required-opps" property.
 *
 * Returns the OPP of the device 'dev', whose phandle is present in the "np"
 * node. Although the "required-opps" property supports having multiple
 * phandles, this helper routine only parses the very first phandle in the list.
 *
 * Return: Matching opp, else returns ERR_PTR in case of error and should be
 * handled using IS_ERR.
 *
 * The callers are required to call dev_pm_opp_put() for the returned OPP after
 * use.
 */
struct dev_pm_opp *of_dev_pm_opp_find_required_opp(struct device *dev,
                                                   struct device_node *np)
{
        struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ENODEV);
        struct device_node *required_np;
        struct opp_table *opp_table;

        opp_table = _find_opp_table(dev);
        if (IS_ERR(opp_table))
                return ERR_CAST(opp_table);

        required_np = of_parse_phandle(np, "required-opps", 0);
        if (unlikely(!required_np)) {
                dev_err(dev, "Unable to parse required-opps\n");
                goto put_opp_table;
        }

        mutex_lock(&opp_table->lock);

        list_for_each_entry(temp_opp, &opp_table->opp_list, node) {
                if (temp_opp->available && temp_opp->np == required_np) {
                        opp = temp_opp;

                        /* Increment the reference count of OPP */
                        dev_pm_opp_get(opp);
                        break;
                }
        }

        mutex_unlock(&opp_table->lock);

        of_node_put(required_np);
put_opp_table:
        dev_pm_opp_put_opp_table(opp_table);

        return opp;
}
EXPORT_SYMBOL_GPL(of_dev_pm_opp_find_required_opp);

/**
 * 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);