Merge tag 'block-5.11-2021-01-10' of git://git.kernel.dk/linux-block

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

// SPDX-License-Identifier: GPL-2.0+
/*
 * drivers/of/property.c - Procedures for accessing and interpreting
 *                         Devicetree properties and graphs.
 *
 * Initially created by copying procedures from drivers/of/base.c. This
 * file contains the OF property as well as the OF graph interface
 * functions.
 *
 * Paul Mackerras       August 1996.
 * Copyright (C) 1996-2005 Paul Mackerras.
 *
 *  Adapted for 64bit PowerPC by Dave Engebretsen and Peter Bergner.
 *    {engebret|bergner}@us.ibm.com
 *
 *  Adapted for sparc and sparc64 by David S. Miller davem@davemloft.net
 *
 *  Reconsolidated from arch/x/kernel/prom.c by Stephen Rothwell and
 *  Grant Likely.
 */

#define pr_fmt(fmt)     "OF: " fmt

#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/of_graph.h>
#include <linux/string.h>
#include <linux/moduleparam.h>

#include "of_private.h"

/**
 * of_graph_is_present() - check graph's presence
 * @node: pointer to device_node containing graph port
 *
 * Return: True if @node has a port or ports (with a port) sub-node,
 * false otherwise.
 */
bool of_graph_is_present(const struct device_node *node)
{
        struct device_node *ports, *port;

        ports = of_get_child_by_name(node, "ports");
        if (ports)
                node = ports;

        port = of_get_child_by_name(node, "port");
        of_node_put(ports);
        of_node_put(port);

        return !!port;
}
EXPORT_SYMBOL(of_graph_is_present);

/**
 * of_property_count_elems_of_size - Count the number of elements in a property
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @elem_size:  size of the individual element
 *
 * Search for a property in a device node and count the number of elements of
 * size elem_size in it. Returns number of elements on sucess, -EINVAL if the
 * property does not exist or its length does not match a multiple of elem_size
 * and -ENODATA if the property does not have a value.
 */
int of_property_count_elems_of_size(const struct device_node *np,
                                const char *propname, int elem_size)
{
        struct property *prop = of_find_property(np, propname, NULL);

        if (!prop)
                return -EINVAL;
        if (!prop->value)
                return -ENODATA;

        if (prop->length % elem_size != 0) {
                pr_err("size of %s in node %pOF is not a multiple of %d\n",
                       propname, np, elem_size);
                return -EINVAL;
        }

        return prop->length / elem_size;
}
EXPORT_SYMBOL_GPL(of_property_count_elems_of_size);

/**
 * of_find_property_value_of_size
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @min:        minimum allowed length of property value
 * @max:        maximum allowed length of property value (0 means unlimited)
 * @len:        if !=NULL, actual length is written to here
 *
 * Search for a property in a device node and valid the requested size.
 * Returns the property value on success, -EINVAL if the property does not
 *  exist, -ENODATA if property does not have a value, and -EOVERFLOW if the
 * property data is too small or too large.
 *
 */
static void *of_find_property_value_of_size(const struct device_node *np,
                        const char *propname, u32 min, u32 max, size_t *len)
{
        struct property *prop = of_find_property(np, propname, NULL);

        if (!prop)
                return ERR_PTR(-EINVAL);
        if (!prop->value)
                return ERR_PTR(-ENODATA);
        if (prop->length < min)
                return ERR_PTR(-EOVERFLOW);
        if (max && prop->length > max)
                return ERR_PTR(-EOVERFLOW);

        if (len)
                *len = prop->length;

        return prop->value;
}

/**
 * of_property_read_u32_index - Find and read a u32 from a multi-value property.
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @index:      index of the u32 in the list of values
 * @out_value:  pointer to return value, modified only if no error.
 *
 * Search for a property in a device node and read nth 32-bit value from
 * it. Returns 0 on success, -EINVAL if the property does not exist,
 * -ENODATA if property does not have a value, and -EOVERFLOW if the
 * property data isn't large enough.
 *
 * The out_value is modified only if a valid u32 value can be decoded.
 */
int of_property_read_u32_index(const struct device_node *np,
                                       const char *propname,
                                       u32 index, u32 *out_value)
{
        const u32 *val = of_find_property_value_of_size(np, propname,
                                        ((index + 1) * sizeof(*out_value)),
                                        0,
                                        NULL);

        if (IS_ERR(val))
                return PTR_ERR(val);

        *out_value = be32_to_cpup(((__be32 *)val) + index);
        return 0;
}
EXPORT_SYMBOL_GPL(of_property_read_u32_index);

/**
 * of_property_read_u64_index - Find and read a u64 from a multi-value property.
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @index:      index of the u64 in the list of values
 * @out_value:  pointer to return value, modified only if no error.
 *
 * Search for a property in a device node and read nth 64-bit value from
 * it. Returns 0 on success, -EINVAL if the property does not exist,
 * -ENODATA if property does not have a value, and -EOVERFLOW if the
 * property data isn't large enough.
 *
 * The out_value is modified only if a valid u64 value can be decoded.
 */
int of_property_read_u64_index(const struct device_node *np,
                                       const char *propname,
                                       u32 index, u64 *out_value)
{
        const u64 *val = of_find_property_value_of_size(np, propname,
                                        ((index + 1) * sizeof(*out_value)),
                                        0, NULL);

        if (IS_ERR(val))
                return PTR_ERR(val);

        *out_value = be64_to_cpup(((__be64 *)val) + index);
        return 0;
}
EXPORT_SYMBOL_GPL(of_property_read_u64_index);

/**
 * of_property_read_variable_u8_array - Find and read an array of u8 from a
 * property, with bounds on the minimum and maximum array size.
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @out_values: pointer to found values.
 * @sz_min:     minimum number of array elements to read
 * @sz_max:     maximum number of array elements to read, if zero there is no
 *              upper limit on the number of elements in the dts entry but only
 *              sz_min will be read.
 *
 * Search for a property in a device node and read 8-bit value(s) from
 * it. Returns number of elements read on success, -EINVAL if the property
 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
 * if the property data is smaller than sz_min or longer than sz_max.
 *
 * dts entry of array should be like:
 *      property = /bits/ 8 <0x50 0x60 0x70>;
 *
 * The out_values is modified only if a valid u8 value can be decoded.
 */
int of_property_read_variable_u8_array(const struct device_node *np,
                                        const char *propname, u8 *out_values,
                                        size_t sz_min, size_t sz_max)
{
        size_t sz, count;
        const u8 *val = of_find_property_value_of_size(np, propname,
                                                (sz_min * sizeof(*out_values)),
                                                (sz_max * sizeof(*out_values)),
                                                &sz);

        if (IS_ERR(val))
                return PTR_ERR(val);

        if (!sz_max)
                sz = sz_min;
        else
                sz /= sizeof(*out_values);

        count = sz;
        while (count--)
                *out_values++ = *val++;

        return sz;
}
EXPORT_SYMBOL_GPL(of_property_read_variable_u8_array);

/**
 * of_property_read_variable_u16_array - Find and read an array of u16 from a
 * property, with bounds on the minimum and maximum array size.
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @out_values: pointer to found values.
 * @sz_min:     minimum number of array elements to read
 * @sz_max:     maximum number of array elements to read, if zero there is no
 *              upper limit on the number of elements in the dts entry but only
 *              sz_min will be read.
 *
 * Search for a property in a device node and read 16-bit value(s) from
 * it. Returns number of elements read on success, -EINVAL if the property
 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
 * if the property data is smaller than sz_min or longer than sz_max.
 *
 * dts entry of array should be like:
 *      property = /bits/ 16 <0x5000 0x6000 0x7000>;
 *
 * The out_values is modified only if a valid u16 value can be decoded.
 */
int of_property_read_variable_u16_array(const struct device_node *np,
                                        const char *propname, u16 *out_values,
                                        size_t sz_min, size_t sz_max)
{
        size_t sz, count;
        const __be16 *val = of_find_property_value_of_size(np, propname,
                                                (sz_min * sizeof(*out_values)),
                                                (sz_max * sizeof(*out_values)),
                                                &sz);

        if (IS_ERR(val))
                return PTR_ERR(val);

        if (!sz_max)
                sz = sz_min;
        else
                sz /= sizeof(*out_values);

        count = sz;
        while (count--)
                *out_values++ = be16_to_cpup(val++);

        return sz;
}
EXPORT_SYMBOL_GPL(of_property_read_variable_u16_array);

/**
 * of_property_read_variable_u32_array - Find and read an array of 32 bit
 * integers from a property, with bounds on the minimum and maximum array size.
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @out_values: pointer to return found values.
 * @sz_min:     minimum number of array elements to read
 * @sz_max:     maximum number of array elements to read, if zero there is no
 *              upper limit on the number of elements in the dts entry but only
 *              sz_min will be read.
 *
 * Search for a property in a device node and read 32-bit value(s) from
 * it. Returns number of elements read on success, -EINVAL if the property
 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
 * if the property data is smaller than sz_min or longer than sz_max.
 *
 * The out_values is modified only if a valid u32 value can be decoded.
 */
int of_property_read_variable_u32_array(const struct device_node *np,
                               const char *propname, u32 *out_values,
                               size_t sz_min, size_t sz_max)
{
        size_t sz, count;
        const __be32 *val = of_find_property_value_of_size(np, propname,
                                                (sz_min * sizeof(*out_values)),
                                                (sz_max * sizeof(*out_values)),
                                                &sz);

        if (IS_ERR(val))
                return PTR_ERR(val);

        if (!sz_max)
                sz = sz_min;
        else
                sz /= sizeof(*out_values);

        count = sz;
        while (count--)
                *out_values++ = be32_to_cpup(val++);

        return sz;
}
EXPORT_SYMBOL_GPL(of_property_read_variable_u32_array);

/**
 * of_property_read_u64 - Find and read a 64 bit integer from a property
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @out_value:  pointer to return value, modified only if return value is 0.
 *
 * Search for a property in a device node and read a 64-bit value from
 * it. Returns 0 on success, -EINVAL if the property does not exist,
 * -ENODATA if property does not have a value, and -EOVERFLOW if the
 * property data isn't large enough.
 *
 * The out_value is modified only if a valid u64 value can be decoded.
 */
int of_property_read_u64(const struct device_node *np, const char *propname,
                         u64 *out_value)
{
        const __be32 *val = of_find_property_value_of_size(np, propname,
                                                sizeof(*out_value),
                                                0,
                                                NULL);

        if (IS_ERR(val))
                return PTR_ERR(val);

        *out_value = of_read_number(val, 2);
        return 0;
}
EXPORT_SYMBOL_GPL(of_property_read_u64);

/**
 * of_property_read_variable_u64_array - Find and read an array of 64 bit
 * integers from a property, with bounds on the minimum and maximum array size.
 *
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @out_values: pointer to found values.
 * @sz_min:     minimum number of array elements to read
 * @sz_max:     maximum number of array elements to read, if zero there is no
 *              upper limit on the number of elements in the dts entry but only
 *              sz_min will be read.
 *
 * Search for a property in a device node and read 64-bit value(s) from
 * it. Returns number of elements read on success, -EINVAL if the property
 * does not exist, -ENODATA if property does not have a value, and -EOVERFLOW
 * if the property data is smaller than sz_min or longer than sz_max.
 *
 * The out_values is modified only if a valid u64 value can be decoded.
 */
int of_property_read_variable_u64_array(const struct device_node *np,
                               const char *propname, u64 *out_values,
                               size_t sz_min, size_t sz_max)
{
        size_t sz, count;
        const __be32 *val = of_find_property_value_of_size(np, propname,
                                                (sz_min * sizeof(*out_values)),
                                                (sz_max * sizeof(*out_values)),
                                                &sz);

        if (IS_ERR(val))
                return PTR_ERR(val);

        if (!sz_max)
                sz = sz_min;
        else
                sz /= sizeof(*out_values);

        count = sz;
        while (count--) {
                *out_values++ = of_read_number(val, 2);
                val += 2;
        }

        return sz;
}
EXPORT_SYMBOL_GPL(of_property_read_variable_u64_array);

/**
 * of_property_read_string - Find and read a string from a property
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @out_string: pointer to null terminated return string, modified only if
 *              return value is 0.
 *
 * Search for a property in a device tree node and retrieve a null
 * terminated string value (pointer to data, not a copy). Returns 0 on
 * success, -EINVAL if the property does not exist, -ENODATA if property
 * does not have a value, and -EILSEQ if the string is not null-terminated
 * within the length of the property data.
 *
 * The out_string pointer is modified only if a valid string can be decoded.
 */
int of_property_read_string(const struct device_node *np, const char *propname,
                                const char **out_string)
{
        const struct property *prop = of_find_property(np, propname, NULL);
        if (!prop)
                return -EINVAL;
        if (!prop->value)
                return -ENODATA;
        if (strnlen(prop->value, prop->length) >= prop->length)
                return -EILSEQ;
        *out_string = prop->value;
        return 0;
}
EXPORT_SYMBOL_GPL(of_property_read_string);

/**
 * of_property_match_string() - Find string in a list and return index
 * @np: pointer to node containing string list property
 * @propname: string list property name
 * @string: pointer to string to search for in string list
 *
 * This function searches a string list property and returns the index
 * of a specific string value.
 */
int of_property_match_string(const struct device_node *np, const char *propname,
                             const char *string)
{
        const struct property *prop = of_find_property(np, propname, NULL);
        size_t l;
        int i;
        const char *p, *end;

        if (!prop)
                return -EINVAL;
        if (!prop->value)
                return -ENODATA;

        p = prop->value;
        end = p + prop->length;

        for (i = 0; p < end; i++, p += l) {
                l = strnlen(p, end - p) + 1;
                if (p + l > end)
                        return -EILSEQ;
                pr_debug("comparing %s with %s\n", string, p);
                if (strcmp(string, p) == 0)
                        return i; /* Found it; return index */
        }
        return -ENODATA;
}
EXPORT_SYMBOL_GPL(of_property_match_string);

/**
 * of_property_read_string_helper() - Utility helper for parsing string properties
 * @np:         device node from which the property value is to be read.
 * @propname:   name of the property to be searched.
 * @out_strs:   output array of string pointers.
 * @sz:         number of array elements to read.
 * @skip:       Number of strings to skip over at beginning of list.
 *
 * Don't call this function directly. It is a utility helper for the
 * of_property_read_string*() family of functions.
 */
int of_property_read_string_helper(const struct device_node *np,
                                   const char *propname, const char **out_strs,
                                   size_t sz, int skip)
{
        const struct property *prop = of_find_property(np, propname, NULL);
        int l = 0, i = 0;
        const char *p, *end;

        if (!prop)
                return -EINVAL;
        if (!prop->value)
                return -ENODATA;
        p = prop->value;
        end = p + prop->length;

        for (i = 0; p < end && (!out_strs || i < skip + sz); i++, p += l) {
                l = strnlen(p, end - p) + 1;
                if (p + l > end)
                        return -EILSEQ;
                if (out_strs && i >= skip)
                        *out_strs++ = p;
        }
        i -= skip;
        return i <= 0 ? -ENODATA : i;
}
EXPORT_SYMBOL_GPL(of_property_read_string_helper);

const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
                               u32 *pu)
{
        const void *curv = cur;

        if (!prop)
                return NULL;

        if (!cur) {
                curv = prop->value;
                goto out_val;
        }

        curv += sizeof(*cur);
        if (curv >= prop->value + prop->length)
                return NULL;

out_val:
        *pu = be32_to_cpup(curv);
        return curv;
}
EXPORT_SYMBOL_GPL(of_prop_next_u32);

const char *of_prop_next_string(struct property *prop, const char *cur)
{
        const void *curv = cur;

        if (!prop)
                return NULL;

        if (!cur)
                return prop->value;

        curv += strlen(cur) + 1;
        if (curv >= prop->value + prop->length)
                return NULL;

        return curv;
}
EXPORT_SYMBOL_GPL(of_prop_next_string);

/**
 * of_graph_parse_endpoint() - parse common endpoint node properties
 * @node: pointer to endpoint device_node
 * @endpoint: pointer to the OF endpoint data structure
 *
 * The caller should hold a reference to @node.
 */
int of_graph_parse_endpoint(const struct device_node *node,
                            struct of_endpoint *endpoint)
{
        struct device_node *port_node = of_get_parent(node);

        WARN_ONCE(!port_node, "%s(): endpoint %pOF has no parent node\n",
                  __func__, node);

        memset(endpoint, 0, sizeof(*endpoint));

        endpoint->local_node = node;
        /*
         * It doesn't matter whether the two calls below succeed.
         * If they don't then the default value 0 is used.
         */
        of_property_read_u32(port_node, "reg", &endpoint->port);
        of_property_read_u32(node, "reg", &endpoint->id);

        of_node_put(port_node);

        return 0;
}
EXPORT_SYMBOL(of_graph_parse_endpoint);

/**
 * of_graph_get_port_by_id() - get the port matching a given id
 * @parent: pointer to the parent device node
 * @id: id of the port
 *
 * Return: A 'port' node pointer with refcount incremented. The caller
 * has to use of_node_put() on it when done.
 */
struct device_node *of_graph_get_port_by_id(struct device_node *parent, u32 id)
{
        struct device_node *node, *port;

        node = of_get_child_by_name(parent, "ports");
        if (node)
                parent = node;

        for_each_child_of_node(parent, port) {
                u32 port_id = 0;

                if (!of_node_name_eq(port, "port"))
                        continue;
                of_property_read_u32(port, "reg", &port_id);
                if (id == port_id)
                        break;
        }

        of_node_put(node);

        return port;
}
EXPORT_SYMBOL(of_graph_get_port_by_id);

/**
 * of_graph_get_next_endpoint() - get next endpoint node
 * @parent: pointer to the parent device node
 * @prev: previous endpoint node, or NULL to get first
 *
 * Return: An 'endpoint' node pointer with refcount incremented. Refcount
 * of the passed @prev node is decremented.
 */
struct device_node *of_graph_get_next_endpoint(const struct device_node *parent,
                                        struct device_node *prev)
{
        struct device_node *endpoint;
        struct device_node *port;

        if (!parent)
                return NULL;

        /*
         * Start by locating the port node. If no previous endpoint is specified
         * search for the first port node, otherwise get the previous endpoint
         * parent port node.
         */
        if (!prev) {
                struct device_node *node;

                node = of_get_child_by_name(parent, "ports");
                if (node)
                        parent = node;

                port = of_get_child_by_name(parent, "port");
                of_node_put(node);

                if (!port) {
                        pr_err("graph: no port node found in %pOF\n", parent);
                        return NULL;
                }
        } else {
                port = of_get_parent(prev);
                if (WARN_ONCE(!port, "%s(): endpoint %pOF has no parent node\n",
                              __func__, prev))
                        return NULL;
        }

        while (1) {
                /*
                 * Now that we have a port node, get the next endpoint by
                 * getting the next child. If the previous endpoint is NULL this
                 * will return the first child.
                 */
                endpoint = of_get_next_child(port, prev);
                if (endpoint) {
                        of_node_put(port);
                        return endpoint;
                }

                /* No more endpoints under this port, try the next one. */
                prev = NULL;

                do {
                        port = of_get_next_child(parent, port);
                        if (!port)
                                return NULL;
                } while (!of_node_name_eq(port, "port"));
        }
}
EXPORT_SYMBOL(of_graph_get_next_endpoint);

/**
 * of_graph_get_endpoint_by_regs() - get endpoint node of specific identifiers
 * @parent: pointer to the parent device node
 * @port_reg: identifier (value of reg property) of the parent port node
 * @reg: identifier (value of reg property) of the endpoint node
 *
 * Return: An 'endpoint' node pointer which is identified by reg and at the same
 * is the child of a port node identified by port_reg. reg and port_reg are
 * ignored when they are -1. Use of_node_put() on the pointer when done.
 */
struct device_node *of_graph_get_endpoint_by_regs(
        const struct device_node *parent, int port_reg, int reg)
{
        struct of_endpoint endpoint;
        struct device_node *node = NULL;

        for_each_endpoint_of_node(parent, node) {
                of_graph_parse_endpoint(node, &endpoint);
                if (((port_reg == -1) || (endpoint.port == port_reg)) &&
                        ((reg == -1) || (endpoint.id == reg)))
                        return node;
        }

        return NULL;
}
EXPORT_SYMBOL(of_graph_get_endpoint_by_regs);

/**
 * of_graph_get_remote_endpoint() - get remote endpoint node
 * @node: pointer to a local endpoint device_node
 *
 * Return: Remote endpoint node associated with remote endpoint node linked
 *         to @node. Use of_node_put() on it when done.
 */
struct device_node *of_graph_get_remote_endpoint(const struct device_node *node)
{
        /* Get remote endpoint node. */
        return of_parse_phandle(node, "remote-endpoint", 0);
}
EXPORT_SYMBOL(of_graph_get_remote_endpoint);

/**
 * of_graph_get_port_parent() - get port's parent node
 * @node: pointer to a local endpoint device_node
 *
 * Return: device node associated with endpoint node linked
 *         to @node. Use of_node_put() on it when done.
 */
struct device_node *of_graph_get_port_parent(struct device_node *node)
{
        unsigned int depth;

        if (!node)
                return NULL;

        /*
         * Preserve usecount for passed in node as of_get_next_parent()
         * will do of_node_put() on it.
         */
        of_node_get(node);

        /* Walk 3 levels up only if there is 'ports' node. */
        for (depth = 3; depth && node; depth--) {
                node = of_get_next_parent(node);
                if (depth == 2 && !of_node_name_eq(node, "ports"))
                        break;
        }
        return node;
}
EXPORT_SYMBOL(of_graph_get_port_parent);

/**
 * of_graph_get_remote_port_parent() - get remote port's parent node
 * @node: pointer to a local endpoint device_node
 *
 * Return: Remote device node associated with remote endpoint node linked
 *         to @node. Use of_node_put() on it when done.
 */
struct device_node *of_graph_get_remote_port_parent(
                               const struct device_node *node)
{
        struct device_node *np, *pp;

        /* Get remote endpoint node. */
        np = of_graph_get_remote_endpoint(node);

        pp = of_graph_get_port_parent(np);

        of_node_put(np);

        return pp;
}
EXPORT_SYMBOL(of_graph_get_remote_port_parent);

/**
 * of_graph_get_remote_port() - get remote port node
 * @node: pointer to a local endpoint device_node
 *
 * Return: Remote port node associated with remote endpoint node linked
 *         to @node. Use of_node_put() on it when done.
 */
struct device_node *of_graph_get_remote_port(const struct device_node *node)
{
        struct device_node *np;

        /* Get remote endpoint node. */
        np = of_graph_get_remote_endpoint(node);
        if (!np)
                return NULL;
        return of_get_next_parent(np);
}
EXPORT_SYMBOL(of_graph_get_remote_port);

int of_graph_get_endpoint_count(const struct device_node *np)
{
        struct device_node *endpoint;
        int num = 0;

        for_each_endpoint_of_node(np, endpoint)
                num++;

        return num;
}
EXPORT_SYMBOL(of_graph_get_endpoint_count);

/**
 * of_graph_get_remote_node() - get remote parent device_node for given port/endpoint
 * @node: pointer to parent device_node containing graph port/endpoint
 * @port: identifier (value of reg property) of the parent port node
 * @endpoint: identifier (value of reg property) of the endpoint node
 *
 * Return: Remote device node associated with remote endpoint node linked
 *         to @node. Use of_node_put() on it when done.
 */
struct device_node *of_graph_get_remote_node(const struct device_node *node,
                                             u32 port, u32 endpoint)
{
        struct device_node *endpoint_node, *remote;

        endpoint_node = of_graph_get_endpoint_by_regs(node, port, endpoint);
        if (!endpoint_node) {
                pr_debug("no valid endpoint (%d, %d) for node %pOF\n",
                         port, endpoint, node);
                return NULL;
        }

        remote = of_graph_get_remote_port_parent(endpoint_node);
        of_node_put(endpoint_node);
        if (!remote) {
                pr_debug("no valid remote node\n");
                return NULL;
        }

        if (!of_device_is_available(remote)) {
                pr_debug("not available for remote node\n");
                of_node_put(remote);
                return NULL;
        }

        return remote;
}
EXPORT_SYMBOL(of_graph_get_remote_node);

static struct fwnode_handle *of_fwnode_get(struct fwnode_handle *fwnode)
{
        return of_fwnode_handle(of_node_get(to_of_node(fwnode)));
}

static void of_fwnode_put(struct fwnode_handle *fwnode)
{
        of_node_put(to_of_node(fwnode));
}

static bool of_fwnode_device_is_available(const struct fwnode_handle *fwnode)
{
        return of_device_is_available(to_of_node(fwnode));
}

static bool of_fwnode_property_present(const struct fwnode_handle *fwnode,
                                       const char *propname)
{
        return of_property_read_bool(to_of_node(fwnode), propname);
}

static int of_fwnode_property_read_int_array(const struct fwnode_handle *fwnode,
                                             const char *propname,
                                             unsigned int elem_size, void *val,
                                             size_t nval)
{
        const struct device_node *node = to_of_node(fwnode);

        if (!val)
                return of_property_count_elems_of_size(node, propname,
                                                       elem_size);

        switch (elem_size) {
        case sizeof(u8):
                return of_property_read_u8_array(node, propname, val, nval);
        case sizeof(u16):
                return of_property_read_u16_array(node, propname, val, nval);
        case sizeof(u32):
                return of_property_read_u32_array(node, propname, val, nval);
        case sizeof(u64):
                return of_property_read_u64_array(node, propname, val, nval);
        }

        return -ENXIO;
}

static int
of_fwnode_property_read_string_array(const struct fwnode_handle *fwnode,
                                     const char *propname, const char **val,
                                     size_t nval)
{
        const struct device_node *node = to_of_node(fwnode);

        return val ?
                of_property_read_string_array(node, propname, val, nval) :
                of_property_count_strings(node, propname);
}

static const char *of_fwnode_get_name(const struct fwnode_handle *fwnode)
{
        return kbasename(to_of_node(fwnode)->full_name);
}

static const char *of_fwnode_get_name_prefix(const struct fwnode_handle *fwnode)
{
        /* Root needs no prefix here (its name is "/"). */
        if (!to_of_node(fwnode)->parent)
                return "";

        return "/";
}

static struct fwnode_handle *
of_fwnode_get_parent(const struct fwnode_handle *fwnode)
{
        return of_fwnode_handle(of_get_parent(to_of_node(fwnode)));
}

static struct fwnode_handle *
of_fwnode_get_next_child_node(const struct fwnode_handle *fwnode,
                              struct fwnode_handle *child)
{
        return of_fwnode_handle(of_get_next_available_child(to_of_node(fwnode),
                                                            to_of_node(child)));
}

static struct fwnode_handle *
of_fwnode_get_named_child_node(const struct fwnode_handle *fwnode,
                               const char *childname)
{
        const struct device_node *node = to_of_node(fwnode);
        struct device_node *child;

        for_each_available_child_of_node(node, child)
                if (of_node_name_eq(child, childname))
                        return of_fwnode_handle(child);

        return NULL;
}

static int
of_fwnode_get_reference_args(const struct fwnode_handle *fwnode,
                             const char *prop, const char *nargs_prop,
                             unsigned int nargs, unsigned int index,
                             struct fwnode_reference_args *args)
{
        struct of_phandle_args of_args;
        unsigned int i;
        int ret;

        if (nargs_prop)
                ret = of_parse_phandle_with_args(to_of_node(fwnode), prop,
                                                 nargs_prop, index, &of_args);
        else
                ret = of_parse_phandle_with_fixed_args(to_of_node(fwnode), prop,
                                                       nargs, index, &of_args);
        if (ret < 0)
                return ret;
        if (!args)
                return 0;

        args->nargs = of_args.args_count;
        args->fwnode = of_fwnode_handle(of_args.np);

        for (i = 0; i < NR_FWNODE_REFERENCE_ARGS; i++)
                args->args[i] = i < of_args.args_count ? of_args.args[i] : 0;

        return 0;
}

static struct fwnode_handle *
of_fwnode_graph_get_next_endpoint(const struct fwnode_handle *fwnode,
                                  struct fwnode_handle *prev)
{
        return of_fwnode_handle(of_graph_get_next_endpoint(to_of_node(fwnode),
                                                           to_of_node(prev)));
}

static struct fwnode_handle *
of_fwnode_graph_get_remote_endpoint(const struct fwnode_handle *fwnode)
{
        return of_fwnode_handle(
                of_graph_get_remote_endpoint(to_of_node(fwnode)));
}

static struct fwnode_handle *
of_fwnode_graph_get_port_parent(struct fwnode_handle *fwnode)
{
        struct device_node *np;

        /* Get the parent of the port */
        np = of_get_parent(to_of_node(fwnode));
        if (!np)
                return NULL;

        /* Is this the "ports" node? If not, it's the port parent. */
        if (!of_node_name_eq(np, "ports"))
                return of_fwnode_handle(np);

        return of_fwnode_handle(of_get_next_parent(np));
}

static int of_fwnode_graph_parse_endpoint(const struct fwnode_handle *fwnode,
                                          struct fwnode_endpoint *endpoint)
{
        const struct device_node *node = to_of_node(fwnode);
        struct device_node *port_node = of_get_parent(node);

        endpoint->local_fwnode = fwnode;

        of_property_read_u32(port_node, "reg", &endpoint->port);
        of_property_read_u32(node, "reg", &endpoint->id);

        of_node_put(port_node);

        return 0;
}

static const void *
of_fwnode_device_get_match_data(const struct fwnode_handle *fwnode,
                                const struct device *dev)
{
        return of_device_get_match_data(dev);
}

static bool of_is_ancestor_of(struct device_node *test_ancestor,
                              struct device_node *child)
{
        of_node_get(child);
        while (child) {
                if (child == test_ancestor) {
                        of_node_put(child);
                        return true;
                }
                child = of_get_next_parent(child);
        }
        return false;
}

/**
 * of_link_to_phandle - Add fwnode link to supplier from supplier phandle
 * @con_np: consumer device tree node
 * @sup_np: supplier device tree node
 *
 * Given a phandle to a supplier device tree node (@sup_np), this function
 * finds the device that owns the supplier device tree node and creates a
 * device link from @dev consumer device to the supplier device. This function
 * doesn't create device links for invalid scenarios such as trying to create a
 * link with a parent device as the consumer of its child device. In such
 * cases, it returns an error.
 *
 * Returns:
 * - 0 if fwnode link successfully created to supplier
 * - -EINVAL if the supplier link is invalid and should not be created
 * - -ENODEV if struct device will never be create for supplier
 */
static int of_link_to_phandle(struct device_node *con_np,
                              struct device_node *sup_np)
{
        struct device *sup_dev;
        struct device_node *tmp_np = sup_np;

        of_node_get(sup_np);
        /*
         * Find the device node that contains the supplier phandle.  It may be
         * @sup_np or it may be an ancestor of @sup_np.
         */
        while (sup_np) {

                /* Don't allow linking to a disabled supplier */
                if (!of_device_is_available(sup_np)) {
                        of_node_put(sup_np);
                        sup_np = NULL;
                }

                if (of_find_property(sup_np, "compatible", NULL))
                        break;

                sup_np = of_get_next_parent(sup_np);
        }

        if (!sup_np) {
                pr_debug("Not linking %pOFP to %pOFP - No device\n",
                         con_np, tmp_np);
                return -ENODEV;
        }

        /*
         * Don't allow linking a device node as a consumer of one of its
         * descendant nodes. By definition, a child node can't be a functional
         * dependency for the parent node.
         */
        if (of_is_ancestor_of(con_np, sup_np)) {
                pr_debug("Not linking %pOFP to %pOFP - is descendant\n",
                         con_np, sup_np);
                of_node_put(sup_np);
                return -EINVAL;
        }

        /*
         * Don't create links to "early devices" that won't have struct devices
         * created for them.
         */
        sup_dev = get_dev_from_fwnode(&sup_np->fwnode);
        if (!sup_dev && of_node_check_flag(sup_np, OF_POPULATED)) {
                pr_debug("Not linking %pOFP to %pOFP - No struct device\n",
                         con_np, sup_np);
                of_node_put(sup_np);
                return -ENODEV;
        }
        put_device(sup_dev);

        fwnode_link_add(of_fwnode_handle(con_np), of_fwnode_handle(sup_np));
        of_node_put(sup_np);

        return 0;
}

/**
 * parse_prop_cells - Property parsing function for suppliers
 *
 * @np:         Pointer to device tree node containing a list
 * @prop_name:  Name of property to be parsed. Expected to hold phandle values
 * @index:      For properties holding a list of phandles, this is the index
 *              into the list.
 * @list_name:  Property name that is known to contain list of phandle(s) to
 *              supplier(s)
 * @cells_name: property name that specifies phandles' arguments count
 *
 * This is a helper function to parse properties that have a known fixed name
 * and are a list of phandles and phandle arguments.
 *
 * Returns:
 * - phandle node pointer with refcount incremented. Caller must of_node_put()
 *   on it when done.
 * - NULL if no phandle found at index
 */
static struct device_node *parse_prop_cells(struct device_node *np,
                                            const char *prop_name, int index,
                                            const char *list_name,
                                            const char *cells_name)
{
        struct of_phandle_args sup_args;

        if (strcmp(prop_name, list_name))
                return NULL;

        if (of_parse_phandle_with_args(np, list_name, cells_name, index,
                                       &sup_args))
                return NULL;

        return sup_args.np;
}

#define DEFINE_SIMPLE_PROP(fname, name, cells)                            \
static struct device_node *parse_##fname(struct device_node *np,          \
                                        const char *prop_name, int index) \
{                                                                         \
        return parse_prop_cells(np, prop_name, index, name, cells);       \
}

static int strcmp_suffix(const char *str, const char *suffix)
{
        unsigned int len, suffix_len;

        len = strlen(str);
        suffix_len = strlen(suffix);
        if (len <= suffix_len)
                return -1;
        return strcmp(str + len - suffix_len, suffix);
}

/**
 * parse_suffix_prop_cells - Suffix property parsing function for suppliers
 *
 * @np:         Pointer to device tree node containing a list
 * @prop_name:  Name of property to be parsed. Expected to hold phandle values
 * @index:      For properties holding a list of phandles, this is the index
 *              into the list.
 * @suffix:     Property suffix that is known to contain list of phandle(s) to
 *              supplier(s)
 * @cells_name: property name that specifies phandles' arguments count
 *
 * This is a helper function to parse properties that have a known fixed suffix
 * and are a list of phandles and phandle arguments.
 *
 * Returns:
 * - phandle node pointer with refcount incremented. Caller must of_node_put()
 *   on it when done.
 * - NULL if no phandle found at index
 */
static struct device_node *parse_suffix_prop_cells(struct device_node *np,
                                            const char *prop_name, int index,
                                            const char *suffix,
                                            const char *cells_name)
{
        struct of_phandle_args sup_args;

        if (strcmp_suffix(prop_name, suffix))
                return NULL;

        if (of_parse_phandle_with_args(np, prop_name, cells_name, index,
                                       &sup_args))
                return NULL;

        return sup_args.np;
}

#define DEFINE_SUFFIX_PROP(fname, suffix, cells)                             \
static struct device_node *parse_##fname(struct device_node *np,             \
                                        const char *prop_name, int index)    \
{                                                                            \
        return parse_suffix_prop_cells(np, prop_name, index, suffix, cells); \
}

/**
 * struct supplier_bindings - Property parsing functions for suppliers
 *
 * @parse_prop: function name
 *      parse_prop() finds the node corresponding to a supplier phandle
 * @parse_prop.np: Pointer to device node holding supplier phandle property
 * @parse_prop.prop_name: Name of property holding a phandle value
 * @parse_prop.index: For properties holding a list of phandles, this is the
 *                    index into the list
 *
 * Returns:
 * parse_prop() return values are
 * - phandle node pointer with refcount incremented. Caller must of_node_put()
 *   on it when done.
 * - NULL if no phandle found at index
 */
struct supplier_bindings {
        struct device_node *(*parse_prop)(struct device_node *np,
                                          const char *prop_name, int index);
};

DEFINE_SIMPLE_PROP(clocks, "clocks", "#clock-cells")
DEFINE_SIMPLE_PROP(interconnects, "interconnects", "#interconnect-cells")
DEFINE_SIMPLE_PROP(iommus, "iommus", "#iommu-cells")
DEFINE_SIMPLE_PROP(mboxes, "mboxes", "#mbox-cells")
DEFINE_SIMPLE_PROP(io_channels, "io-channel", "#io-channel-cells")
DEFINE_SIMPLE_PROP(interrupt_parent, "interrupt-parent", NULL)
DEFINE_SIMPLE_PROP(dmas, "dmas", "#dma-cells")
DEFINE_SIMPLE_PROP(power_domains, "power-domains", "#power-domain-cells")
DEFINE_SIMPLE_PROP(hwlocks, "hwlocks", "#hwlock-cells")
DEFINE_SIMPLE_PROP(extcon, "extcon", NULL)
DEFINE_SIMPLE_PROP(interrupts_extended, "interrupts-extended",
                                        "#interrupt-cells")
DEFINE_SIMPLE_PROP(nvmem_cells, "nvmem-cells", NULL)
DEFINE_SIMPLE_PROP(phys, "phys", "#phy-cells")
DEFINE_SIMPLE_PROP(wakeup_parent, "wakeup-parent", NULL)
DEFINE_SIMPLE_PROP(pinctrl0, "pinctrl-0", NULL)
DEFINE_SIMPLE_PROP(pinctrl1, "pinctrl-1", NULL)
DEFINE_SIMPLE_PROP(pinctrl2, "pinctrl-2", NULL)
DEFINE_SIMPLE_PROP(pinctrl3, "pinctrl-3", NULL)
DEFINE_SIMPLE_PROP(pinctrl4, "pinctrl-4", NULL)
DEFINE_SIMPLE_PROP(pinctrl5, "pinctrl-5", NULL)
DEFINE_SIMPLE_PROP(pinctrl6, "pinctrl-6", NULL)
DEFINE_SIMPLE_PROP(pinctrl7, "pinctrl-7", NULL)
DEFINE_SIMPLE_PROP(pinctrl8, "pinctrl-8", NULL)
DEFINE_SUFFIX_PROP(regulators, "-supply", NULL)
DEFINE_SUFFIX_PROP(gpio, "-gpio", "#gpio-cells")
DEFINE_SUFFIX_PROP(gpios, "-gpios", "#gpio-cells")

static struct device_node *parse_iommu_maps(struct device_node *np,
                                            const char *prop_name, int index)
{
        if (strcmp(prop_name, "iommu-map"))
                return NULL;

        return of_parse_phandle(np, prop_name, (index * 4) + 1);
}

static const struct supplier_bindings of_supplier_bindings[] = {
        { .parse_prop = parse_clocks, },
        { .parse_prop = parse_interconnects, },
        { .parse_prop = parse_iommus, },
        { .parse_prop = parse_iommu_maps, },
        { .parse_prop = parse_mboxes, },
        { .parse_prop = parse_io_channels, },
        { .parse_prop = parse_interrupt_parent, },
        { .parse_prop = parse_dmas, },
        { .parse_prop = parse_power_domains, },
        { .parse_prop = parse_hwlocks, },
        { .parse_prop = parse_extcon, },
        { .parse_prop = parse_interrupts_extended, },
        { .parse_prop = parse_nvmem_cells, },
        { .parse_prop = parse_phys, },
        { .parse_prop = parse_wakeup_parent, },
        { .parse_prop = parse_pinctrl0, },
        { .parse_prop = parse_pinctrl1, },
        { .parse_prop = parse_pinctrl2, },
        { .parse_prop = parse_pinctrl3, },
        { .parse_prop = parse_pinctrl4, },
        { .parse_prop = parse_pinctrl5, },
        { .parse_prop = parse_pinctrl6, },
        { .parse_prop = parse_pinctrl7, },
        { .parse_prop = parse_pinctrl8, },
        { .parse_prop = parse_regulators, },
        { .parse_prop = parse_gpio, },
        { .parse_prop = parse_gpios, },
        {}
};

/**
 * of_link_property - Create device links to suppliers listed in a property
 * @dev: Consumer device
 * @con_np: The consumer device tree node which contains the property
 * @prop_name: Name of property to be parsed
 *
 * This function checks if the property @prop_name that is present in the
 * @con_np device tree node is one of the known common device tree bindings
 * that list phandles to suppliers. If @prop_name isn't one, this function
 * doesn't do anything.
 *
 * If @prop_name is one, this function attempts to create fwnode links from the
 * consumer device tree node @con_np to all the suppliers device tree nodes
 * listed in @prop_name.
 *
 * Any failed attempt to create a fwnode link will NOT result in an immediate
 * return.  of_link_property() must create links to all the available supplier
 * device tree nodes even when attempts to create a link to one or more
 * suppliers fail.
 */
static int of_link_property(struct device_node *con_np, const char *prop_name)
{
        struct device_node *phandle;
        const struct supplier_bindings *s = of_supplier_bindings;
        unsigned int i = 0;
        bool matched = false;
        int ret = 0;

        /* Do not stop at first failed link, link all available suppliers. */
        while (!matched && s->parse_prop) {
                while ((phandle = s->parse_prop(con_np, prop_name, i))) {
                        matched = true;
                        i++;
                        of_link_to_phandle(con_np, phandle);
                        of_node_put(phandle);
                }
                s++;
        }
        return ret;
}

static int of_fwnode_add_links(struct fwnode_handle *fwnode)
{
        struct property *p;
        struct device_node *con_np = to_of_node(fwnode);

        if (!con_np)
                return -EINVAL;

        for_each_property_of_node(con_np, p)
                of_link_property(con_np, p->name);

        return 0;
}

const struct fwnode_operations of_fwnode_ops = {
        .get = of_fwnode_get,
        .put = of_fwnode_put,
        .device_is_available = of_fwnode_device_is_available,
        .device_get_match_data = of_fwnode_device_get_match_data,
        .property_present = of_fwnode_property_present,
        .property_read_int_array = of_fwnode_property_read_int_array,
        .property_read_string_array = of_fwnode_property_read_string_array,
        .get_name = of_fwnode_get_name,
        .get_name_prefix = of_fwnode_get_name_prefix,
        .get_parent = of_fwnode_get_parent,
        .get_next_child_node = of_fwnode_get_next_child_node,
        .get_named_child_node = of_fwnode_get_named_child_node,
        .get_reference_args = of_fwnode_get_reference_args,
        .graph_get_next_endpoint = of_fwnode_graph_get_next_endpoint,
        .graph_get_remote_endpoint = of_fwnode_graph_get_remote_endpoint,
        .graph_get_port_parent = of_fwnode_graph_get_port_parent,
        .graph_parse_endpoint = of_fwnode_graph_parse_endpoint,
        .add_links = of_fwnode_add_links,
};
EXPORT_SYMBOL_GPL(of_fwnode_ops);