// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * OF helpers for regulator framework
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Rajendra Nayak <rnayak@ti.com>
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/driver.h>
#include <linux/regulator/of_regulator.h>

#include "internal.h"

static const char *const regulator_states[PM_SUSPEND_MAX + 1] = {
        [PM_SUSPEND_STANDBY]    = "regulator-state-standby",
        [PM_SUSPEND_MEM]        = "regulator-state-mem",
        [PM_SUSPEND_MAX]        = "regulator-state-disk",
};

static void fill_limit(int *limit, int val)
{
        if (val)
                if (val == 1)
                        *limit = REGULATOR_NOTIF_LIMIT_ENABLE;
                else
                        *limit = val;
        else
                *limit = REGULATOR_NOTIF_LIMIT_DISABLE;
}

static void of_get_regulator_prot_limits(struct device_node *np,
                                struct regulation_constraints *constraints)
{
        u32 pval;
        int i;
        static const char *const props[] = {
                "regulator-oc-%s-microamp",
                "regulator-ov-%s-microvolt",
                "regulator-temp-%s-kelvin",
                "regulator-uv-%s-microvolt",
        };
        struct notification_limit *limits[] = {
                &constraints->over_curr_limits,
                &constraints->over_voltage_limits,
                &constraints->temp_limits,
                &constraints->under_voltage_limits,
        };
        bool set[4] = {0};

        /* Protection limits: */
        for (i = 0; i < ARRAY_SIZE(props); i++) {
                char prop[255];
                bool found;
                int j;
                static const char *const lvl[] = {
                        "protection", "error", "warn"
                };
                int *l[] = {
                        &limits[i]->prot, &limits[i]->err, &limits[i]->warn,
                };

                for (j = 0; j < ARRAY_SIZE(lvl); j++) {
                        snprintf(prop, 255, props[i], lvl[j]);
                        found = !of_property_read_u32(np, prop, &pval);
                        if (found)
                                fill_limit(l[j], pval);
                        set[i] |= found;
                }
        }
        constraints->over_current_detection = set[0];
        constraints->over_voltage_detection = set[1];
        constraints->over_temp_detection = set[2];
        constraints->under_voltage_detection = set[3];
}

static int of_get_regulation_constraints(struct device *dev,
                                        struct device_node *np,
                                        struct regulator_init_data *init_data,
                                        const struct regulator_desc *desc)
{
        struct regulation_constraints *constraints = &init_data->constraints;
        struct regulator_state *suspend_state;
        struct device_node *suspend_np;
        unsigned int mode;
        int ret, i, len;
        int n_phandles;
        u32 pval;

        n_phandles = of_count_phandle_with_args(np, "regulator-coupled-with",
                                                NULL);
        n_phandles = max(n_phandles, 0);

        constraints->name = of_get_property(np, "regulator-name", NULL);

        if (!of_property_read_u32(np, "regulator-min-microvolt", &pval))
                constraints->min_uV = pval;

        if (!of_property_read_u32(np, "regulator-max-microvolt", &pval))
                constraints->max_uV = pval;

        /* Voltage change possible? */
        if (constraints->min_uV != constraints->max_uV)
                constraints->valid_ops_mask |= REGULATOR_CHANGE_VOLTAGE;

        /* Do we have a voltage range, if so try to apply it? */
        if (constraints->min_uV && constraints->max_uV)
                constraints->apply_uV = true;

        if (!of_property_read_u32(np, "regulator-microvolt-offset", &pval))
                constraints->uV_offset = pval;
        if (!of_property_read_u32(np, "regulator-min-microamp", &pval))
                constraints->min_uA = pval;
        if (!of_property_read_u32(np, "regulator-max-microamp", &pval))
                constraints->max_uA = pval;

        if (!of_property_read_u32(np, "regulator-input-current-limit-microamp",
                                  &pval))
                constraints->ilim_uA = pval;

        /* Current change possible? */
        if (constraints->min_uA != constraints->max_uA)
                constraints->valid_ops_mask |= REGULATOR_CHANGE_CURRENT;

        if (!of_property_read_u32(np, "regulator-power-budget-milliwatt", &pval))
                constraints->pw_budget_mW = pval;

        constraints->boot_on = of_property_read_bool(np, "regulator-boot-on");
        constraints->always_on = of_property_read_bool(np, "regulator-always-on");
        if (!constraints->always_on) /* status change should be possible. */
                constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;

        constraints->pull_down = of_property_read_bool(np, "regulator-pull-down");
        constraints->system_critical = of_property_read_bool(np,
                                                "system-critical-regulator");

        if (of_property_read_bool(np, "regulator-allow-bypass"))
                constraints->valid_ops_mask |= REGULATOR_CHANGE_BYPASS;

        if (of_property_read_bool(np, "regulator-allow-set-load"))
                constraints->valid_ops_mask |= REGULATOR_CHANGE_DRMS;

        ret = of_property_read_u32(np, "regulator-ramp-delay", &pval);
        if (!ret) {
                if (pval)
                        constraints->ramp_delay = pval;
                else
                        constraints->ramp_disable = true;
        }

        ret = of_property_read_u32(np, "regulator-settling-time-us", &pval);
        if (!ret)
                constraints->settling_time = pval;

        ret = of_property_read_u32(np, "regulator-settling-time-up-us", &pval);
        if (!ret)
                constraints->settling_time_up = pval;
        if (constraints->settling_time_up && constraints->settling_time) {
                pr_warn("%pOFn: ambiguous configuration for settling time, ignoring 'regulator-settling-time-up-us'\n",
                        np);
                constraints->settling_time_up = 0;
        }

        ret = of_property_read_u32(np, "regulator-settling-time-down-us",
                                   &pval);
        if (!ret)
                constraints->settling_time_down = pval;
        if (constraints->settling_time_down && constraints->settling_time) {
                pr_warn("%pOFn: ambiguous configuration for settling time, ignoring 'regulator-settling-time-down-us'\n",
                        np);
                constraints->settling_time_down = 0;
        }

        ret = of_property_read_u32(np, "regulator-enable-ramp-delay", &pval);
        if (!ret)
                constraints->enable_time = pval;

        ret = of_property_read_u32(np, "regulator-uv-less-critical-window-ms", &pval);
        if (!ret)
                constraints->uv_less_critical_window_ms = pval;
        else
                constraints->uv_less_critical_window_ms =
                                REGULATOR_DEF_UV_LESS_CRITICAL_WINDOW_MS;

        constraints->soft_start = of_property_read_bool(np,
                                        "regulator-soft-start");
        ret = of_property_read_u32(np, "regulator-active-discharge", &pval);
        if (!ret) {
                constraints->active_discharge =
                                (pval) ? REGULATOR_ACTIVE_DISCHARGE_ENABLE :
                                        REGULATOR_ACTIVE_DISCHARGE_DISABLE;
        }

        if (!of_property_read_u32(np, "regulator-initial-mode", &pval)) {
                if (desc && desc->of_map_mode) {
                        mode = desc->of_map_mode(pval);
                        if (mode == REGULATOR_MODE_INVALID)
                                pr_err("%pOFn: invalid mode %u\n", np, pval);
                        else
                                constraints->initial_mode = mode;
                } else {
                        pr_warn("%pOFn: mapping for mode %d not defined\n",
                                np, pval);
                }
        }

        len = of_property_count_elems_of_size(np, "regulator-allowed-modes",
                                                sizeof(u32));
        if (len > 0) {
                if (desc && desc->of_map_mode) {
                        for (i = 0; i < len; i++) {
                                ret = of_property_read_u32_index(np,
                                        "regulator-allowed-modes", i, &pval);
                                if (ret) {
                                        pr_err("%pOFn: couldn't read allowed modes index %d, ret=%d\n",
                                                np, i, ret);
                                        break;
                                }
                                mode = desc->of_map_mode(pval);
                                if (mode == REGULATOR_MODE_INVALID)
                                        pr_err("%pOFn: invalid regulator-allowed-modes element %u\n",
                                                np, pval);
                                else
                                        constraints->valid_modes_mask |= mode;
                        }
                        if (constraints->valid_modes_mask)
                                constraints->valid_ops_mask
                                        |= REGULATOR_CHANGE_MODE;
                } else {
                        pr_warn("%pOFn: mode mapping not defined\n", np);
                }
        }

        if (!of_property_read_u32(np, "regulator-system-load", &pval))
                constraints->system_load = pval;

        if (n_phandles) {
                constraints->max_spread = devm_kzalloc(dev,
                                sizeof(*constraints->max_spread) * n_phandles,
                                GFP_KERNEL);

                if (!constraints->max_spread)
                        return -ENOMEM;

                of_property_read_u32_array(np, "regulator-coupled-max-spread",
                                           constraints->max_spread, n_phandles);
        }

        if (!of_property_read_u32(np, "regulator-max-step-microvolt",
                                  &pval))
                constraints->max_uV_step = pval;

        constraints->over_current_protection = of_property_read_bool(np,
                                        "regulator-over-current-protection");

        of_get_regulator_prot_limits(np, constraints);

        for (i = 0; i < ARRAY_SIZE(regulator_states); i++) {
                switch (i) {
                case PM_SUSPEND_MEM:
                        suspend_state = &constraints->state_mem;
                        break;
                case PM_SUSPEND_MAX:
                        suspend_state = &constraints->state_disk;
                        break;
                case PM_SUSPEND_STANDBY:
                        suspend_state = &constraints->state_standby;
                        break;
                case PM_SUSPEND_ON:
                case PM_SUSPEND_TO_IDLE:
                default:
                        continue;
                }

                suspend_np = of_get_child_by_name(np, regulator_states[i]);
                if (!suspend_np)
                        continue;
                if (!suspend_state) {
                        of_node_put(suspend_np);
                        continue;
                }

                if (!of_property_read_u32(suspend_np, "regulator-mode",
                                          &pval)) {
                        if (desc && desc->of_map_mode) {
                                mode = desc->of_map_mode(pval);
                                if (mode == REGULATOR_MODE_INVALID)
                                        pr_err("%pOFn: invalid mode %u\n",
                                               np, pval);
                                else
                                        suspend_state->mode = mode;
                        } else {
                                pr_warn("%pOFn: mapping for mode %d not defined\n",
                                        np, pval);
                        }
                }

                if (of_property_read_bool(suspend_np,
                                        "regulator-on-in-suspend"))
                        suspend_state->enabled = ENABLE_IN_SUSPEND;
                else if (of_property_read_bool(suspend_np,
                                        "regulator-off-in-suspend"))
                        suspend_state->enabled = DISABLE_IN_SUSPEND;

                if (!of_property_read_u32(suspend_np,
                                "regulator-suspend-min-microvolt", &pval))
                        suspend_state->min_uV = pval;

                if (!of_property_read_u32(suspend_np,
                                "regulator-suspend-max-microvolt", &pval))
                        suspend_state->max_uV = pval;

                if (!of_property_read_u32(suspend_np,
                                        "regulator-suspend-microvolt", &pval))
                        suspend_state->uV = pval;
                else /* otherwise use min_uV as default suspend voltage */
                        suspend_state->uV = suspend_state->min_uV;

                if (of_property_read_bool(suspend_np,
                                        "regulator-changeable-in-suspend"))
                        suspend_state->changeable = true;

                if (i == PM_SUSPEND_MEM)
                        constraints->initial_state = PM_SUSPEND_MEM;

                of_node_put(suspend_np);
                suspend_state = NULL;
                suspend_np = NULL;
        }

        return 0;
}

/**
 * of_get_regulator_init_data - extract regulator_init_data structure info
 * @dev: device requesting for regulator_init_data
 * @node: regulator device node
 * @desc: regulator description
 *
 * Populates regulator_init_data structure by extracting data from device
 * tree node.
 *
 * Return: Pointer to a populated &struct regulator_init_data or NULL if
 *         memory allocation fails.
 */
struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
                                          struct device_node *node,
                                          const struct regulator_desc *desc)
{
        struct regulator_init_data *init_data;

        if (!node)
                return NULL;

        init_data = devm_kzalloc(dev, sizeof(*init_data), GFP_KERNEL);
        if (!init_data)
                return NULL; /* Out of memory? */

        if (of_get_regulation_constraints(dev, node, init_data, desc))
                return NULL;

        return init_data;
}
EXPORT_SYMBOL_GPL(of_get_regulator_init_data);

struct devm_of_regulator_matches {
        struct of_regulator_match *matches;
        unsigned int num_matches;
};

static void devm_of_regulator_put_matches(struct device *dev, void *res)
{
        struct devm_of_regulator_matches *devm_matches = res;
        int i;

        for (i = 0; i < devm_matches->num_matches; i++)
                of_node_put(devm_matches->matches[i].of_node);
}

/**
 * of_regulator_match - extract multiple regulator init data from device tree.
 * @dev: device requesting the data
 * @node: parent device node of the regulators
 * @matches: match table for the regulators
 * @num_matches: number of entries in match table
 *
 * This function uses a match table specified by the regulator driver to
 * parse regulator init data from the device tree. @node is expected to
 * contain a set of child nodes, each providing the init data for one
 * regulator. The data parsed from a child node will be matched to a regulator
 * based on either the deprecated property regulator-compatible if present,
 * or otherwise the child node's name. Note that the match table is modified
 * in place and an additional of_node reference is taken for each matched
 * regulator.
 *
 * Return: The number of matches found or a negative error number on failure.
 */
int of_regulator_match(struct device *dev, struct device_node *node,
                       struct of_regulator_match *matches,
                       unsigned int num_matches)
{
        unsigned int count = 0;
        unsigned int i;
        const char *name;
        struct device_node *child;
        struct devm_of_regulator_matches *devm_matches;

        if (!dev || !node)
                return -EINVAL;

        devm_matches = devres_alloc(devm_of_regulator_put_matches,
                                    sizeof(struct devm_of_regulator_matches),
                                    GFP_KERNEL);
        if (!devm_matches)
                return -ENOMEM;

        devm_matches->matches = matches;
        devm_matches->num_matches = num_matches;

        devres_add(dev, devm_matches);

        for (i = 0; i < num_matches; i++) {
                struct of_regulator_match *match = &matches[i];
                match->init_data = NULL;
                match->of_node = NULL;
        }

        for_each_child_of_node(node, child) {
                name = of_get_property(child,
                                        "regulator-compatible", NULL);
                if (!name)
                        name = child->name;
                for (i = 0; i < num_matches; i++) {
                        struct of_regulator_match *match = &matches[i];
                        if (match->of_node)
                                continue;

                        if (strcmp(match->name, name))
                                continue;

                        match->init_data =
                                of_get_regulator_init_data(dev, child,
                                                           match->desc);
                        if (!match->init_data) {
                                dev_err(dev,
                                        "failed to parse DT for regulator %pOFn\n",
                                        child);
                                of_node_put(child);
                                goto err_put;
                        }
                        match->of_node = of_node_get(child);
                        count++;
                        break;
                }
        }

        return count;

err_put:
        for (i = 0; i < num_matches; i++) {
                struct of_regulator_match *match = &matches[i];

                match->init_data = NULL;
                if (match->of_node) {
                        of_node_put(match->of_node);
                        match->of_node = NULL;
                }
        }
        return -EINVAL;
}
EXPORT_SYMBOL_GPL(of_regulator_match);

static struct
device_node *regulator_of_get_init_node(struct device *dev,
                                        const struct regulator_desc *desc)
{
        struct device_node *search, *child;
        const char *name;

        if (!dev->of_node || !desc->of_match)
                return NULL;

        if (desc->regulators_node) {
                search = of_get_child_by_name(dev->of_node,
                                              desc->regulators_node);
        } else {
                search = of_node_get(dev->of_node);

                if (!strcmp(desc->of_match, search->name))
                        return search;
        }

        if (!search) {
                dev_dbg(dev, "Failed to find regulator container node '%s'\n",
                        desc->regulators_node);
                return NULL;
        }

        for_each_available_child_of_node(search, child) {
                name = of_get_property(child, "regulator-compatible", NULL);
                if (!name) {
                        if (!desc->of_match_full_name)
                                name = child->name;
                        else
                                name = child->full_name;
                }

                if (!strcmp(desc->of_match, name)) {
                        of_node_put(search);
                        /*
                         * 'of_node_get(child)' is already performed by the
                         * for_each loop.
                         */
                        return child;
                }
        }

        of_node_put(search);

        return NULL;
}

struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
                                            const struct regulator_desc *desc,
                                            struct regulator_config *config,
                                            struct device_node **node)
{
        struct device_node *child;
        struct regulator_init_data *init_data = NULL;

        child = regulator_of_get_init_node(config->dev, desc);
        if (!child)
                return NULL;

        init_data = of_get_regulator_init_data(dev, child, desc);
        if (!init_data) {
                dev_err(dev, "failed to parse DT for regulator %pOFn\n", child);
                goto error;
        }

        if (desc->of_parse_cb) {
                int ret;

                ret = desc->of_parse_cb(child, desc, config);
                if (ret) {
                        if (ret == -EPROBE_DEFER) {
                                of_node_put(child);
                                return ERR_PTR(-EPROBE_DEFER);
                        }
                        dev_err(dev,
                                "driver callback failed to parse DT for regulator %pOFn\n",
                                child);
                        goto error;
                }
        }

        *node = child;

        return init_data;

error:
        of_node_put(child);

        return NULL;
}

/**
 * of_get_child_regulator - get a child regulator device node
 * based on supply name
 * @parent: Parent device node
 * @prop_name: Combination regulator supply name and "-supply"
 *
 * Traverse all child nodes.
 * Extract the child regulator device node corresponding to the supply name.
 *
 * Return: Pointer to the &struct device_node corresponding to the regulator
 *         if found, or %NULL if not found.
 */
static struct device_node *of_get_child_regulator(struct device_node *parent,
                                                  const char *prop_name)
{
        struct device_node *regnode = NULL;
        struct device_node *child = NULL;

        for_each_child_of_node(parent, child) {
                regnode = of_parse_phandle(child, prop_name, 0);
                if (regnode)
                        goto err_node_put;

                regnode = of_get_child_regulator(child, prop_name);
                if (regnode)
                        goto err_node_put;
        }
        return NULL;

err_node_put:
        of_node_put(child);
        return regnode;
}

/**
 * of_get_regulator - get a regulator device node based on supply name
 * @dev: Device pointer for dev_printk() messages
 * @node: Device node pointer for supply property lookup
 * @supply: regulator supply name
 *
 * Extract the regulator device node corresponding to the supply name.
 *
 * Return: Pointer to the &struct device_node corresponding to the regulator
 *         if found, or %NULL if not found.
 */
static struct device_node *of_get_regulator(struct device *dev, struct device_node *node,
                                            const char *supply)
{
        struct device_node *regnode = NULL;
        char prop_name[64]; /* 64 is max size of property name */

        dev_dbg(dev, "Looking up %s-supply from device node %pOF\n", supply, node);

        snprintf(prop_name, 64, "%s-supply", supply);
        regnode = of_parse_phandle(node, prop_name, 0);
        if (regnode)
                return regnode;

        regnode = of_get_child_regulator(dev->of_node, prop_name);
        if (regnode)
                return regnode;

        dev_dbg(dev, "Looking up %s property in node %pOF failed\n", prop_name, dev->of_node);
        return NULL;
}

static struct regulator_dev *of_find_regulator_by_node(struct device_node *np)
{
        struct device *dev;

        dev = class_find_device_by_of_node(&regulator_class, np);

        return dev ? dev_to_rdev(dev) : NULL;
}

/**
 * of_regulator_dev_lookup - lookup a regulator device with device tree only
 * @dev: Device pointer for regulator supply lookup.
 * @np: Device node pointer for regulator supply lookup.
 * @supply: Supply name or regulator ID.
 *
 * Return: Pointer to the &struct regulator_dev on success, or ERR_PTR()
 *         encoded value on error.
 *
 * If successful, returns a pointer to the &struct regulator_dev that
 * corresponds to the name @supply and with the embedded &struct device
 * refcount incremented by one. The refcount must be dropped by calling
 * put_device().
 *
 * On failure one of the following ERR_PTR() encoded values is returned:
 * * -%ENODEV if lookup fails permanently.
 * * -%EPROBE_DEFER if lookup could succeed in the future.
 */
struct regulator_dev *of_regulator_dev_lookup(struct device *dev, struct device_node *np,
                                              const char *supply)
{
        struct regulator_dev *r;
        struct device_node *node;

        node = of_get_regulator(dev, np, supply);
        if (node) {
                r = of_find_regulator_by_node(node);
                of_node_put(node);
                if (r)
                        return r;

                /*
                 * We have a node, but there is no device.
                 * assume it has not registered yet.
                 */
                return ERR_PTR(-EPROBE_DEFER);
        }

        return ERR_PTR(-ENODEV);
}

struct regulator *_of_regulator_get(struct device *dev, struct device_node *node,
                                    const char *id, enum regulator_get_type get_type)
{
        struct regulator_dev *r;
        int ret;

        ret = _regulator_get_common_check(dev, id, get_type);
        if (ret)
                return ERR_PTR(ret);

        r = of_regulator_dev_lookup(dev, node, id);
        return _regulator_get_common(r, dev, id, get_type);
}

/**
 * of_regulator_get - get regulator via device tree lookup
 * @dev: device used for dev_printk() messages
 * @node: device node for regulator "consumer"
 * @id: Supply name
 *
 * Return: pointer to struct regulator corresponding to the regulator producer,
 *         or PTR_ERR() encoded error number.
 *
 * This is intended for use by consumers that want to get a regulator
 * supply directly from a device node. This will _not_ consider supply
 * aliases. See regulator_dev_lookup().
 */
struct regulator *of_regulator_get(struct device *dev,
                                            struct device_node *node,
                                            const char *id)
{
        return _of_regulator_get(dev, node, id, NORMAL_GET);
}
EXPORT_SYMBOL_GPL(of_regulator_get);

/**
 * of_regulator_get_optional - get optional regulator via device tree lookup
 * @dev: device used for dev_printk() messages
 * @node: device node for regulator "consumer"
 * @id: Supply name
 *
 * Return: pointer to struct regulator corresponding to the regulator producer,
 *         or PTR_ERR() encoded error number.
 *
 * This is intended for use by consumers that want to get a regulator
 * supply directly from a device node, and can and want to deal with
 * absence of such supplies. This will _not_ consider supply aliases.
 * See regulator_dev_lookup().
 */
struct regulator *of_regulator_get_optional(struct device *dev,
                                            struct device_node *node,
                                            const char *id)
{
        return _of_regulator_get(dev, node, id, OPTIONAL_GET);
}
EXPORT_SYMBOL_GPL(of_regulator_get_optional);

/*
 * Returns number of regulators coupled with rdev.
 */
int of_get_n_coupled(struct regulator_dev *rdev)
{
        struct device_node *node = rdev->dev.of_node;
        int n_phandles;

        n_phandles = of_count_phandle_with_args(node,
                                                "regulator-coupled-with",
                                                NULL);

        return (n_phandles > 0) ? n_phandles : 0;
}

/* Looks for "to_find" device_node in src's "regulator-coupled-with" property */
static bool of_coupling_find_node(struct device_node *src,
                                  struct device_node *to_find,
                                  int *index)
{
        int n_phandles, i;
        bool found = false;

        n_phandles = of_count_phandle_with_args(src,
                                                "regulator-coupled-with",
                                                NULL);

        for (i = 0; i < n_phandles; i++) {
                struct device_node *tmp = of_parse_phandle(src,
                                           "regulator-coupled-with", i);

                if (!tmp)
                        break;

                /* found */
                if (tmp == to_find)
                        found = true;

                of_node_put(tmp);

                if (found) {
                        *index = i;
                        break;
                }
        }

        return found;
}

/**
 * of_check_coupling_data - Parse rdev's coupling properties and check data
 *                          consistency
 * @rdev: pointer to regulator_dev whose data is checked
 *
 * Function checks if all the following conditions are met:
 * - rdev's max_spread is greater than 0
 * - all coupled regulators have the same max_spread
 * - all coupled regulators have the same number of regulator_dev phandles
 * - all regulators are linked to each other
 *
 * Return: True if all conditions are met; false otherwise.
 */
bool of_check_coupling_data(struct regulator_dev *rdev)
{
        struct device_node *node = rdev->dev.of_node;
        int n_phandles = of_get_n_coupled(rdev);
        struct device_node *c_node;
        int index;
        int i;
        bool ret = true;

        /* iterate over rdev's phandles */
        for (i = 0; i < n_phandles; i++) {
                int max_spread = rdev->constraints->max_spread[i];
                int c_max_spread, c_n_phandles;

                if (max_spread <= 0) {
                        dev_err(&rdev->dev, "max_spread value invalid\n");
                        return false;
                }

                c_node = of_parse_phandle(node,
                                          "regulator-coupled-with", i);

                if (!c_node)
                        ret = false;

                c_n_phandles = of_count_phandle_with_args(c_node,
                                                          "regulator-coupled-with",
                                                          NULL);

                if (c_n_phandles != n_phandles) {
                        dev_err(&rdev->dev, "number of coupled reg phandles mismatch\n");
                        ret = false;
                        goto clean;
                }

                if (!of_coupling_find_node(c_node, node, &index)) {
                        dev_err(&rdev->dev, "missing 2-way linking for coupled regulators\n");
                        ret = false;
                        goto clean;
                }

                if (of_property_read_u32_index(c_node, "regulator-coupled-max-spread",
                                               index, &c_max_spread)) {
                        ret = false;
                        goto clean;
                }

                if (c_max_spread != max_spread) {
                        dev_err(&rdev->dev,
                                "coupled regulators max_spread mismatch\n");
                        ret = false;
                        goto clean;
                }

clean:
                of_node_put(c_node);
                if (!ret)
                        break;
        }

        return ret;
}

/**
 * of_parse_coupled_regulator() - Get regulator_dev pointer from rdev's property
 * @rdev: Pointer to regulator_dev, whose DTS is used as a source to parse
 *        "regulator-coupled-with" property
 * @index: Index in phandles array
 *
 * Return: Pointer to the &struct regulator_dev parsed from DTS, or %NULL if
 *         it has not yet been registered.
 */
struct regulator_dev *of_parse_coupled_regulator(struct regulator_dev *rdev,
                                                 int index)
{
        struct device_node *node = rdev->dev.of_node;
        struct device_node *c_node;
        struct regulator_dev *c_rdev;

        c_node = of_parse_phandle(node, "regulator-coupled-with", index);
        if (!c_node)
                return NULL;

        c_rdev = of_find_regulator_by_node(c_node);

        of_node_put(c_node);

        return c_rdev;
}

/*
 * Check if name is a supply name according to the '*-supply' pattern
 * return 0 if false
 * return length of supply name without the -supply
 */
static int is_supply_name(const char *name)
{
        int strs, i;

        strs = strlen(name);
        /* string need to be at minimum len(x-supply) */
        if (strs < 8)
                return 0;
        for (i = strs - 6; i > 0; i--) {
                /* find first '-' and check if right part is supply */
                if (name[i] != '-')
                        continue;
                if (strcmp(name + i + 1, "supply") != 0)
                        return 0;
                return i;
        }
        return 0;
}

/**
 * of_regulator_bulk_get_all - get multiple regulator consumers
 *
 * @dev:        Device to supply
 * @np:         device node to search for consumers
 * @consumers:  Configuration of consumers; clients are stored here.
 *
 * This helper function allows drivers to get several regulator
 * consumers in one operation.  If any of the regulators cannot be
 * acquired then any regulators that were allocated will be freed
 * before returning to the caller, and @consumers will not be
 * changed.
 *
 * Return: Number of regulators on success, or a negative error number
 *         on failure.
 */
int of_regulator_bulk_get_all(struct device *dev, struct device_node *np,
                              struct regulator_bulk_data **consumers)
{
        int num_consumers = 0;
        struct regulator *tmp;
        struct regulator_bulk_data *_consumers = NULL;
        struct property *prop;
        int i, n = 0, ret;
        char name[64];

        /*
         * first pass: get numbers of xxx-supply
         * second pass: fill consumers
         */
restart:
        for_each_property_of_node(np, prop) {
                i = is_supply_name(prop->name);
                if (i == 0)
                        continue;
                if (!_consumers) {
                        num_consumers++;
                        continue;
                } else {
                        memcpy(name, prop->name, i);
                        name[i] = '\0';
                        tmp = regulator_get(dev, name);
                        if (IS_ERR(tmp)) {
                                ret = PTR_ERR(tmp);
                                goto error;
                        }
                        _consumers[n].consumer = tmp;
                        n++;
                        continue;
                }
        }
        if (_consumers) {
                *consumers = _consumers;
                return num_consumers;
        }
        if (num_consumers == 0)
                return 0;
        _consumers = kmalloc_objs(struct regulator_bulk_data, num_consumers);
        if (!_consumers)
                return -ENOMEM;
        goto restart;

error:
        while (--n >= 0)
                regulator_put(_consumers[n].consumer);
        kfree(_consumers);
        return ret;
}
EXPORT_SYMBOL_GPL(of_regulator_bulk_get_all);