// SPDX-License-Identifier: GPL-2.0-or-later
//
// helpers.c  --  Voltage/Current Regulator framework helper functions.
//
// Copyright 2007, 2008 Wolfson Microelectronics PLC.
// Copyright 2008 SlimLogic Ltd.

#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/delay.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/driver.h>
#include <linux/module.h>

#include "internal.h"

/**
 * regulator_is_enabled_regmap - standard is_enabled() for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * enable_reg and enable_mask fields in their descriptor and then use
 * this as their is_enabled operation, saving some code.
 */
int regulator_is_enabled_regmap(struct regulator_dev *rdev)
{
        unsigned int val;
        int ret;

        ret = regmap_read(rdev->regmap, rdev->desc->enable_reg, &val);
        if (ret != 0)
                return ret;

        val &= rdev->desc->enable_mask;

        if (rdev->desc->enable_is_inverted) {
                if (rdev->desc->enable_val)
                        return val != rdev->desc->enable_val;
                return val == 0;
        } else {
                if (rdev->desc->enable_val)
                        return val == rdev->desc->enable_val;
                return val != 0;
        }
}
EXPORT_SYMBOL_GPL(regulator_is_enabled_regmap);

/**
 * regulator_enable_regmap - standard enable() for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * enable_reg and enable_mask fields in their descriptor and then use
 * this as their enable() operation, saving some code.
 */
int regulator_enable_regmap(struct regulator_dev *rdev)
{
        unsigned int val;

        if (rdev->desc->enable_is_inverted) {
                val = rdev->desc->disable_val;
        } else {
                val = rdev->desc->enable_val;
                if (!val)
                        val = rdev->desc->enable_mask;
        }

        return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
                                  rdev->desc->enable_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_enable_regmap);

/**
 * regulator_disable_regmap - standard disable() for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * enable_reg and enable_mask fields in their descriptor and then use
 * this as their disable() operation, saving some code.
 */
int regulator_disable_regmap(struct regulator_dev *rdev)
{
        unsigned int val;

        if (rdev->desc->enable_is_inverted) {
                val = rdev->desc->enable_val;
                if (!val)
                        val = rdev->desc->enable_mask;
        } else {
                val = rdev->desc->disable_val;
        }

        return regmap_update_bits(rdev->regmap, rdev->desc->enable_reg,
                                  rdev->desc->enable_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_disable_regmap);

static int regulator_range_selector_to_index(struct regulator_dev *rdev,
                                             unsigned int rval)
{
        int i;

        if (!rdev->desc->linear_range_selectors)
                return -EINVAL;

        rval &= rdev->desc->vsel_range_mask;

        for (i = 0; i < rdev->desc->n_linear_ranges; i++) {
                if (rdev->desc->linear_range_selectors[i] == rval)
                        return i;
        }
        return -EINVAL;
}

/**
 * regulator_get_voltage_sel_pickable_regmap - pickable range get_voltage_sel
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O and use pickable
 * ranges can set the vsel_reg, vsel_mask, vsel_range_reg and vsel_range_mask
 * fields in their descriptor and then use this as their get_voltage_vsel
 * operation, saving some code.
 */
int regulator_get_voltage_sel_pickable_regmap(struct regulator_dev *rdev)
{
        unsigned int r_val;
        int range;
        unsigned int val;
        int ret;
        unsigned int voltages = 0;
        const struct linear_range *r = rdev->desc->linear_ranges;

        if (!r)
                return -EINVAL;

        ret = regmap_read(rdev->regmap, rdev->desc->vsel_reg, &val);
        if (ret != 0)
                return ret;

        ret = regmap_read(rdev->regmap, rdev->desc->vsel_range_reg, &r_val);
        if (ret != 0)
                return ret;

        val &= rdev->desc->vsel_mask;
        val >>= ffs(rdev->desc->vsel_mask) - 1;

        range = regulator_range_selector_to_index(rdev, r_val);
        if (range < 0)
                return -EINVAL;

        voltages = linear_range_values_in_range_array(r, range);

        return val + voltages;
}
EXPORT_SYMBOL_GPL(regulator_get_voltage_sel_pickable_regmap);

/**
 * regulator_set_voltage_sel_pickable_regmap - pickable range set_voltage_sel
 *
 * @rdev: regulator to operate on
 * @sel: Selector to set
 *
 * Regulators that use regmap for their register I/O and use pickable
 * ranges can set the vsel_reg, vsel_mask, vsel_range_reg and vsel_range_mask
 * fields in their descriptor and then use this as their set_voltage_vsel
 * operation, saving some code.
 */
int regulator_set_voltage_sel_pickable_regmap(struct regulator_dev *rdev,
                                              unsigned int sel)
{
        unsigned int range;
        int ret, i;
        unsigned int voltages_in_range = 0;

        for (i = 0; i < rdev->desc->n_linear_ranges; i++) {
                const struct linear_range *r;

                r = &rdev->desc->linear_ranges[i];
                voltages_in_range = linear_range_values_in_range(r);

                if (sel < voltages_in_range)
                        break;
                sel -= voltages_in_range;
        }

        if (i == rdev->desc->n_linear_ranges)
                return -EINVAL;

        sel <<= ffs(rdev->desc->vsel_mask) - 1;
        sel += rdev->desc->linear_ranges[i].min_sel;

        range = rdev->desc->linear_range_selectors[i];

        if (rdev->desc->vsel_reg == rdev->desc->vsel_range_reg) {
                ret = regmap_update_bits(rdev->regmap,
                                         rdev->desc->vsel_reg,
                                         rdev->desc->vsel_range_mask |
                                         rdev->desc->vsel_mask, sel | range);
        } else {
                ret = regmap_update_bits(rdev->regmap,
                                         rdev->desc->vsel_range_reg,
                                         rdev->desc->vsel_range_mask, range);
                if (ret)
                        return ret;

                ret = regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
                                  rdev->desc->vsel_mask, sel);
        }

        if (ret)
                return ret;

        if (rdev->desc->apply_bit)
                ret = regmap_update_bits(rdev->regmap, rdev->desc->apply_reg,
                                         rdev->desc->apply_bit,
                                         rdev->desc->apply_bit);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_voltage_sel_pickable_regmap);

/**
 * regulator_get_voltage_sel_regmap - standard get_voltage_sel for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * vsel_reg and vsel_mask fields in their descriptor and then use this
 * as their get_voltage_vsel operation, saving some code.
 */
int regulator_get_voltage_sel_regmap(struct regulator_dev *rdev)
{
        unsigned int val;
        int ret;

        ret = regmap_read(rdev->regmap, rdev->desc->vsel_reg, &val);
        if (ret != 0)
                return ret;

        val &= rdev->desc->vsel_mask;
        val >>= ffs(rdev->desc->vsel_mask) - 1;

        return val;
}
EXPORT_SYMBOL_GPL(regulator_get_voltage_sel_regmap);

/**
 * regulator_set_voltage_sel_regmap - standard set_voltage_sel for regmap users
 *
 * @rdev: regulator to operate on
 * @sel: Selector to set
 *
 * Regulators that use regmap for their register I/O can set the
 * vsel_reg and vsel_mask fields in their descriptor and then use this
 * as their set_voltage_vsel operation, saving some code.
 */
int regulator_set_voltage_sel_regmap(struct regulator_dev *rdev, unsigned sel)
{
        int ret;

        sel <<= ffs(rdev->desc->vsel_mask) - 1;

        ret = regmap_update_bits(rdev->regmap, rdev->desc->vsel_reg,
                                  rdev->desc->vsel_mask, sel);
        if (ret)
                return ret;

        if (rdev->desc->apply_bit)
                ret = regmap_update_bits(rdev->regmap, rdev->desc->apply_reg,
                                         rdev->desc->apply_bit,
                                         rdev->desc->apply_bit);
        return ret;
}
EXPORT_SYMBOL_GPL(regulator_set_voltage_sel_regmap);

/**
 * regulator_map_voltage_iterate - map_voltage() based on list_voltage()
 *
 * @rdev: Regulator to operate on
 * @min_uV: Lower bound for voltage
 * @max_uV: Upper bound for voltage
 *
 * Drivers implementing set_voltage_sel() and list_voltage() can use
 * this as their map_voltage() operation.  It will find a suitable
 * voltage by calling list_voltage() until it gets something in bounds
 * for the requested voltages.
 */
int regulator_map_voltage_iterate(struct regulator_dev *rdev,
                                  int min_uV, int max_uV)
{
        int best_val = INT_MAX;
        int selector = 0;
        int i, ret;

        /* Find the smallest voltage that falls within the specified
         * range.
         */
        for (i = 0; i < rdev->desc->n_voltages; i++) {
                ret = rdev->desc->ops->list_voltage(rdev, i);
                if (ret < 0)
                        continue;

                if (ret < best_val && ret >= min_uV && ret <= max_uV) {
                        best_val = ret;
                        selector = i;
                }
        }

        if (best_val != INT_MAX)
                return selector;
        else
                return -EINVAL;
}
EXPORT_SYMBOL_GPL(regulator_map_voltage_iterate);

/**
 * regulator_map_voltage_ascend - map_voltage() for ascendant voltage list
 *
 * @rdev: Regulator to operate on
 * @min_uV: Lower bound for voltage
 * @max_uV: Upper bound for voltage
 *
 * Drivers that have ascendant voltage list can use this as their
 * map_voltage() operation.
 */
int regulator_map_voltage_ascend(struct regulator_dev *rdev,
                                 int min_uV, int max_uV)
{
        int i, ret;

        for (i = 0; i < rdev->desc->n_voltages; i++) {
                ret = rdev->desc->ops->list_voltage(rdev, i);
                if (ret < 0)
                        continue;

                if (ret > max_uV)
                        break;

                if (ret >= min_uV && ret <= max_uV)
                        return i;
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(regulator_map_voltage_ascend);

/**
 * regulator_map_voltage_linear - map_voltage() for simple linear mappings
 *
 * @rdev: Regulator to operate on
 * @min_uV: Lower bound for voltage
 * @max_uV: Upper bound for voltage
 *
 * Drivers providing min_uV and uV_step in their regulator_desc can
 * use this as their map_voltage() operation.
 */
int regulator_map_voltage_linear(struct regulator_dev *rdev,
                                 int min_uV, int max_uV)
{
        int ret, voltage;

        /* Allow uV_step to be 0 for fixed voltage */
        if (rdev->desc->n_voltages == 1 && rdev->desc->uV_step == 0) {
                if (min_uV <= rdev->desc->min_uV && rdev->desc->min_uV <= max_uV)
                        return 0;
                else
                        return -EINVAL;
        }

        if (!rdev->desc->uV_step) {
                BUG_ON(!rdev->desc->uV_step);
                return -EINVAL;
        }

        if (min_uV < rdev->desc->min_uV)
                min_uV = rdev->desc->min_uV;

        ret = DIV_ROUND_UP(min_uV - rdev->desc->min_uV, rdev->desc->uV_step);
        if (ret < 0)
                return ret;

        ret += rdev->desc->linear_min_sel;

        /* Map back into a voltage to verify we're still in bounds */
        voltage = rdev->desc->ops->list_voltage(rdev, ret);
        if (voltage < min_uV || voltage > max_uV)
                return -EINVAL;

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_map_voltage_linear);

/**
 * regulator_map_voltage_linear_range - map_voltage() for multiple linear ranges
 *
 * @rdev: Regulator to operate on
 * @min_uV: Lower bound for voltage
 * @max_uV: Upper bound for voltage
 *
 * Drivers providing linear_ranges in their descriptor can use this as
 * their map_voltage() callback.
 */
int regulator_map_voltage_linear_range(struct regulator_dev *rdev,
                                       int min_uV, int max_uV)
{
        const struct linear_range *range;
        int ret = -EINVAL;
        unsigned int sel;
        bool found;
        int voltage, i;

        if (!rdev->desc->n_linear_ranges) {
                BUG_ON(!rdev->desc->n_linear_ranges);
                return -EINVAL;
        }

        for (i = 0; i < rdev->desc->n_linear_ranges; i++) {
                range = &rdev->desc->linear_ranges[i];

                ret = linear_range_get_selector_high(range, min_uV, &sel,
                                                     &found);
                if (ret)
                        continue;
                ret = sel;

                /*
                 * Map back into a voltage to verify we're still in bounds.
                 * If we are not, then continue checking rest of the ranges.
                 */
                voltage = rdev->desc->ops->list_voltage(rdev, sel);
                if (voltage >= min_uV && voltage <= max_uV)
                        break;
        }

        if (i == rdev->desc->n_linear_ranges)
                return -EINVAL;

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_map_voltage_linear_range);

/**
 * regulator_map_voltage_pickable_linear_range - map_voltage, pickable ranges
 *
 * @rdev: Regulator to operate on
 * @min_uV: Lower bound for voltage
 * @max_uV: Upper bound for voltage
 *
 * Drivers providing pickable linear_ranges in their descriptor can use
 * this as their map_voltage() callback.
 */
int regulator_map_voltage_pickable_linear_range(struct regulator_dev *rdev,
                                                int min_uV, int max_uV)
{
        const struct linear_range *range;
        int ret = -EINVAL;
        int voltage, i;
        unsigned int selector = 0;

        if (!rdev->desc->n_linear_ranges) {
                BUG_ON(!rdev->desc->n_linear_ranges);
                return -EINVAL;
        }

        for (i = 0; i < rdev->desc->n_linear_ranges; i++) {
                int linear_max_uV;
                bool found;
                unsigned int sel;

                range = &rdev->desc->linear_ranges[i];
                linear_max_uV = linear_range_get_max_value(range);

                if (!(min_uV <= linear_max_uV && max_uV >= range->min)) {
                        selector += linear_range_values_in_range(range);
                        continue;
                }

                ret = linear_range_get_selector_high(range, min_uV, &sel,
                                                     &found);
                if (ret) {
                        selector += linear_range_values_in_range(range);
                        continue;
                }

                ret = selector + sel - range->min_sel;

                voltage = rdev->desc->ops->list_voltage(rdev, ret);

                /*
                 * Map back into a voltage to verify we're still in bounds.
                 * We may have overlapping voltage ranges. Hence we don't
                 * exit but retry until we have checked all ranges.
                 */
                if (voltage < min_uV || voltage > max_uV)
                        selector += linear_range_values_in_range(range);
                else
                        break;
        }

        if (i == rdev->desc->n_linear_ranges)
                return -EINVAL;

        return ret;
}
EXPORT_SYMBOL_GPL(regulator_map_voltage_pickable_linear_range);

/**
 * regulator_desc_list_voltage_linear - List voltages with simple calculation
 *
 * @desc: Regulator desc for regulator which volatges are to be listed
 * @selector: Selector to convert into a voltage
 *
 * Regulators with a simple linear mapping between voltages and
 * selectors can set min_uV and uV_step in the regulator descriptor
 * and then use this function prior regulator registration to list
 * the voltages. This is useful when voltages need to be listed during
 * device-tree parsing.
 */
int regulator_desc_list_voltage_linear(const struct regulator_desc *desc,
                                       unsigned int selector)
{
        if (selector >= desc->n_voltages)
                return -EINVAL;

        if (selector < desc->linear_min_sel)
                return 0;

        selector -= desc->linear_min_sel;

        return desc->min_uV + (desc->uV_step * selector);
}
EXPORT_SYMBOL_GPL(regulator_desc_list_voltage_linear);

/**
 * regulator_list_voltage_linear - List voltages with simple calculation
 *
 * @rdev: Regulator device
 * @selector: Selector to convert into a voltage
 *
 * Regulators with a simple linear mapping between voltages and
 * selectors can set min_uV and uV_step in the regulator descriptor
 * and then use this function as their list_voltage() operation,
 */
int regulator_list_voltage_linear(struct regulator_dev *rdev,
                                  unsigned int selector)
{
        return regulator_desc_list_voltage_linear(rdev->desc, selector);
}
EXPORT_SYMBOL_GPL(regulator_list_voltage_linear);

/**
 * regulator_list_voltage_pickable_linear_range - pickable range list voltages
 *
 * @rdev: Regulator device
 * @selector: Selector to convert into a voltage
 *
 * list_voltage() operation, intended to be used by drivers utilizing pickable
 * ranges helpers.
 */
int regulator_list_voltage_pickable_linear_range(struct regulator_dev *rdev,
                                                 unsigned int selector)
{
        const struct linear_range *range;
        int i;
        unsigned int all_sels = 0;

        if (!rdev->desc->n_linear_ranges) {
                BUG_ON(!rdev->desc->n_linear_ranges);
                return -EINVAL;
        }

        for (i = 0; i < rdev->desc->n_linear_ranges; i++) {
                unsigned int sel_indexes;

                range = &rdev->desc->linear_ranges[i];

                sel_indexes = linear_range_values_in_range(range) - 1;

                if (all_sels + sel_indexes >= selector) {
                        selector -= all_sels;
                        /*
                         * As we see here, pickable ranges work only as
                         * long as the first selector for each pickable
                         * range is 0, and the each subsequent range for
                         * this 'pick' follow immediately at next unused
                         * selector (Eg. there is no gaps between ranges).
                         * I think this is fine but it probably should be
                         * documented. OTOH, whole pickable range stuff
                         * might benefit from some documentation
                         */
                        return range->min + (range->step * selector);
                }

                all_sels += (sel_indexes + 1);
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(regulator_list_voltage_pickable_linear_range);

/**
 * regulator_desc_list_voltage_linear_range - List voltages for linear ranges
 *
 * @desc: Regulator desc for regulator which volatges are to be listed
 * @selector: Selector to convert into a voltage
 *
 * Regulators with a series of simple linear mappings between voltages
 * and selectors who have set linear_ranges in the regulator descriptor
 * can use this function prior regulator registration to list voltages.
 * This is useful when voltages need to be listed during device-tree
 * parsing.
 */
int regulator_desc_list_voltage_linear_range(const struct regulator_desc *desc,
                                             unsigned int selector)
{
        unsigned int val;
        int ret;

        BUG_ON(!desc->n_linear_ranges);

        ret = linear_range_get_value_array(desc->linear_ranges,
                                           desc->n_linear_ranges, selector,
                                           &val);
        if (ret)
                return ret;

        return val;
}
EXPORT_SYMBOL_GPL(regulator_desc_list_voltage_linear_range);

/**
 * regulator_list_voltage_linear_range - List voltages for linear ranges
 *
 * @rdev: Regulator device
 * @selector: Selector to convert into a voltage
 *
 * Regulators with a series of simple linear mappings between voltages
 * and selectors can set linear_ranges in the regulator descriptor and
 * then use this function as their list_voltage() operation,
 */
int regulator_list_voltage_linear_range(struct regulator_dev *rdev,
                                        unsigned int selector)
{
        return regulator_desc_list_voltage_linear_range(rdev->desc, selector);
}
EXPORT_SYMBOL_GPL(regulator_list_voltage_linear_range);

/**
 * regulator_list_voltage_table - List voltages with table based mapping
 *
 * @rdev: Regulator device
 * @selector: Selector to convert into a voltage
 *
 * Regulators with table based mapping between voltages and
 * selectors can set volt_table in the regulator descriptor
 * and then use this function as their list_voltage() operation.
 */
int regulator_list_voltage_table(struct regulator_dev *rdev,
                                 unsigned int selector)
{
        if (!rdev->desc->volt_table) {
                BUG_ON(!rdev->desc->volt_table);
                return -EINVAL;
        }

        if (selector >= rdev->desc->n_voltages)
                return -EINVAL;
        if (selector < rdev->desc->linear_min_sel)
                return 0;

        return rdev->desc->volt_table[selector];
}
EXPORT_SYMBOL_GPL(regulator_list_voltage_table);

/**
 * regulator_set_bypass_regmap - Default set_bypass() using regmap
 *
 * @rdev: device to operate on.
 * @enable: state to set.
 */
int regulator_set_bypass_regmap(struct regulator_dev *rdev, bool enable)
{
        unsigned int val;

        if (enable) {
                val = rdev->desc->bypass_val_on;
                if (!val)
                        val = rdev->desc->bypass_mask;
        } else {
                val = rdev->desc->bypass_val_off;
        }

        return regmap_update_bits(rdev->regmap, rdev->desc->bypass_reg,
                                  rdev->desc->bypass_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_set_bypass_regmap);

/**
 * regulator_set_soft_start_regmap - Default set_soft_start() using regmap
 *
 * @rdev: device to operate on.
 */
int regulator_set_soft_start_regmap(struct regulator_dev *rdev)
{
        unsigned int val;

        val = rdev->desc->soft_start_val_on;
        if (!val)
                val = rdev->desc->soft_start_mask;

        return regmap_update_bits(rdev->regmap, rdev->desc->soft_start_reg,
                                  rdev->desc->soft_start_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_set_soft_start_regmap);

/**
 * regulator_set_pull_down_regmap - Default set_pull_down() using regmap
 *
 * @rdev: device to operate on.
 */
int regulator_set_pull_down_regmap(struct regulator_dev *rdev)
{
        unsigned int val;

        val = rdev->desc->pull_down_val_on;
        if (!val)
                val = rdev->desc->pull_down_mask;

        return regmap_update_bits(rdev->regmap, rdev->desc->pull_down_reg,
                                  rdev->desc->pull_down_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_set_pull_down_regmap);

/**
 * regulator_get_bypass_regmap - Default get_bypass() using regmap
 *
 * @rdev: device to operate on.
 * @enable: current state.
 */
int regulator_get_bypass_regmap(struct regulator_dev *rdev, bool *enable)
{
        unsigned int val;
        unsigned int val_on = rdev->desc->bypass_val_on;
        int ret;

        ret = regmap_read(rdev->regmap, rdev->desc->bypass_reg, &val);
        if (ret != 0)
                return ret;

        if (!val_on)
                val_on = rdev->desc->bypass_mask;

        *enable = (val & rdev->desc->bypass_mask) == val_on;

        return 0;
}
EXPORT_SYMBOL_GPL(regulator_get_bypass_regmap);

/**
 * regulator_set_active_discharge_regmap - Default set_active_discharge()
 *                                         using regmap
 *
 * @rdev: device to operate on.
 * @enable: state to set, 0 to disable and 1 to enable.
 */
int regulator_set_active_discharge_regmap(struct regulator_dev *rdev,
                                          bool enable)
{
        unsigned int val;

        if (enable)
                val = rdev->desc->active_discharge_on;
        else
                val = rdev->desc->active_discharge_off;

        return regmap_update_bits(rdev->regmap,
                                  rdev->desc->active_discharge_reg,
                                  rdev->desc->active_discharge_mask, val);
}
EXPORT_SYMBOL_GPL(regulator_set_active_discharge_regmap);

/**
 * regulator_set_current_limit_regmap - set_current_limit for regmap users
 *
 * @rdev: regulator to operate on
 * @min_uA: Lower bound for current limit
 * @max_uA: Upper bound for current limit
 *
 * Regulators that use regmap for their register I/O can set curr_table,
 * csel_reg and csel_mask fields in their descriptor and then use this
 * as their set_current_limit operation, saving some code.
 */
int regulator_set_current_limit_regmap(struct regulator_dev *rdev,
                                       int min_uA, int max_uA)
{
        unsigned int n_currents = rdev->desc->n_current_limits;
        int i, sel = -1;

        if (n_currents == 0)
                return -EINVAL;

        if (rdev->desc->curr_table) {
                const unsigned int *curr_table = rdev->desc->curr_table;
                bool ascend = curr_table[n_currents - 1] > curr_table[0];

                /* search for closest to maximum */
                if (ascend) {
                        for (i = n_currents - 1; i >= 0; i--) {
                                if (min_uA <= curr_table[i] &&
                                    curr_table[i] <= max_uA) {
                                        sel = i;
                                        break;
                                }
                        }
                } else {
                        for (i = 0; i < n_currents; i++) {
                                if (min_uA <= curr_table[i] &&
                                    curr_table[i] <= max_uA) {
                                        sel = i;
                                        break;
                                }
                        }
                }
        }

        if (sel < 0)
                return -EINVAL;

        sel <<= ffs(rdev->desc->csel_mask) - 1;

        return regmap_update_bits(rdev->regmap, rdev->desc->csel_reg,
                                  rdev->desc->csel_mask, sel);
}
EXPORT_SYMBOL_GPL(regulator_set_current_limit_regmap);

/**
 * regulator_get_current_limit_regmap - get_current_limit for regmap users
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the
 * csel_reg and csel_mask fields in their descriptor and then use this
 * as their get_current_limit operation, saving some code.
 */
int regulator_get_current_limit_regmap(struct regulator_dev *rdev)
{
        unsigned int val;
        int ret;

        ret = regmap_read(rdev->regmap, rdev->desc->csel_reg, &val);
        if (ret != 0)
                return ret;

        val &= rdev->desc->csel_mask;
        val >>= ffs(rdev->desc->csel_mask) - 1;

        if (rdev->desc->curr_table) {
                if (val >= rdev->desc->n_current_limits)
                        return -EINVAL;

                return rdev->desc->curr_table[val];
        }

        return -EINVAL;
}
EXPORT_SYMBOL_GPL(regulator_get_current_limit_regmap);

/**
 * regulator_bulk_set_supply_names - initialize the 'supply' fields in an array
 *                                   of regulator_bulk_data structs
 *
 * @consumers: array of regulator_bulk_data entries to initialize
 * @supply_names: array of supply name strings
 * @num_supplies: number of supply names to initialize
 *
 * Note: the 'consumers' array must be the size of 'num_supplies'.
 */
void regulator_bulk_set_supply_names(struct regulator_bulk_data *consumers,
                                     const char *const *supply_names,
                                     unsigned int num_supplies)
{
        unsigned int i;

        for (i = 0; i < num_supplies; i++)
                consumers[i].supply = supply_names[i];
}
EXPORT_SYMBOL_GPL(regulator_bulk_set_supply_names);

/**
 * regulator_is_equal - test whether two regulators are the same
 *
 * @reg1: first regulator to operate on
 * @reg2: second regulator to operate on
 */
bool regulator_is_equal(struct regulator *reg1, struct regulator *reg2)
{
        return reg1->rdev == reg2->rdev;
}
EXPORT_SYMBOL_GPL(regulator_is_equal);

static int find_closest_bigger(unsigned int target, const unsigned int *table,
                               unsigned int num_sel, unsigned int *sel)
{
        unsigned int s, tmp, max, maxsel = 0;
        bool found = false;

        max = table[0];

        for (s = 0; s < num_sel; s++) {
                if (table[s] > max) {
                        max = table[s];
                        maxsel = s;
                }
                if (table[s] >= target) {
                        if (!found || table[s] - target < tmp - target) {
                                tmp = table[s];
                                *sel = s;
                                found = true;
                                if (tmp == target)
                                        break;
                        }
                }
        }

        if (!found) {
                *sel = maxsel;
                return -EINVAL;
        }

        return 0;
}

/**
 * regulator_set_ramp_delay_regmap - set_ramp_delay() helper
 *
 * @rdev: regulator to operate on
 *
 * Regulators that use regmap for their register I/O can set the ramp_reg
 * and ramp_mask fields in their descriptor and then use this as their
 * set_ramp_delay operation, saving some code.
 */
int regulator_set_ramp_delay_regmap(struct regulator_dev *rdev, int ramp_delay)
{
        int ret;
        unsigned int sel;

        if (WARN_ON(!rdev->desc->n_ramp_values || !rdev->desc->ramp_delay_table))
                return -EINVAL;

        ret = find_closest_bigger(ramp_delay, rdev->desc->ramp_delay_table,
                                  rdev->desc->n_ramp_values, &sel);

        if (ret) {
                dev_warn(rdev_get_dev(rdev),
                         "Can't set ramp-delay %u, setting %u\n", ramp_delay,
                         rdev->desc->ramp_delay_table[sel]);
        }

        sel <<= ffs(rdev->desc->ramp_mask) - 1;

        return regmap_update_bits(rdev->regmap, rdev->desc->ramp_reg,
                                  rdev->desc->ramp_mask, sel);
}
EXPORT_SYMBOL_GPL(regulator_set_ramp_delay_regmap);