xref: /linux-6.12.1/drivers/regulator/helpers.c

// 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/bitops.h>
#include <linux/delay.h>
#include <linux/err.h>
#include <linux/export.h>
#include <linux/kernel.h>
#include <linux/regmap.h>
#include <linux/regulator/consumer.h>
#include <linux/regulator/driver.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_bitfield)
		return -EINVAL;

	rval &= rdev->desc->vsel_range_mask;
	rval >>= ffs(rdev->desc->vsel_range_mask) - 1;

	for (i = 0; i < rdev->desc->n_linear_ranges; i++) {
		if (rdev->desc->linear_range_selectors_bitfield[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_sel
 * 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);

static int write_separate_vsel_and_range(struct regulator_dev *rdev,
					 unsigned int sel, unsigned int range)
{
	bool range_updated;
	int ret;

	ret = regmap_update_bits_base(rdev->regmap, rdev->desc->vsel_range_reg,
				      rdev->desc->vsel_range_mask,
				      range, &range_updated, false, false);
	if (ret)
		return ret;

	/*
	 * Some PMICs treat the vsel_reg same as apply-bit. Force it to be
	 * written if the range changed, even if the old selector was same as
	 * the new one
	 */
	if (rdev->desc->range_applied_by_vsel && range_updated)
		return regmap_write_bits(rdev->regmap,
					rdev->desc->vsel_reg,
					rdev->desc->vsel_mask, sel);

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

/**
 * 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_sel
 * 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_bitfield[i];
	range <<= ffs(rdev->desc->vsel_range_mask) - 1;

	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 = write_separate_vsel_and_range(rdev, sel, range);

	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_sel 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_sel 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);

/**
 * regulator_find_closest_bigger - helper to find offset in ramp delay table
 *
 * @target: targeted ramp_delay
 * @table: table with supported ramp delays
 * @num_sel: number of entries in the table
 * @sel: Pointer to store table offset
 *
 * This is the internal helper used by regulator_set_ramp_delay_regmap to
 * map ramp delay to register value. It should only be used directly if
 * regulator_set_ramp_delay_regmap cannot handle a specific device setup
 * (e.g. because the value is split over multiple registers).
 */
int regulator_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;
}
EXPORT_SYMBOL_GPL(regulator_find_closest_bigger);

/**
 * regulator_set_ramp_delay_regmap - set_ramp_delay() helper
 *
 * @rdev: regulator to operate on
 * @ramp_delay: ramp-rate value given in units V/S (uV/uS)
 *
 * 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 = regulator_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);