/*
 * helpers.c  --  Voltage/Current Regulator framework helper functions.
 *
 * Copyright 2007, 2008 Wolfson Microelectronics PLC.
 * Copyright 2008 SlimLogic Ltd.
 *
 *  This program is free software; you can redistribute  it and/or modify it
 *  under  the terms of  the GNU General  Public License as published by the
 *  Free Software Foundation;  either version 2 of the  License, or (at your
 *  option) any later version.
 *
 */

#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>

/**
 * 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);

/**
 * 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 regulator_linear_range *range;
        int ret = -EINVAL;
        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++) {
                int linear_max_uV;

                range = &rdev->desc->linear_ranges[i];
                linear_max_uV = range->min_uV +
                        (range->max_sel - range->min_sel) * range->uV_step;

                if (!(min_uV <= linear_max_uV && max_uV >= range->min_uV))
                        continue;

                if (min_uV <= range->min_uV)
                        min_uV = range->min_uV;

                /* range->uV_step == 0 means fixed voltage range */
                if (range->uV_step == 0) {
                        ret = 0;
                } else {
                        ret = DIV_ROUND_UP(min_uV - range->min_uV,
                                           range->uV_step);
                        if (ret < 0)
                                return ret;
                }

                ret += range->min_sel;

                break;
        }

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

        /* 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_range);

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

        selector -= rdev->desc->linear_min_sel;

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

/**
 * 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)
{
        const struct regulator_linear_range *range;
        int 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];

                if (!(selector >= range->min_sel &&
                      selector <= range->max_sel))
                        continue;

                selector -= range->min_sel;

                return range->min_uV + (range->uV_step * selector);
        }

        return -EINVAL;
}
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;

        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_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;
        int ret;

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

        *enable = val & rdev->desc->bypass_mask;

        return 0;
}
EXPORT_SYMBOL_GPL(regulator_get_bypass_regmap);