/*
   * 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;
  
  	if (rdev->desc->enable_is_inverted)
  		return (val & rdev->desc->enable_mask) == 0;
  	else
  		return (val & rdev->desc->enable_mask) != 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 = 0;
  	else
  		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_mask;
  	else
  		val = 0;
  
  	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 - 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_mask;
  	else
  		val = 0;
  
  	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);