/*
 * OF helpers for regulator framework
 *
 * Copyright (C) 2011 Texas Instruments, Inc.
 * Rajendra Nayak <rnayak@ti.com>
 *
 * 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/module.h>
#include <linux/slab.h>
#include <linux/of.h>
#include <linux/regulator/machine.h>
#include <linux/regulator/of_regulator.h>

static void of_get_regulation_constraints(struct device_node *np,
					struct regulator_init_data **init_data)
{
	const __be32 *min_uV, *max_uV, *uV_offset;
	const __be32 *min_uA, *max_uA;
	struct regulation_constraints *constraints = &(*init_data)->constraints;

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

	min_uV = of_get_property(np, "regulator-min-microvolt", NULL);
	if (min_uV)
		constraints->min_uV = be32_to_cpu(*min_uV);
	max_uV = of_get_property(np, "regulator-max-microvolt", NULL);
	if (max_uV)
		constraints->max_uV = be32_to_cpu(*max_uV);

	/* Voltage change possible? */
	if (constraints->min_uV != constraints->max_uV)
		constraints->valid_ops_mask |= REGULATOR_CHANGE_VOLTAGE;
	/* Only one voltage?  Then make sure it's set. */
	if (min_uV && max_uV && constraints->min_uV == constraints->max_uV)
		constraints->apply_uV = true;

	uV_offset = of_get_property(np, "regulator-microvolt-offset", NULL);
	if (uV_offset)
		constraints->uV_offset = be32_to_cpu(*uV_offset);
	min_uA = of_get_property(np, "regulator-min-microamp", NULL);
	if (min_uA)
		constraints->min_uA = be32_to_cpu(*min_uA);
	max_uA = of_get_property(np, "regulator-max-microamp", NULL);
	if (max_uA)
		constraints->max_uA = be32_to_cpu(*max_uA);

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

	if (of_find_property(np, "regulator-boot-on", NULL))
		constraints->boot_on = true;

	if (of_find_property(np, "regulator-always-on", NULL))
		constraints->always_on = true;
	else /* status change should be possible if not always on. */
		constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;
}

/**
 * of_get_regulator_init_data - extract regulator_init_data structure info
 * @dev: device requesting for regulator_init_data
 *
 * Populates regulator_init_data structure by extracting data from device
 * tree node, returns a pointer to the populated struture or NULL if memory
 * alloc fails.
 */
struct regulator_init_data *of_get_regulator_init_data(struct device *dev,
						struct device_node *node)
{
	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? */

	of_get_regulation_constraints(node, &init_data);
	return init_data;
}
EXPORT_SYMBOL_GPL(of_get_regulator_init_data);

/**
 * of_regulator_match - extract regulator init data
 * @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 and
 * looks up the corresponding init data in the device tree. Note that the
 * match table is modified in place.
 *
 * Returns the number of matches found or a negative error code 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;

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

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

		child = of_find_node_by_name(node, match->name);
		if (!child)
			continue;

		match->init_data = of_get_regulator_init_data(dev, child);
		if (!match->init_data) {
			dev_err(dev, "failed to parse DT for regulator %s\n",
				child->name);
			return -EINVAL;
		}

		match->of_node = child;
		count++;
	}

	return count;
}
EXPORT_SYMBOL_GPL(of_regulator_match);