/*
 * 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/driver.h>
#include <linux/regulator/of_regulator.h>

#include "internal.h"

static void of_get_regulation_constraints(struct device_node *np,
					struct regulator_init_data **init_data)
{
	const __be32 *min_uV, *max_uV;
	struct regulation_constraints *constraints = &(*init_data)->constraints;
	int ret;
	u32 pval;

	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;

	if (!of_property_read_u32(np, "regulator-microvolt-offset", &pval))
		constraints->uV_offset = pval;
	if (!of_property_read_u32(np, "regulator-min-microamp", &pval))
		constraints->min_uA = pval;
	if (!of_property_read_u32(np, "regulator-max-microamp", &pval))
		constraints->max_uA = pval;

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

	constraints->boot_on = of_property_read_bool(np, "regulator-boot-on");
	constraints->always_on = of_property_read_bool(np, "regulator-always-on");
	if (!constraints->always_on) /* status change should be possible. */
		constraints->valid_ops_mask |= REGULATOR_CHANGE_STATUS;

	if (of_property_read_bool(np, "regulator-allow-bypass"))
		constraints->valid_ops_mask |= REGULATOR_CHANGE_BYPASS;

	ret = of_property_read_u32(np, "regulator-ramp-delay", &pval);
	if (!ret) {
		if (pval)
			constraints->ramp_delay = pval;
		else
			constraints->ramp_disable = true;
	}

	ret = of_property_read_u32(np, "regulator-enable-ramp-delay", &pval);
	if (!ret)
		constraints->enable_time = pval;
}

/**
 * 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);

struct devm_of_regulator_matches {
	struct of_regulator_match *matches;
	unsigned int num_matches;
};

static void devm_of_regulator_put_matches(struct device *dev, void *res)
{
	struct devm_of_regulator_matches *devm_matches = res;
	int i;

	for (i = 0; i < devm_matches->num_matches; i++)
		of_node_put(devm_matches->matches[i].of_node);
}

/**
 * of_regulator_match - extract multiple regulator init data from device tree.
 * @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 to
 * parse regulator init data from the device tree. @node is expected to
 * contain a set of child nodes, each providing the init data for one
 * regulator. The data parsed from a child node will be matched to a regulator
 * based on either the deprecated property regulator-compatible if present,
 * or otherwise the child node's name. Note that the match table is modified
 * in place and an additional of_node reference is taken for each matched
 * regulator.
 *
 * 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;
	const char *name;
	struct device_node *child;
	struct devm_of_regulator_matches *devm_matches;

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

	devm_matches = devres_alloc(devm_of_regulator_put_matches,
				    sizeof(struct devm_of_regulator_matches),
				    GFP_KERNEL);
	if (!devm_matches)
		return -ENOMEM;

	devm_matches->matches = matches;
	devm_matches->num_matches = num_matches;

	devres_add(dev, devm_matches);

	for (i = 0; i < num_matches; i++) {
		struct of_regulator_match *match = &matches[i];
		match->init_data = NULL;
		match->of_node = NULL;
	}

	for_each_child_of_node(node, child) {
		name = of_get_property(child,
					"regulator-compatible", NULL);
		if (!name)
			name = child->name;
		for (i = 0; i < num_matches; i++) {
			struct of_regulator_match *match = &matches[i];
			if (match->of_node)
				continue;

			if (strcmp(match->name, name))
				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);
				of_node_put(child);
				return -EINVAL;
			}
			match->of_node = of_node_get(child);
			count++;
			break;
		}
	}

	return count;
}
EXPORT_SYMBOL_GPL(of_regulator_match);

struct regulator_init_data *regulator_of_get_init_data(struct device *dev,
					    const struct regulator_desc *desc,
					    struct device_node **node)
{
	struct device_node *search, *child;
	struct regulator_init_data *init_data = NULL;
	const char *name;

	if (!dev->of_node || !desc->of_match)
		return NULL;

	if (desc->regulators_node)
		search = of_get_child_by_name(dev->of_node,
					      desc->regulators_node);
	else
		search = dev->of_node;

	if (!search) {
		dev_dbg(dev, "Failed to find regulator container node '%s'\n",
			desc->regulators_node);
		return NULL;
	}

	for_each_child_of_node(search, child) {
		name = of_get_property(child, "regulator-compatible", NULL);
		if (!name)
			name = child->name;

		if (strcmp(desc->of_match, name))
			continue;

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

		of_node_get(child);
		*node = child;
		break;
	}

	of_node_put(search);

	return init_data;
}