/*
   * 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 const char *const regulator_states[PM_SUSPEND_MAX + 1] = {
  	[PM_SUSPEND_MEM]	= "regulator-state-mem",
  	[PM_SUSPEND_MAX]	= "regulator-state-disk",
  };
  
  static void of_get_regulation_constraints(struct device_node *np,
  					struct regulator_init_data **init_data,
  					const struct regulator_desc *desc)
  {
  	const __be32 *min_uV, *max_uV;
  	struct regulation_constraints *constraints = &(*init_data)->constraints;
  	struct regulator_state *suspend_state;
  	struct device_node *suspend_np;
  	int ret, i;
  	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;
  
  	if (!of_property_read_u32(np, "regulator-input-current-limit-microamp",
  				  &pval))
  		constraints->ilim_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;
  
  	constraints->pull_down = of_property_read_bool(np, "regulator-pull-down");
  
  	if (of_property_read_bool(np, "regulator-allow-bypass"))
  		constraints->valid_ops_mask |= REGULATOR_CHANGE_BYPASS;
  
  	if (of_property_read_bool(np, "regulator-allow-set-load"))
  		constraints->valid_ops_mask |= REGULATOR_CHANGE_DRMS;
  
  	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;
  
  	constraints->soft_start = of_property_read_bool(np,
  					"regulator-soft-start");
  
  	if (!of_property_read_u32(np, "regulator-initial-mode", &pval)) {
  		if (desc && desc->of_map_mode) {
  			ret = desc->of_map_mode(pval);
  			if (ret == -EINVAL)
  				pr_err("%s: invalid mode %u
  ", np->name, pval);
  			else
  				constraints->initial_mode = ret;
  		} else {
  			pr_warn("%s: mapping for mode %d not defined
  ",
  				np->name, pval);
  		}
  	}
  
  	if (!of_property_read_u32(np, "regulator-system-load", &pval))
  		constraints->system_load = pval;
  
  	constraints->over_current_protection = of_property_read_bool(np,
  					"regulator-over-current-protection");
  
  	for (i = 0; i < ARRAY_SIZE(regulator_states); i++) {
  		switch (i) {
  		case PM_SUSPEND_MEM:
  			suspend_state = &constraints->state_mem;
  			break;
  		case PM_SUSPEND_MAX:
  			suspend_state = &constraints->state_disk;
  			break;
  		case PM_SUSPEND_ON:
  		case PM_SUSPEND_FREEZE:
  		case PM_SUSPEND_STANDBY:
  		default:
  			continue;
  		}
  
  		suspend_np = of_get_child_by_name(np, regulator_states[i]);
  		if (!suspend_np || !suspend_state)
  			continue;
  
  		if (!of_property_read_u32(suspend_np, "regulator-mode",
  					  &pval)) {
  			if (desc && desc->of_map_mode) {
  				ret = desc->of_map_mode(pval);
  				if (ret == -EINVAL)
  					pr_err("%s: invalid mode %u
  ",
  					       np->name, pval);
  				else
  					suspend_state->mode = ret;
  			} else {
  				pr_warn("%s: mapping for mode %d not defined
  ",
  					np->name, pval);
  			}
  		}
  
  		if (of_property_read_bool(suspend_np,
  					"regulator-on-in-suspend"))
  			suspend_state->enabled = true;
  		else if (of_property_read_bool(suspend_np,
  					"regulator-off-in-suspend"))
  			suspend_state->disabled = true;
  
  		if (!of_property_read_u32(suspend_np,
  					"regulator-suspend-microvolt", &pval))
  			suspend_state->uV = pval;
  
  		if (i == PM_SUSPEND_MEM)
  			constraints->initial_state = PM_SUSPEND_MEM;
  
  		of_node_put(suspend_np);
  		suspend_state = NULL;
  		suspend_np = NULL;
  	}
  }
  
  /**
   * of_get_regulator_init_data - extract regulator_init_data structure info
   * @dev: device requesting for regulator_init_data
   * @node: regulator device node
   * @desc: regulator description
   *
   * 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,
  					  const struct regulator_desc *desc)
  {
  	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, desc);
  	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,
  							   match->desc);
  			if (!match->init_data) {
  				dev_err(dev,
  					"failed to parse DT for regulator %s
  ",
  					child->name);
  				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 regulator_config *config,
  					    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'
  ",
  			desc->regulators_node);
  		return NULL;
  	}
  
  	for_each_available_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, desc);
  		if (!init_data) {
  			dev_err(dev,
  				"failed to parse DT for regulator %s
  ",
  				child->name);
  			break;
  		}
  
  		if (desc->of_parse_cb) {
  			if (desc->of_parse_cb(child, desc, config)) {
  				dev_err(dev,
  					"driver callback failed to parse DT for regulator %s
  ",
  					child->name);
  				init_data = NULL;
  				break;
  			}
  		}
  
  		of_node_get(child);
  		*node = child;
  		break;
  	}
  
  	of_node_put(search);
  
  	return init_data;
  }