text: /*
   * 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, *ramp_delay;
  	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;
  
  	ramp_delay = of_get_property(np, "regulator-ramp-delay", NULL);
  	if (ramp_delay)
  		constraints->ramp_delay = be32_to_cpu(*ramp_delay);
  }
  
  /**
   * 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 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.
   *
   * 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;
  
  	if (!dev || !node)
  		return -EINVAL;
  
  	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);
  				return -EINVAL;
  			}
  			match->of_node = child;
  			count++;
  			break;
  		}
  	}
  
  	return count;
  }
  EXPORT_SYMBOL_GPL(of_regulator_match);
  