/*
   * Device tree integration for the pin control subsystem
   *
   * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
   *
   * This program is free software; you can redistribute it and/or modify it
   * under the terms and conditions of the GNU General Public License,
   * version 2, as published by the Free Software Foundation.
   *
   * This program is distributed in the hope it will be useful, but WITHOUT
   * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
   * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
   * more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program.  If not, see <http://www.gnu.org/licenses/>.
   */
  
  #include <linux/device.h>
  #include <linux/of.h>
  #include <linux/of_gpio.h>
  #include <linux/pinctrl/pinctrl.h>
  #include <linux/slab.h>
  
  #include "core.h"
  #include "devicetree.h"
  
  /**
   * struct pinctrl_dt_map - mapping table chunk parsed from device tree
   * @node: list node for struct pinctrl's @dt_maps field
   * @pctldev: the pin controller that allocated this struct, and will free it
   * @maps: the mapping table entries
   */
  struct pinctrl_dt_map {
  	struct list_head node;
  	struct pinctrl_dev *pctldev;
  	struct pinctrl_map *map;
  	unsigned num_maps;
  };
  
  static void dt_free_map(struct pinctrl_dev *pctldev,
  		     struct pinctrl_map *map, unsigned num_maps)
  {
  	if (pctldev) {
  		const struct pinctrl_ops *ops = pctldev->desc->pctlops;
  		ops->dt_free_map(pctldev, map, num_maps);
  	} else {
  		/* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
  		kfree(map);
  	}
  }
  
  void pinctrl_dt_free_maps(struct pinctrl *p)
  {
  	struct pinctrl_dt_map *dt_map, *n1;
  
  	list_for_each_entry_safe(dt_map, n1, &p->dt_maps, node) {
  		pinctrl_unregister_map(dt_map->map);
  		list_del(&dt_map->node);
  		dt_free_map(dt_map->pctldev, dt_map->map,
  			    dt_map->num_maps);
  		kfree(dt_map);
  	}
  
  	of_node_put(p->dev->of_node);
  }
  
  static int dt_remember_or_free_map(struct pinctrl *p, const char *statename,
  				   struct pinctrl_dev *pctldev,
  				   struct pinctrl_map *map, unsigned num_maps)
  {
  	int i;
  	struct pinctrl_dt_map *dt_map;
  
  	/* Initialize common mapping table entry fields */
  	for (i = 0; i < num_maps; i++) {
  		map[i].dev_name = dev_name(p->dev);
  		map[i].name = statename;
  		if (pctldev)
  			map[i].ctrl_dev_name = dev_name(pctldev->dev);
  	}
  
  	/* Remember the converted mapping table entries */
  	dt_map = kzalloc(sizeof(*dt_map), GFP_KERNEL);
  	if (!dt_map) {
  		dev_err(p->dev, "failed to alloc struct pinctrl_dt_map
  ");
  		dt_free_map(pctldev, map, num_maps);
  		return -ENOMEM;
  	}
  
  	dt_map->pctldev = pctldev;
  	dt_map->map = map;
  	dt_map->num_maps = num_maps;
  	list_add_tail(&dt_map->node, &p->dt_maps);
  
  	return pinctrl_register_map(map, num_maps, false, true);
  }
  
  struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
  {
  	struct pinctrl_dev *pctldev;
  
  	pctldev = get_pinctrl_dev_from_of_node(np);
  	if (!pctldev)
  		return NULL;
  
  	return pctldev;
  }
  
  static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
  				struct device_node *np_config)
  {
  	struct device_node *np_pctldev;
  	struct pinctrl_dev *pctldev;
  	const struct pinctrl_ops *ops;
  	int ret;
  	struct pinctrl_map *map;
  	unsigned num_maps;
  
  	/* Find the pin controller containing np_config */
  	np_pctldev = of_node_get(np_config);
  	for (;;) {
  		np_pctldev = of_get_next_parent(np_pctldev);
  		if (!np_pctldev || of_node_is_root(np_pctldev)) {
  			dev_info(p->dev, "could not find pctldev for node %s, deferring probe
  ",
  				np_config->full_name);
  			of_node_put(np_pctldev);
  			/* OK let's just assume this will appear later then */
  			return -EPROBE_DEFER;
  		}
  		pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
  		if (pctldev)
  			break;
  		/* Do not defer probing of hogs (circular loop) */
  		if (np_pctldev == p->dev->of_node) {
  			of_node_put(np_pctldev);
  			return -ENODEV;
  		}
  	}
  	of_node_put(np_pctldev);
  
  	/*
  	 * Call pinctrl driver to parse device tree node, and
  	 * generate mapping table entries
  	 */
  	ops = pctldev->desc->pctlops;
  	if (!ops->dt_node_to_map) {
  		dev_err(p->dev, "pctldev %s doesn't support DT
  ",
  			dev_name(pctldev->dev));
  		return -ENODEV;
  	}
  	ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
  	if (ret < 0)
  		return ret;
  
  	/* Stash the mapping table chunk away for later use */
  	return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
  }
  
  static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
  {
  	struct pinctrl_map *map;
  
  	map = kzalloc(sizeof(*map), GFP_KERNEL);
  	if (!map) {
  		dev_err(p->dev, "failed to alloc struct pinctrl_map
  ");
  		return -ENOMEM;
  	}
  
  	/* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
  	map->type = PIN_MAP_TYPE_DUMMY_STATE;
  
  	return dt_remember_or_free_map(p, statename, NULL, map, 1);
  }
  
  static int dt_gpio_assert_pinctrl(struct pinctrl *p)
  {
  	struct device_node *np = p->dev->of_node;
  	enum of_gpio_flags flags;
  	int gpio;
  	int index = 0;
  	int ret;
  
  	if (!of_find_property(np, "pinctrl-assert-gpios", NULL))
  		return 0; /* Missing the property, so nothing to be done */
  
  	for (;; index++) {
  		gpio = of_get_named_gpio_flags(np, "pinctrl-assert-gpios",
  					       index, &flags);
  		if (gpio < 0)
  			break; /* End of the phandle list */
  
  		if (!gpio_is_valid(gpio))
  			return -EINVAL;
  
  		ret = devm_gpio_request_one(p->dev, gpio, GPIOF_OUT_INIT_LOW,
  					    NULL);
  		if (ret < 0)
  			return ret;
  
  		if (flags & OF_GPIO_ACTIVE_LOW)
  			continue;
  
  		if (gpio_cansleep(gpio))
  			gpio_set_value_cansleep(gpio, 1);
  		else
  			gpio_set_value(gpio, 1);
  	}
  
  	return 0;
  }
  
  int pinctrl_dt_to_map(struct pinctrl *p)
  {
  	struct device_node *np = p->dev->of_node;
  	int state, ret;
  	char *propname;
  	struct property *prop;
  	const char *statename;
  	const __be32 *list;
  	int size, config;
  	phandle phandle;
  	struct device_node *np_config;
  
  	/* CONFIG_OF enabled, p->dev not instantiated from DT */
  	if (!np) {
  		dev_dbg(p->dev, "no of_node; not parsing pinctrl DT
  ");
  		return 0;
  	}
  
  	ret = dt_gpio_assert_pinctrl(p);
  	if (ret) {
  		dev_dbg(p->dev, "failed to assert pinctrl setting: %d
  ", ret);
  		return ret;
  	}
  
  	/* We may store pointers to property names within the node */
  	of_node_get(np);
  
  	/* For each defined state ID */
  	for (state = 0; ; state++) {
  		/* Retrieve the pinctrl-* property */
  		propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
  		prop = of_find_property(np, propname, &size);
  		kfree(propname);
  		if (!prop)
  			break;
  		list = prop->value;
  		size /= sizeof(*list);
  
  		/* Determine whether pinctrl-names property names the state */
  		ret = of_property_read_string_index(np, "pinctrl-names",
  						    state, &statename);
  		/*
  		 * If not, statename is just the integer state ID. But rather
  		 * than dynamically allocate it and have to free it later,
  		 * just point part way into the property name for the string.
  		 */
  		if (ret < 0) {
  			/* strlen("pinctrl-") == 8 */
  			statename = prop->name + 8;
  		}
  
  		/* For every referenced pin configuration node in it */
  		for (config = 0; config < size; config++) {
  			phandle = be32_to_cpup(list++);
  
  			/* Look up the pin configuration node */
  			np_config = of_find_node_by_phandle(phandle);
  			if (!np_config) {
  				dev_err(p->dev,
  					"prop %s index %i invalid phandle
  ",
  					prop->name, config);
  				ret = -EINVAL;
  				goto err;
  			}
  
  			/* Parse the node */
  			ret = dt_to_map_one_config(p, statename, np_config);
  			of_node_put(np_config);
  			if (ret < 0)
  				goto err;
  		}
  
  		/* No entries in DT? Generate a dummy state table entry */
  		if (!size) {
  			ret = dt_remember_dummy_state(p, statename);
  			if (ret < 0)
  				goto err;
  		}
  	}
  
  	return 0;
  
  err:
  	pinctrl_dt_free_maps(p);
  	return ret;
  }