/*
 * 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/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;
                if (ops->dt_free_map)
                        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) {
                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);
}

struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
{
        return get_pinctrl_dev_from_of_node(np);
}

static int dt_to_map_one_config(struct pinctrl *p,
                                struct pinctrl_dev *hog_pctldev,
                                const char *statename,
                                struct device_node *np_config)
{
        struct pinctrl_dev *pctldev = NULL;
        struct device_node *np_pctldev;
        const struct pinctrl_ops *ops;
        int ret;
        struct pinctrl_map *map;
        unsigned num_maps;
        bool allow_default = false;

        /* Find the pin controller containing np_config */
        np_pctldev = of_node_get(np_config);
        for (;;) {
                if (!allow_default)
                        allow_default = of_property_read_bool(np_pctldev,
                                                              "pinctrl-use-default");

                np_pctldev = of_get_next_parent(np_pctldev);
                if (!np_pctldev || of_node_is_root(np_pctldev)) {
                        of_node_put(np_pctldev);
                        ret = driver_deferred_probe_check_state(p->dev);
                        /* keep deferring if modules are enabled unless we've timed out */
                        if (IS_ENABLED(CONFIG_MODULES) && !allow_default && ret == -ENODEV)
                                ret = -EPROBE_DEFER;

                        return ret;
                }
                /* If we're creating a hog we can use the passed pctldev */
                if (hog_pctldev && (np_pctldev == p->dev->of_node)) {
                        pctldev = hog_pctldev;
                        break;
                }
                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\n",
                        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)
                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);
}

bool pinctrl_dt_has_hogs(struct pinctrl_dev *pctldev)
{
        struct device_node *np;
        struct property *prop;
        int size;

        np = pctldev->dev->of_node;
        if (!np)
                return false;

        prop = of_find_property(np, "pinctrl-0", &size);

        return prop ? true : false;
}

int pinctrl_dt_to_map(struct pinctrl *p, struct pinctrl_dev *pctldev)
{
        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) {
                if (of_have_populated_dt())
                        dev_dbg(p->dev,
                                "no of_node; not parsing pinctrl DT\n");
                return 0;
        }

        /* 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) {
                        if (state == 0) {
                                of_node_put(np);
                                return -ENODEV;
                        }
                        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\n",
                                        prop->name, config);
                                ret = -EINVAL;
                                goto err;
                        }

                        /* Parse the node */
                        ret = dt_to_map_one_config(p, pctldev, 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;
}

/*
 * For pinctrl binding, typically #pinctrl-cells is for the pin controller
 * device, so either parent or grandparent. See pinctrl-bindings.txt.
 */
static int pinctrl_find_cells_size(const struct device_node *np)
{
        const char *cells_name = "#pinctrl-cells";
        int cells_size, error;

        error = of_property_read_u32(np->parent, cells_name, &cells_size);
        if (error) {
                error = of_property_read_u32(np->parent->parent,
                                             cells_name, &cells_size);
                if (error)
                        return -ENOENT;
        }

        return cells_size;
}

/**
 * pinctrl_get_list_and_count - Gets the list and it's cell size and number
 * @np: pointer to device node with the property
 * @list_name: property that contains the list
 * @list: pointer for the list found
 * @cells_size: pointer for the cell size found
 * @nr_elements: pointer for the number of elements found
 *
 * Typically np is a single pinctrl entry containing the list.
 */
static int pinctrl_get_list_and_count(const struct device_node *np,
                                      const char *list_name,
                                      const __be32 **list,
                                      int *cells_size,
                                      int *nr_elements)
{
        int size;

        *cells_size = 0;
        *nr_elements = 0;

        *list = of_get_property(np, list_name, &size);
        if (!*list)
                return -ENOENT;

        *cells_size = pinctrl_find_cells_size(np);
        if (*cells_size < 0)
                return -ENOENT;

        /* First element is always the index within the pinctrl device */
        *nr_elements = (size / sizeof(**list)) / (*cells_size + 1);

        return 0;
}

/**
 * pinctrl_count_index_with_args - Count number of elements in a pinctrl entry
 * @np: pointer to device node with the property
 * @list_name: property that contains the list
 *
 * Counts the number of elements in a pinctrl array consisting of an index
 * within the controller and a number of u32 entries specified for each
 * entry. Note that device_node is always for the parent pin controller device.
 */
int pinctrl_count_index_with_args(const struct device_node *np,
                                  const char *list_name)
{
        const __be32 *list;
        int size, nr_cells, error;

        error = pinctrl_get_list_and_count(np, list_name, &list,
                                           &nr_cells, &size);
        if (error)
                return error;

        return size;
}
EXPORT_SYMBOL_GPL(pinctrl_count_index_with_args);

/**
 * pinctrl_copy_args - Populates of_phandle_args based on index
 * @np: pointer to device node with the property
 * @list: pointer to a list with the elements
 * @index: entry within the list of elements
 * @nr_cells: number of cells in the list
 * @nr_elem: number of elements for each entry in the list
 * @out_args: returned values
 *
 * Populates the of_phandle_args based on the index in the list.
 */
static int pinctrl_copy_args(const struct device_node *np,
                             const __be32 *list,
                             int index, int nr_cells, int nr_elem,
                             struct of_phandle_args *out_args)
{
        int i;

        memset(out_args, 0, sizeof(*out_args));
        out_args->np = (struct device_node *)np;
        out_args->args_count = nr_cells + 1;

        if (index >= nr_elem)
                return -EINVAL;

        list += index * (nr_cells + 1);

        for (i = 0; i < nr_cells + 1; i++)
                out_args->args[i] = be32_to_cpup(list++);

        return 0;
}

/**
 * pinctrl_parse_index_with_args - Find a node pointed by index in a list
 * @np: pointer to device node with the property
 * @list_name: property that contains the list
 * @index: index within the list
 * @out_arts: entries in the list pointed by index
 *
 * Finds the selected element in a pinctrl array consisting of an index
 * within the controller and a number of u32 entries specified for each
 * entry. Note that device_node is always for the parent pin controller device.
 */
int pinctrl_parse_index_with_args(const struct device_node *np,
                                  const char *list_name, int index,
                                  struct of_phandle_args *out_args)
{
        const __be32 *list;
        int nr_elem, nr_cells, error;

        error = pinctrl_get_list_and_count(np, list_name, &list,
                                           &nr_cells, &nr_elem);
        if (error || !nr_cells)
                return error;

        error = pinctrl_copy_args(np, list, index, nr_cells, nr_elem,
                                  out_args);
        if (error)
                return error;

        return 0;
}
EXPORT_SYMBOL_GPL(pinctrl_parse_index_with_args);