/*
 * 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) {
                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\n");
                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);
}

static struct pinctrl_dev *find_pinctrl_by_of_node(struct device_node *np)
{
        struct pinctrl_dev *pctldev;

        list_for_each_entry(pctldev, &pinctrldev_list, node)
                if (pctldev->dev->of_node == np)
                        return pctldev;

        return NULL;
}

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;
        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\n",
                                np_config->full_name);
                        of_node_put(np_pctldev);
                        /* OK let's just assume this will appear later then */
                        return -EPROBE_DEFER;
                }
                pctldev = find_pinctrl_by_of_node(np_pctldev);
                if (pctldev)
                        break;
        }
        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) {
                dev_err(p->dev, "failed to alloc struct pinctrl_map\n");
                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);
}

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\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)
                        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, 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;
}