linux/drivers/pinctrl/devicetree.c
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   1/*
   2 * Device tree integration for the pin control subsystem
   3 *
   4 * Copyright (C) 2012 NVIDIA CORPORATION. All rights reserved.
   5 *
   6 * This program is free software; you can redistribute it and/or modify it
   7 * under the terms and conditions of the GNU General Public License,
   8 * version 2, as published by the Free Software Foundation.
   9 *
  10 * This program is distributed in the hope it will be useful, but WITHOUT
  11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  12 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  13 * more details.
  14 *
  15 * You should have received a copy of the GNU General Public License
  16 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  17 */
  18
  19#include <linux/device.h>
  20#include <linux/of.h>
  21#include <linux/pinctrl/pinctrl.h>
  22#include <linux/slab.h>
  23
  24#include "core.h"
  25#include "devicetree.h"
  26
  27/**
  28 * struct pinctrl_dt_map - mapping table chunk parsed from device tree
  29 * @node: list node for struct pinctrl's @dt_maps field
  30 * @pctldev: the pin controller that allocated this struct, and will free it
  31 * @maps: the mapping table entries
  32 */
  33struct pinctrl_dt_map {
  34        struct list_head node;
  35        struct pinctrl_dev *pctldev;
  36        struct pinctrl_map *map;
  37        unsigned num_maps;
  38};
  39
  40static void dt_free_map(struct pinctrl_dev *pctldev,
  41                     struct pinctrl_map *map, unsigned num_maps)
  42{
  43        if (pctldev) {
  44                const struct pinctrl_ops *ops = pctldev->desc->pctlops;
  45                ops->dt_free_map(pctldev, map, num_maps);
  46        } else {
  47                /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
  48                kfree(map);
  49        }
  50}
  51
  52void pinctrl_dt_free_maps(struct pinctrl *p)
  53{
  54        struct pinctrl_dt_map *dt_map, *n1;
  55
  56        list_for_each_entry_safe(dt_map, n1, &p->dt_maps, node) {
  57                pinctrl_unregister_map(dt_map->map);
  58                list_del(&dt_map->node);
  59                dt_free_map(dt_map->pctldev, dt_map->map,
  60                            dt_map->num_maps);
  61                kfree(dt_map);
  62        }
  63
  64        of_node_put(p->dev->of_node);
  65}
  66
  67static int dt_remember_or_free_map(struct pinctrl *p, const char *statename,
  68                                   struct pinctrl_dev *pctldev,
  69                                   struct pinctrl_map *map, unsigned num_maps)
  70{
  71        int i;
  72        struct pinctrl_dt_map *dt_map;
  73
  74        /* Initialize common mapping table entry fields */
  75        for (i = 0; i < num_maps; i++) {
  76                map[i].dev_name = dev_name(p->dev);
  77                map[i].name = statename;
  78                if (pctldev)
  79                        map[i].ctrl_dev_name = dev_name(pctldev->dev);
  80        }
  81
  82        /* Remember the converted mapping table entries */
  83        dt_map = kzalloc(sizeof(*dt_map), GFP_KERNEL);
  84        if (!dt_map) {
  85                dev_err(p->dev, "failed to alloc struct pinctrl_dt_map\n");
  86                dt_free_map(pctldev, map, num_maps);
  87                return -ENOMEM;
  88        }
  89
  90        dt_map->pctldev = pctldev;
  91        dt_map->map = map;
  92        dt_map->num_maps = num_maps;
  93        list_add_tail(&dt_map->node, &p->dt_maps);
  94
  95        return pinctrl_register_map(map, num_maps, false, true);
  96}
  97
  98struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
  99{
 100        struct pinctrl_dev *pctldev;
 101
 102        pctldev = get_pinctrl_dev_from_of_node(np);
 103        if (!pctldev)
 104                return NULL;
 105
 106        return pctldev;
 107}
 108
 109static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
 110                                struct device_node *np_config)
 111{
 112        struct device_node *np_pctldev;
 113        struct pinctrl_dev *pctldev;
 114        const struct pinctrl_ops *ops;
 115        int ret;
 116        struct pinctrl_map *map;
 117        unsigned num_maps;
 118
 119        /* Find the pin controller containing np_config */
 120        np_pctldev = of_node_get(np_config);
 121        for (;;) {
 122                np_pctldev = of_get_next_parent(np_pctldev);
 123                if (!np_pctldev || of_node_is_root(np_pctldev)) {
 124                        dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n",
 125                                np_config->full_name);
 126                        of_node_put(np_pctldev);
 127                        /* OK let's just assume this will appear later then */
 128                        return -EPROBE_DEFER;
 129                }
 130                pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
 131                if (pctldev)
 132                        break;
 133                /* Do not defer probing of hogs (circular loop) */
 134                if (np_pctldev == p->dev->of_node) {
 135                        of_node_put(np_pctldev);
 136                        return -ENODEV;
 137                }
 138        }
 139        of_node_put(np_pctldev);
 140
 141        /*
 142         * Call pinctrl driver to parse device tree node, and
 143         * generate mapping table entries
 144         */
 145        ops = pctldev->desc->pctlops;
 146        if (!ops->dt_node_to_map) {
 147                dev_err(p->dev, "pctldev %s doesn't support DT\n",
 148                        dev_name(pctldev->dev));
 149                return -ENODEV;
 150        }
 151        ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
 152        if (ret < 0)
 153                return ret;
 154
 155        /* Stash the mapping table chunk away for later use */
 156        return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
 157}
 158
 159static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
 160{
 161        struct pinctrl_map *map;
 162
 163        map = kzalloc(sizeof(*map), GFP_KERNEL);
 164        if (!map) {
 165                dev_err(p->dev, "failed to alloc struct pinctrl_map\n");
 166                return -ENOMEM;
 167        }
 168
 169        /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
 170        map->type = PIN_MAP_TYPE_DUMMY_STATE;
 171
 172        return dt_remember_or_free_map(p, statename, NULL, map, 1);
 173}
 174
 175int pinctrl_dt_to_map(struct pinctrl *p)
 176{
 177        struct device_node *np = p->dev->of_node;
 178        int state, ret;
 179        char *propname;
 180        struct property *prop;
 181        const char *statename;
 182        const __be32 *list;
 183        int size, config;
 184        phandle phandle;
 185        struct device_node *np_config;
 186
 187        /* CONFIG_OF enabled, p->dev not instantiated from DT */
 188        if (!np) {
 189                dev_dbg(p->dev, "no of_node; not parsing pinctrl DT\n");
 190                return 0;
 191        }
 192
 193        /* We may store pointers to property names within the node */
 194        of_node_get(np);
 195
 196        /* For each defined state ID */
 197        for (state = 0; ; state++) {
 198                /* Retrieve the pinctrl-* property */
 199                propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
 200                prop = of_find_property(np, propname, &size);
 201                kfree(propname);
 202                if (!prop)
 203                        break;
 204                list = prop->value;
 205                size /= sizeof(*list);
 206
 207                /* Determine whether pinctrl-names property names the state */
 208                ret = of_property_read_string_index(np, "pinctrl-names",
 209                                                    state, &statename);
 210                /*
 211                 * If not, statename is just the integer state ID. But rather
 212                 * than dynamically allocate it and have to free it later,
 213                 * just point part way into the property name for the string.
 214                 */
 215                if (ret < 0) {
 216                        /* strlen("pinctrl-") == 8 */
 217                        statename = prop->name + 8;
 218                }
 219
 220                /* For every referenced pin configuration node in it */
 221                for (config = 0; config < size; config++) {
 222                        phandle = be32_to_cpup(list++);
 223
 224                        /* Look up the pin configuration node */
 225                        np_config = of_find_node_by_phandle(phandle);
 226                        if (!np_config) {
 227                                dev_err(p->dev,
 228                                        "prop %s index %i invalid phandle\n",
 229                                        prop->name, config);
 230                                ret = -EINVAL;
 231                                goto err;
 232                        }
 233
 234                        /* Parse the node */
 235                        ret = dt_to_map_one_config(p, statename, np_config);
 236                        of_node_put(np_config);
 237                        if (ret < 0)
 238                                goto err;
 239                }
 240
 241                /* No entries in DT? Generate a dummy state table entry */
 242                if (!size) {
 243                        ret = dt_remember_dummy_state(p, statename);
 244                        if (ret < 0)
 245                                goto err;
 246                }
 247        }
 248
 249        return 0;
 250
 251err:
 252        pinctrl_dt_free_maps(p);
 253        return ret;
 254}
 255
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