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                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
  98static struct pinctrl_dev *find_pinctrl_by_of_node(struct device_node *np)
  99{
 100        struct pinctrl_dev *pctldev;
 101
 102        list_for_each_entry(pctldev, &pinctrldev_list, node)
 103                if (pctldev->dev->of_node == np)
 104                        return pctldev;
 105
 106        return NULL;
 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        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 = find_pinctrl_by_of_node(np_pctldev);
 131                if (pctldev)
 132                        break;
 133        }
 134        of_node_put(np_pctldev);
 135
 136        /*
 137         * Call pinctrl driver to parse device tree node, and
 138         * generate mapping table entries
 139         */
 140        ops = pctldev->desc->pctlops;
 141        if (!ops->dt_node_to_map) {
 142                dev_err(p->dev, "pctldev %s doesn't support DT\n",
 143                        dev_name(pctldev->dev));
 144                return -ENODEV;
 145        }
 146        ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
 147        if (ret < 0)
 148                return ret;
 149
 150        /* Stash the mapping table chunk away for later use */
 151        return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
 152}
 153
 154static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
 155{
 156        struct pinctrl_map *map;
 157
 158        map = kzalloc(sizeof(*map), GFP_KERNEL);
 159        if (!map) {
 160                dev_err(p->dev, "failed to alloc struct pinctrl_map\n");
 161                return -ENOMEM;
 162        }
 163
 164        /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
 165        map->type = PIN_MAP_TYPE_DUMMY_STATE;
 166
 167        return dt_remember_or_free_map(p, statename, NULL, map, 1);
 168}
 169
 170int pinctrl_dt_to_map(struct pinctrl *p)
 171{
 172        struct device_node *np = p->dev->of_node;
 173        int state, ret;
 174        char *propname;
 175        struct property *prop;
 176        const char *statename;
 177        const __be32 *list;
 178        int size, config;
 179        phandle phandle;
 180        struct device_node *np_config;
 181
 182        /* CONFIG_OF enabled, p->dev not instantiated from DT */
 183        if (!np) {
 184                dev_dbg(p->dev, "no of_node; not parsing pinctrl DT\n");
 185                return 0;
 186        }
 187
 188        /* We may store pointers to property names within the node */
 189        of_node_get(np);
 190
 191        /* For each defined state ID */
 192        for (state = 0; ; state++) {
 193                /* Retrieve the pinctrl-* property */
 194                propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
 195                prop = of_find_property(np, propname, &size);
 196                kfree(propname);
 197                if (!prop)
 198                        break;
 199                list = prop->value;
 200                size /= sizeof(*list);
 201
 202                /* Determine whether pinctrl-names property names the state */
 203                ret = of_property_read_string_index(np, "pinctrl-names",
 204                                                    state, &statename);
 205                /*
 206                 * If not, statename is just the integer state ID. But rather
 207                 * than dynamically allocate it and have to free it later,
 208                 * just point part way into the property name for the string.
 209                 */
 210                if (ret < 0) {
 211                        /* strlen("pinctrl-") == 8 */
 212                        statename = prop->name + 8;
 213                }
 214
 215                /* For every referenced pin configuration node in it */
 216                for (config = 0; config < size; config++) {
 217                        phandle = be32_to_cpup(list++);
 218
 219                        /* Look up the pin configuration node */
 220                        np_config = of_find_node_by_phandle(phandle);
 221                        if (!np_config) {
 222                                dev_err(p->dev,
 223                                        "prop %s index %i invalid phandle\n",
 224                                        prop->name, config);
 225                                ret = -EINVAL;
 226                                goto err;
 227                        }
 228
 229                        /* Parse the node */
 230                        ret = dt_to_map_one_config(p, statename, np_config);
 231                        of_node_put(np_config);
 232                        if (ret < 0)
 233                                goto err;
 234                }
 235
 236                /* No entries in DT? Generate a dummy state table entry */
 237                if (!size) {
 238                        ret = dt_remember_dummy_state(p, statename);
 239                        if (ret < 0)
 240                                goto err;
 241                }
 242        }
 243
 244        return 0;
 245
 246err:
 247        pinctrl_dt_free_maps(p);
 248        return ret;
 249}
 250
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