drivers/pinctrl/devicetree.c

   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  */
  33 struct pinctrl_dt_map {
  34         struct list_head node;
  35         struct pinctrl_dev *pctldev;
  36         struct pinctrl_map *map;
  37         unsigned num_maps;
  38 };
  39
  40 static 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
  52 void 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
  67 static 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
  98 static 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
 109 static 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
 154 static 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
 170 int 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
 246 err:
 247         pinctrl_dt_free_maps(p);
 248         return ret;
 249 }