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                 const struct pinctrl_ops *ops = pctldev->desc->pctlops;
  45                 if (ops->dt_free_map)
  46                         ops->dt_free_map(pctldev, map, num_maps);
  47         } else {
  48                 /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
  49                 kfree(map);
  50         }
  51 }
  52
  53 void pinctrl_dt_free_maps(struct pinctrl *p)
  54 {
  55         struct pinctrl_dt_map *dt_map, *n1;
  56
  57         list_for_each_entry_safe(dt_map, n1, &p->dt_maps, node) {
  58                 pinctrl_unregister_map(dt_map->map);
  59                 list_del(&dt_map->node);
  60                 dt_free_map(dt_map->pctldev, dt_map->map,
  61                             dt_map->num_maps);
  62                 kfree(dt_map);
  63         }
  64
  65         of_node_put(p->dev->of_node);
  66 }
  67
  68 static int dt_remember_or_free_map(struct pinctrl *p, const char *statename,
  69                                    struct pinctrl_dev *pctldev,
  70                                    struct pinctrl_map *map, unsigned num_maps)
  71 {
  72         int i;
  73         struct pinctrl_dt_map *dt_map;
  74
  75         /* Initialize common mapping table entry fields */
  76         for (i = 0; i < num_maps; i++) {
  77                 map[i].dev_name = dev_name(p->dev);
  78                 map[i].name = statename;
  79                 if (pctldev)
  80                         map[i].ctrl_dev_name = dev_name(pctldev->dev);
  81         }
  82
  83         /* Remember the converted mapping table entries */
  84         dt_map = kzalloc(sizeof(*dt_map), GFP_KERNEL);
  85         if (!dt_map) {
  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);
  96 }
  97
  98 struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
  99 {
 100         return get_pinctrl_dev_from_of_node(np);
 101 }
 102
 103 static int dt_to_map_one_config(struct pinctrl *p,
 104                                 struct pinctrl_dev *hog_pctldev,
 105                                 const char *statename,
 106                                 struct device_node *np_config)
 107 {
 108         struct pinctrl_dev *pctldev = NULL;
 109         struct device_node *np_pctldev;
 110         const struct pinctrl_ops *ops;
 111         int ret;
 112         struct pinctrl_map *map;
 113         unsigned num_maps;
 114
 115         /* Find the pin controller containing np_config */
 116         np_pctldev = of_node_get(np_config);
 117         for (;;) {
 118                 np_pctldev = of_get_next_parent(np_pctldev);
 119                 if (!np_pctldev || of_node_is_root(np_pctldev)) {
 120                         dev_info(p->dev, "could not find pctldev for node %pOF, deferring probe\n",
 121                                 np_config);
 122                         of_node_put(np_pctldev);
 123                         /* OK let's just assume this will appear later then */
 124                         return -EPROBE_DEFER;
 125                 }
 126                 /* If we're creating a hog we can use the passed pctldev */
 127                 if (hog_pctldev && (np_pctldev == p->dev->of_node)) {
 128                         pctldev = hog_pctldev;
 129                         break;
 130                 }
 131                 pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
 132                 if (pctldev)
 133                         break;
 134                 /* Do not defer probing of hogs (circular loop) */
 135                 if (np_pctldev == p->dev->of_node) {
 136                         of_node_put(np_pctldev);
 137                         return -ENODEV;
 138                 }
 139         }
 140         of_node_put(np_pctldev);
 141
 142         /*
 143          * Call pinctrl driver to parse device tree node, and
 144          * generate mapping table entries
 145          */
 146         ops = pctldev->desc->pctlops;
 147         if (!ops->dt_node_to_map) {
 148                 dev_err(p->dev, "pctldev %s doesn't support DT\n",
 149                         dev_name(pctldev->dev));
 150                 return -ENODEV;
 151         }
 152         ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
 153         if (ret < 0)
 154                 return ret;
 155
 156         /* Stash the mapping table chunk away for later use */
 157         return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
 158 }
 159
 160 static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
 161 {
 162         struct pinctrl_map *map;
 163
 164         map = kzalloc(sizeof(*map), GFP_KERNEL);
 165         if (!map)
 166                 return -ENOMEM;
 167
 168         /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
 169         map->type = PIN_MAP_TYPE_DUMMY_STATE;
 170
 171         return dt_remember_or_free_map(p, statename, NULL, map, 1);
 172 }
 173
 174 bool pinctrl_dt_has_hogs(struct pinctrl_dev *pctldev)
 175 {
 176         struct device_node *np;
 177         struct property *prop;
 178         int size;
 179
 180         np = pctldev->dev->of_node;
 181         if (!np)
 182                 return false;
 183
 184         prop = of_find_property(np, "pinctrl-0", &size);
 185
 186         return prop ? true : false;
 187 }
 188
 189 int pinctrl_dt_to_map(struct pinctrl *p, struct pinctrl_dev *pctldev)
 190 {
 191         struct device_node *np = p->dev->of_node;
 192         int state, ret;
 193         char *propname;
 194         struct property *prop;
 195         const char *statename;
 196         const __be32 *list;
 197         int size, config;
 198         phandle phandle;
 199         struct device_node *np_config;
 200
 201         /* CONFIG_OF enabled, p->dev not instantiated from DT */
 202         if (!np) {
 203                 if (of_have_populated_dt())
 204                         dev_dbg(p->dev,
 205                                 "no of_node; not parsing pinctrl DT\n");
 206                 return 0;
 207         }
 208
 209         /* We may store pointers to property names within the node */
 210         of_node_get(np);
 211
 212         /* For each defined state ID */
 213         for (state = 0; ; state++) {
 214                 /* Retrieve the pinctrl-* property */
 215                 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
 216                 prop = of_find_property(np, propname, &size);
 217                 kfree(propname);
 218                 if (!prop) {
 219                         if (state == 0) {
 220                                 of_node_put(np);
 221                                 return -ENODEV;
 222                         }
 223                         break;
 224                 }
 225                 list = prop->value;
 226                 size /= sizeof(*list);
 227
 228                 /* Determine whether pinctrl-names property names the state */
 229                 ret = of_property_read_string_index(np, "pinctrl-names",
 230                                                     state, &statename);
 231                 /*
 232                  * If not, statename is just the integer state ID. But rather
 233                  * than dynamically allocate it and have to free it later,
 234                  * just point part way into the property name for the string.
 235                  */
 236                 if (ret < 0) {
 237                         /* strlen("pinctrl-") == 8 */
 238                         statename = prop->name + 8;
 239                 }
 240
 241                 /* For every referenced pin configuration node in it */
 242                 for (config = 0; config < size; config++) {
 243                         phandle = be32_to_cpup(list++);
 244
 245                         /* Look up the pin configuration node */
 246                         np_config = of_find_node_by_phandle(phandle);
 247                         if (!np_config) {
 248                                 dev_err(p->dev,
 249                                         "prop %s index %i invalid phandle\n",
 250                                         prop->name, config);
 251                                 ret = -EINVAL;
 252                                 goto err;
 253                         }
 254
 255                         /* Parse the node */
 256                         ret = dt_to_map_one_config(p, pctldev, statename,
 257                                                    np_config);
 258                         of_node_put(np_config);
 259                         if (ret < 0)
 260                                 goto err;
 261                 }
 262
 263                 /* No entries in DT? Generate a dummy state table entry */
 264                 if (!size) {
 265                         ret = dt_remember_dummy_state(p, statename);
 266                         if (ret < 0)
 267                                 goto err;
 268                 }
 269         }
 270
 271         return 0;
 272
 273 err:
 274         pinctrl_dt_free_maps(p);
 275         return ret;
 276 }
 277
 278 /*
 279  * For pinctrl binding, typically #pinctrl-cells is for the pin controller
 280  * device, so either parent or grandparent. See pinctrl-bindings.txt.
 281  */
 282 static int pinctrl_find_cells_size(const struct device_node *np)
 283 {
 284         const char *cells_name = "#pinctrl-cells";
 285         int cells_size, error;
 286
 287         error = of_property_read_u32(np->parent, cells_name, &cells_size);
 288         if (error) {
 289                 error = of_property_read_u32(np->parent->parent,
 290                                              cells_name, &cells_size);
 291                 if (error)
 292                         return -ENOENT;
 293         }
 294
 295         return cells_size;
 296 }
 297
 298 /**
 299  * pinctrl_get_list_and_count - Gets the list and it's cell size and number
 300  * @np: pointer to device node with the property
 301  * @list_name: property that contains the list
 302  * @list: pointer for the list found
 303  * @cells_size: pointer for the cell size found
 304  * @nr_elements: pointer for the number of elements found
 305  *
 306  * Typically np is a single pinctrl entry containing the list.
 307  */
 308 static int pinctrl_get_list_and_count(const struct device_node *np,
 309                                       const char *list_name,
 310                                       const __be32 **list,
 311                                       int *cells_size,
 312                                       int *nr_elements)
 313 {
 314         int size;
 315
 316         *cells_size = 0;
 317         *nr_elements = 0;
 318
 319         *list = of_get_property(np, list_name, &size);
 320         if (!*list)
 321                 return -ENOENT;
 322
 323         *cells_size = pinctrl_find_cells_size(np);
 324         if (*cells_size < 0)
 325                 return -ENOENT;
 326
 327         /* First element is always the index within the pinctrl device */
 328         *nr_elements = (size / sizeof(**list)) / (*cells_size + 1);
 329
 330         return 0;
 331 }
 332
 333 /**
 334  * pinctrl_count_index_with_args - Count number of elements in a pinctrl entry
 335  * @np: pointer to device node with the property
 336  * @list_name: property that contains the list
 337  *
 338  * Counts the number of elements in a pinctrl array consisting of an index
 339  * within the controller and a number of u32 entries specified for each
 340  * entry. Note that device_node is always for the parent pin controller device.
 341  */
 342 int pinctrl_count_index_with_args(const struct device_node *np,
 343                                   const char *list_name)
 344 {
 345         const __be32 *list;
 346         int size, nr_cells, error;
 347
 348         error = pinctrl_get_list_and_count(np, list_name, &list,
 349                                            &nr_cells, &size);
 350         if (error)
 351                 return error;
 352
 353         return size;
 354 }
 355 EXPORT_SYMBOL_GPL(pinctrl_count_index_with_args);
 356
 357 /**
 358  * pinctrl_copy_args - Populates of_phandle_args based on index
 359  * @np: pointer to device node with the property
 360  * @list: pointer to a list with the elements
 361  * @index: entry within the list of elements
 362  * @nr_cells: number of cells in the list
 363  * @nr_elem: number of elements for each entry in the list
 364  * @out_args: returned values
 365  *
 366  * Populates the of_phandle_args based on the index in the list.
 367  */
 368 static int pinctrl_copy_args(const struct device_node *np,
 369                              const __be32 *list,
 370                              int index, int nr_cells, int nr_elem,
 371                              struct of_phandle_args *out_args)
 372 {
 373         int i;
 374
 375         memset(out_args, 0, sizeof(*out_args));
 376         out_args->np = (struct device_node *)np;
 377         out_args->args_count = nr_cells + 1;
 378
 379         if (index >= nr_elem)
 380                 return -EINVAL;
 381
 382         list += index * (nr_cells + 1);
 383
 384         for (i = 0; i < nr_cells + 1; i++)
 385                 out_args->args[i] = be32_to_cpup(list++);
 386
 387         return 0;
 388 }
 389
 390 /**
 391  * pinctrl_parse_index_with_args - Find a node pointed by index in a list
 392  * @np: pointer to device node with the property
 393  * @list_name: property that contains the list
 394  * @index: index within the list
 395  * @out_arts: entries in the list pointed by index
 396  *
 397  * Finds the selected element in a pinctrl array consisting of an index
 398  * within the controller and a number of u32 entries specified for each
 399  * entry. Note that device_node is always for the parent pin controller device.
 400  */
 401 int pinctrl_parse_index_with_args(const struct device_node *np,
 402                                   const char *list_name, int index,
 403                                   struct of_phandle_args *out_args)
 404 {
 405         const __be32 *list;
 406         int nr_elem, nr_cells, error;
 407
 408         error = pinctrl_get_list_and_count(np, list_name, &list,
 409                                            &nr_cells, &nr_elem);
 410         if (error || !nr_cells)
 411                 return error;
 412
 413         error = pinctrl_copy_args(np, list, index, nr_cells, nr_elem,
 414                                   out_args);
 415         if (error)
 416                 return error;
 417
 418         return 0;
 419 }
 420 EXPORT_SYMBOL_GPL(pinctrl_parse_index_with_args);