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                 dev_err(p->dev, "failed to alloc struct pinctrl_dt_map\n");
  87                 dt_free_map(pctldev, map, num_maps);
  88                 return -ENOMEM;
  89         }
  90
  91         dt_map->pctldev = pctldev;
  92         dt_map->map = map;
  93         dt_map->num_maps = num_maps;
  94         list_add_tail(&dt_map->node, &p->dt_maps);
  95
  96         return pinctrl_register_map(map, num_maps, false);
  97 }
  98
  99 struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
 100 {
 101         return get_pinctrl_dev_from_of_node(np);
 102 }
 103
 104 static int dt_to_map_one_config(struct pinctrl *p,
 105                                 struct pinctrl_dev *pctldev,
 106                                 const char *statename,
 107                                 struct device_node *np_config)
 108 {
 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 %s, deferring probe\n",
 121                                 np_config->full_name);
 122                         of_node_put(np_pctldev);
 123                         /* OK let's just assume this will appear later then */
 124                         return -EPROBE_DEFER;
 125                 }
 126                 if (!pctldev)
 127                         pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
 128                 if (pctldev)
 129                         break;
 130                 /* Do not defer probing of hogs (circular loop) */
 131                 if (np_pctldev == p->dev->of_node) {
 132                         of_node_put(np_pctldev);
 133                         return -ENODEV;
 134                 }
 135         }
 136         of_node_put(np_pctldev);
 137
 138         /*
 139          * Call pinctrl driver to parse device tree node, and
 140          * generate mapping table entries
 141          */
 142         ops = pctldev->desc->pctlops;
 143         if (!ops->dt_node_to_map) {
 144                 dev_err(p->dev, "pctldev %s doesn't support DT\n",
 145                         dev_name(pctldev->dev));
 146                 return -ENODEV;
 147         }
 148         ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
 149         if (ret < 0)
 150                 return ret;
 151
 152         /* Stash the mapping table chunk away for later use */
 153         return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
 154 }
 155
 156 static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
 157 {
 158         struct pinctrl_map *map;
 159
 160         map = kzalloc(sizeof(*map), GFP_KERNEL);
 161         if (!map) {
 162                 dev_err(p->dev, "failed to alloc struct pinctrl_map\n");
 163                 return -ENOMEM;
 164         }
 165
 166         /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
 167         map->type = PIN_MAP_TYPE_DUMMY_STATE;
 168
 169         return dt_remember_or_free_map(p, statename, NULL, map, 1);
 170 }
 171
 172 bool pinctrl_dt_has_hogs(struct pinctrl_dev *pctldev)
 173 {
 174         struct device_node *np;
 175         struct property *prop;
 176         int size;
 177
 178         np = pctldev->dev->of_node;
 179         if (!np)
 180                 return false;
 181
 182         prop = of_find_property(np, "pinctrl-0", &size);
 183
 184         return prop ? true : false;
 185 }
 186
 187 int pinctrl_dt_to_map(struct pinctrl *p, struct pinctrl_dev *pctldev)
 188 {
 189         struct device_node *np = p->dev->of_node;
 190         int state, ret;
 191         char *propname;
 192         struct property *prop;
 193         const char *statename;
 194         const __be32 *list;
 195         int size, config;
 196         phandle phandle;
 197         struct device_node *np_config;
 198
 199         /* CONFIG_OF enabled, p->dev not instantiated from DT */
 200         if (!np) {
 201                 if (of_have_populated_dt())
 202                         dev_dbg(p->dev,
 203                                 "no of_node; not parsing pinctrl DT\n");
 204                 return 0;
 205         }
 206
 207         /* We may store pointers to property names within the node */
 208         of_node_get(np);
 209
 210         /* For each defined state ID */
 211         for (state = 0; ; state++) {
 212                 /* Retrieve the pinctrl-* property */
 213                 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
 214                 prop = of_find_property(np, propname, &size);
 215                 kfree(propname);
 216                 if (!prop) {
 217                         if (state == 0) {
 218                                 of_node_put(np);
 219                                 return -ENODEV;
 220                         }
 221                         break;
 222                 }
 223                 list = prop->value;
 224                 size /= sizeof(*list);
 225
 226                 /* Determine whether pinctrl-names property names the state */
 227                 ret = of_property_read_string_index(np, "pinctrl-names",
 228                                                     state, &statename);
 229                 /*
 230                  * If not, statename is just the integer state ID. But rather
 231                  * than dynamically allocate it and have to free it later,
 232                  * just point part way into the property name for the string.
 233                  */
 234                 if (ret < 0) {
 235                         /* strlen("pinctrl-") == 8 */
 236                         statename = prop->name + 8;
 237                 }
 238
 239                 /* For every referenced pin configuration node in it */
 240                 for (config = 0; config < size; config++) {
 241                         phandle = be32_to_cpup(list++);
 242
 243                         /* Look up the pin configuration node */
 244                         np_config = of_find_node_by_phandle(phandle);
 245                         if (!np_config) {
 246                                 dev_err(p->dev,
 247                                         "prop %s index %i invalid phandle\n",
 248                                         prop->name, config);
 249                                 ret = -EINVAL;
 250                                 goto err;
 251                         }
 252
 253                         /* Parse the node */
 254                         ret = dt_to_map_one_config(p, pctldev, statename,
 255                                                    np_config);
 256                         of_node_put(np_config);
 257                         if (ret < 0)
 258                                 goto err;
 259                 }
 260
 261                 /* No entries in DT? Generate a dummy state table entry */
 262                 if (!size) {
 263                         ret = dt_remember_dummy_state(p, statename);
 264                         if (ret < 0)
 265                                 goto err;
 266                 }
 267         }
 268
 269         return 0;
 270
 271 err:
 272         pinctrl_dt_free_maps(p);
 273         return ret;
 274 }
 275
 276 /*
 277  * For pinctrl binding, typically #pinctrl-cells is for the pin controller
 278  * device, so either parent or grandparent. See pinctrl-bindings.txt.
 279  */
 280 static int pinctrl_find_cells_size(const struct device_node *np)
 281 {
 282         const char *cells_name = "#pinctrl-cells";
 283         int cells_size, error;
 284
 285         error = of_property_read_u32(np->parent, cells_name, &cells_size);
 286         if (error) {
 287                 error = of_property_read_u32(np->parent->parent,
 288                                              cells_name, &cells_size);
 289                 if (error)
 290                         return -ENOENT;
 291         }
 292
 293         return cells_size;
 294 }
 295
 296 /**
 297  * pinctrl_get_list_and_count - Gets the list and it's cell size and number
 298  * @np: pointer to device node with the property
 299  * @list_name: property that contains the list
 300  * @list: pointer for the list found
 301  * @cells_size: pointer for the cell size found
 302  * @nr_elements: pointer for the number of elements found
 303  *
 304  * Typically np is a single pinctrl entry containing the list.
 305  */
 306 static int pinctrl_get_list_and_count(const struct device_node *np,
 307                                       const char *list_name,
 308                                       const __be32 **list,
 309                                       int *cells_size,
 310                                       int *nr_elements)
 311 {
 312         int size;
 313
 314         *cells_size = 0;
 315         *nr_elements = 0;
 316
 317         *list = of_get_property(np, list_name, &size);
 318         if (!*list)
 319                 return -ENOENT;
 320
 321         *cells_size = pinctrl_find_cells_size(np);
 322         if (*cells_size < 0)
 323                 return -ENOENT;
 324
 325         /* First element is always the index within the pinctrl device */
 326         *nr_elements = (size / sizeof(**list)) / (*cells_size + 1);
 327
 328         return 0;
 329 }
 330
 331 /**
 332  * pinctrl_count_index_with_args - Count number of elements in a pinctrl entry
 333  * @np: pointer to device node with the property
 334  * @list_name: property that contains the list
 335  *
 336  * Counts the number of elements in a pinctrl array consisting of an index
 337  * within the controller and a number of u32 entries specified for each
 338  * entry. Note that device_node is always for the parent pin controller device.
 339  */
 340 int pinctrl_count_index_with_args(const struct device_node *np,
 341                                   const char *list_name)
 342 {
 343         const __be32 *list;
 344         int size, nr_cells, error;
 345
 346         error = pinctrl_get_list_and_count(np, list_name, &list,
 347                                            &nr_cells, &size);
 348         if (error)
 349                 return error;
 350
 351         return size;
 352 }
 353 EXPORT_SYMBOL_GPL(pinctrl_count_index_with_args);
 354
 355 /**
 356  * pinctrl_copy_args - Populates of_phandle_args based on index
 357  * @np: pointer to device node with the property
 358  * @list: pointer to a list with the elements
 359  * @index: entry within the list of elements
 360  * @nr_cells: number of cells in the list
 361  * @nr_elem: number of elements for each entry in the list
 362  * @out_args: returned values
 363  *
 364  * Populates the of_phandle_args based on the index in the list.
 365  */
 366 static int pinctrl_copy_args(const struct device_node *np,
 367                              const __be32 *list,
 368                              int index, int nr_cells, int nr_elem,
 369                              struct of_phandle_args *out_args)
 370 {
 371         int i;
 372
 373         memset(out_args, 0, sizeof(*out_args));
 374         out_args->np = (struct device_node *)np;
 375         out_args->args_count = nr_cells + 1;
 376
 377         if (index >= nr_elem)
 378                 return -EINVAL;
 379
 380         list += index * (nr_cells + 1);
 381
 382         for (i = 0; i < nr_cells + 1; i++)
 383                 out_args->args[i] = be32_to_cpup(list++);
 384
 385         return 0;
 386 }
 387
 388 /**
 389  * pinctrl_parse_index_with_args - Find a node pointed by index in a list
 390  * @np: pointer to device node with the property
 391  * @list_name: property that contains the list
 392  * @index: index within the list
 393  * @out_arts: entries in the list pointed by index
 394  *
 395  * Finds the selected element in a pinctrl array consisting of an index
 396  * within the controller and a number of u32 entries specified for each
 397  * entry. Note that device_node is always for the parent pin controller device.
 398  */
 399 int pinctrl_parse_index_with_args(const struct device_node *np,
 400                                   const char *list_name, int index,
 401                                   struct of_phandle_args *out_args)
 402 {
 403         const __be32 *list;
 404         int nr_elem, nr_cells, error;
 405
 406         error = pinctrl_get_list_and_count(np, list_name, &list,
 407                                            &nr_cells, &nr_elem);
 408         if (error || !nr_cells)
 409                 return error;
 410
 411         error = pinctrl_copy_args(np, list, index, nr_cells, nr_elem,
 412                                   out_args);
 413         if (error)
 414                 return error;
 415
 416         return 0;
 417 }
 418 EXPORT_SYMBOL_GPL(pinctrl_parse_index_with_args);