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                 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);
  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, const char *statename,
 104                                 struct device_node *np_config)
 105 {
 106         struct device_node *np_pctldev;
 107         struct pinctrl_dev *pctldev;
 108         const struct pinctrl_ops *ops;
 109         int ret;
 110         struct pinctrl_map *map;
 111         unsigned num_maps;
 112
 113         /* Find the pin controller containing np_config */
 114         np_pctldev = of_node_get(np_config);
 115         for (;;) {
 116                 np_pctldev = of_get_next_parent(np_pctldev);
 117                 if (!np_pctldev || of_node_is_root(np_pctldev)) {
 118                         dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n",
 119                                 np_config->full_name);
 120                         of_node_put(np_pctldev);
 121                         /* OK let's just assume this will appear later then */
 122                         return -EPROBE_DEFER;
 123                 }
 124                 pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
 125                 if (pctldev)
 126                         break;
 127                 /* Do not defer probing of hogs (circular loop) */
 128                 if (np_pctldev == p->dev->of_node) {
 129                         of_node_put(np_pctldev);
 130                         return -ENODEV;
 131                 }
 132         }
 133         of_node_put(np_pctldev);
 134
 135         /*
 136          * Call pinctrl driver to parse device tree node, and
 137          * generate mapping table entries
 138          */
 139         ops = pctldev->desc->pctlops;
 140         if (!ops->dt_node_to_map) {
 141                 dev_err(p->dev, "pctldev %s doesn't support DT\n",
 142                         dev_name(pctldev->dev));
 143                 return -ENODEV;
 144         }
 145         ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
 146         if (ret < 0)
 147                 return ret;
 148
 149         /* Stash the mapping table chunk away for later use */
 150         return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
 151 }
 152
 153 static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
 154 {
 155         struct pinctrl_map *map;
 156
 157         map = kzalloc(sizeof(*map), GFP_KERNEL);
 158         if (!map) {
 159                 dev_err(p->dev, "failed to alloc struct pinctrl_map\n");
 160                 return -ENOMEM;
 161         }
 162
 163         /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
 164         map->type = PIN_MAP_TYPE_DUMMY_STATE;
 165
 166         return dt_remember_or_free_map(p, statename, NULL, map, 1);
 167 }
 168
 169 int pinctrl_dt_to_map(struct pinctrl *p)
 170 {
 171         struct device_node *np = p->dev->of_node;
 172         int state, ret;
 173         char *propname;
 174         struct property *prop;
 175         const char *statename;
 176         const __be32 *list;
 177         int size, config;
 178         phandle phandle;
 179         struct device_node *np_config;
 180
 181         /* CONFIG_OF enabled, p->dev not instantiated from DT */
 182         if (!np) {
 183                 if (of_have_populated_dt())
 184                         dev_dbg(p->dev,
 185                                 "no of_node; not parsing pinctrl DT\n");
 186                 return 0;
 187         }
 188
 189         /* We may store pointers to property names within the node */
 190         of_node_get(np);
 191
 192         /* For each defined state ID */
 193         for (state = 0; ; state++) {
 194                 /* Retrieve the pinctrl-* property */
 195                 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
 196                 prop = of_find_property(np, propname, &size);
 197                 kfree(propname);
 198                 if (!prop) {
 199                         if (state == 0) {
 200                                 of_node_put(np);
 201                                 return -ENODEV;
 202                         }
 203                         break;
 204                 }
 205                 list = prop->value;
 206                 size /= sizeof(*list);
 207
 208                 /* Determine whether pinctrl-names property names the state */
 209                 ret = of_property_read_string_index(np, "pinctrl-names",
 210                                                     state, &statename);
 211                 /*
 212                  * If not, statename is just the integer state ID. But rather
 213                  * than dynamically allocate it and have to free it later,
 214                  * just point part way into the property name for the string.
 215                  */
 216                 if (ret < 0) {
 217                         /* strlen("pinctrl-") == 8 */
 218                         statename = prop->name + 8;
 219                 }
 220
 221                 /* For every referenced pin configuration node in it */
 222                 for (config = 0; config < size; config++) {
 223                         phandle = be32_to_cpup(list++);
 224
 225                         /* Look up the pin configuration node */
 226                         np_config = of_find_node_by_phandle(phandle);
 227                         if (!np_config) {
 228                                 dev_err(p->dev,
 229                                         "prop %s index %i invalid phandle\n",
 230                                         prop->name, config);
 231                                 ret = -EINVAL;
 232                                 goto err;
 233                         }
 234
 235                         /* Parse the node */
 236                         ret = dt_to_map_one_config(p, statename, np_config);
 237                         of_node_put(np_config);
 238                         if (ret < 0)
 239                                 goto err;
 240                 }
 241
 242                 /* No entries in DT? Generate a dummy state table entry */
 243                 if (!size) {
 244                         ret = dt_remember_dummy_state(p, statename);
 245                         if (ret < 0)
 246                                 goto err;
 247                 }
 248         }
 249
 250         return 0;
 251
 252 err:
 253         pinctrl_dt_free_maps(p);
 254         return ret;
 255 }