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 struct pinctrl_dev *of_pinctrl_get(struct device_node *np) 110 { 111 struct pinctrl_dev *pctldev; 112 113 pctldev = find_pinctrl_by_of_node(np); 114 if (!pctldev) 115 return NULL; 116 117 return pctldev; 118 } 119 120 static int dt_to_map_one_config(struct pinctrl *p, const char *statename, 121 struct device_node *np_config) 122 { 123 struct device_node *np_pctldev; 124 struct pinctrl_dev *pctldev; 125 struct pinctrl_ops *ops; 126 int ret; 127 struct pinctrl_map *map; 128 unsigned num_maps; 129 130 /* Find the pin controller containing np_config */ 131 np_pctldev = of_node_get(np_config); 132 for (;;) { 133 np_pctldev = of_get_next_parent(np_pctldev); 134 if (!np_pctldev || of_node_is_root(np_pctldev)) { 135 dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n", 136 np_config->full_name); 137 of_node_put(np_pctldev); 138 /* OK let's just assume this will appear later then */ 139 return -EPROBE_DEFER; 140 } 141 pctldev = find_pinctrl_by_of_node(np_pctldev); 142 if (pctldev) 143 break; 144 /* Do not defer probing of hogs (circular loop) */ 145 if (np_pctldev == p->dev->of_node) { 146 of_node_put(np_pctldev); 147 return -ENODEV; 148 } 149 } 150 of_node_put(np_pctldev); 151 152 /* 153 * Call pinctrl driver to parse device tree node, and 154 * generate mapping table entries 155 */ 156 ops = pctldev->desc->pctlops; 157 if (!ops->dt_node_to_map) { 158 dev_err(p->dev, "pctldev %s doesn't support DT\n", 159 dev_name(pctldev->dev)); 160 return -ENODEV; 161 } 162 ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps); 163 if (ret < 0) 164 return ret; 165 166 /* Stash the mapping table chunk away for later use */ 167 return dt_remember_or_free_map(p, statename, pctldev, map, num_maps); 168 } 169 170 static int dt_remember_dummy_state(struct pinctrl *p, const char *statename) 171 { 172 struct pinctrl_map *map; 173 174 map = kzalloc(sizeof(*map), GFP_KERNEL); 175 if (!map) { 176 dev_err(p->dev, "failed to alloc struct pinctrl_map\n"); 177 return -ENOMEM; 178 } 179 180 /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */ 181 map->type = PIN_MAP_TYPE_DUMMY_STATE; 182 183 return dt_remember_or_free_map(p, statename, NULL, map, 1); 184 } 185 186 int pinctrl_dt_to_map(struct pinctrl *p) 187 { 188 struct device_node *np = p->dev->of_node; 189 int state, ret; 190 char *propname; 191 struct property *prop; 192 const char *statename; 193 const __be32 *list; 194 int size, config; 195 phandle phandle; 196 struct device_node *np_config; 197 198 /* CONFIG_OF enabled, p->dev not instantiated from DT */ 199 if (!np) { 200 dev_dbg(p->dev, "no of_node; not parsing pinctrl DT\n"); 201 return 0; 202 } 203 204 /* We may store pointers to property names within the node */ 205 of_node_get(np); 206 207 /* For each defined state ID */ 208 for (state = 0; ; state++) { 209 /* Retrieve the pinctrl-* property */ 210 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state); 211 prop = of_find_property(np, propname, &size); 212 kfree(propname); 213 if (!prop) 214 break; 215 list = prop->value; 216 size /= sizeof(*list); 217 218 /* Determine whether pinctrl-names property names the state */ 219 ret = of_property_read_string_index(np, "pinctrl-names", 220 state, &statename); 221 /* 222 * If not, statename is just the integer state ID. But rather 223 * than dynamically allocate it and have to free it later, 224 * just point part way into the property name for the string. 225 */ 226 if (ret < 0) { 227 /* strlen("pinctrl-") == 8 */ 228 statename = prop->name + 8; 229 } 230 231 /* For every referenced pin configuration node in it */ 232 for (config = 0; config < size; config++) { 233 phandle = be32_to_cpup(list++); 234 235 /* Look up the pin configuration node */ 236 np_config = of_find_node_by_phandle(phandle); 237 if (!np_config) { 238 dev_err(p->dev, 239 "prop %s index %i invalid phandle\n", 240 prop->name, config); 241 ret = -EINVAL; 242 goto err; 243 } 244 245 /* Parse the node */ 246 ret = dt_to_map_one_config(p, statename, np_config); 247 of_node_put(np_config); 248 if (ret < 0) 249 goto err; 250 } 251 252 /* No entries in DT? Generate a dummy state table entry */ 253 if (!size) { 254 ret = dt_remember_dummy_state(p, statename); 255 if (ret < 0) 256 goto err; 257 } 258 } 259 260 return 0; 261 262 err: 263 pinctrl_dt_free_maps(p); 264 return ret; 265 } 266