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
dt_free_map(struct pinctrl_dev * pctldev,struct pinctrl_map * map,unsigned num_maps)40 static void dt_free_map(struct pinctrl_dev *pctldev,
41 struct pinctrl_map *map, unsigned num_maps)
42 {
43 int i;
44
45 for (i = 0; i < num_maps; ++i) {
46 kfree_const(map[i].dev_name);
47 map[i].dev_name = NULL;
48 }
49
50 if (pctldev) {
51 const struct pinctrl_ops *ops = pctldev->desc->pctlops;
52 ops->dt_free_map(pctldev, map, num_maps);
53 } else {
54 /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
55 kfree(map);
56 }
57 }
58
pinctrl_dt_free_maps(struct pinctrl * p)59 void pinctrl_dt_free_maps(struct pinctrl *p)
60 {
61 struct pinctrl_dt_map *dt_map, *n1;
62
63 list_for_each_entry_safe(dt_map, n1, &p->dt_maps, node) {
64 pinctrl_unregister_map(dt_map->map);
65 list_del(&dt_map->node);
66 dt_free_map(dt_map->pctldev, dt_map->map,
67 dt_map->num_maps);
68 kfree(dt_map);
69 }
70
71 of_node_put(p->dev->of_node);
72 }
73
dt_remember_or_free_map(struct pinctrl * p,const char * statename,struct pinctrl_dev * pctldev,struct pinctrl_map * map,unsigned num_maps)74 static int dt_remember_or_free_map(struct pinctrl *p, const char *statename,
75 struct pinctrl_dev *pctldev,
76 struct pinctrl_map *map, unsigned num_maps)
77 {
78 int i;
79 struct pinctrl_dt_map *dt_map;
80
81 /* Initialize common mapping table entry fields */
82 for (i = 0; i < num_maps; i++) {
83 const char *devname;
84
85 devname = kstrdup_const(dev_name(p->dev), GFP_KERNEL);
86 if (!devname)
87 goto err_free_map;
88
89 map[i].dev_name = devname;
90 map[i].name = statename;
91 if (pctldev)
92 map[i].ctrl_dev_name = dev_name(pctldev->dev);
93 }
94
95 /* Remember the converted mapping table entries */
96 dt_map = kzalloc(sizeof(*dt_map), GFP_KERNEL);
97 if (!dt_map)
98 goto err_free_map;
99
100 dt_map->pctldev = pctldev;
101 dt_map->map = map;
102 dt_map->num_maps = num_maps;
103 list_add_tail(&dt_map->node, &p->dt_maps);
104
105 return pinctrl_register_map(map, num_maps, false);
106
107 err_free_map:
108 dt_free_map(pctldev, map, num_maps);
109 return -ENOMEM;
110 }
111
of_pinctrl_get(struct device_node * np)112 struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
113 {
114 return get_pinctrl_dev_from_of_node(np);
115 }
116
dt_to_map_one_config(struct pinctrl * p,const char * statename,struct device_node * np_config)117 static int dt_to_map_one_config(struct pinctrl *p, const char *statename,
118 struct device_node *np_config)
119 {
120 struct device_node *np_pctldev;
121 struct pinctrl_dev *pctldev;
122 const struct pinctrl_ops *ops;
123 int ret;
124 struct pinctrl_map *map;
125 unsigned num_maps;
126
127 /* Find the pin controller containing np_config */
128 np_pctldev = of_node_get(np_config);
129 for (;;) {
130 np_pctldev = of_get_next_parent(np_pctldev);
131 if (!np_pctldev || of_node_is_root(np_pctldev)) {
132 dev_info(p->dev, "could not find pctldev for node %s, deferring probe\n",
133 np_config->full_name);
134 of_node_put(np_pctldev);
135 /* OK let's just assume this will appear later then */
136 return -EPROBE_DEFER;
137 }
138 pctldev = get_pinctrl_dev_from_of_node(np_pctldev);
139 if (pctldev)
140 break;
141 /* Do not defer probing of hogs (circular loop) */
142 if (np_pctldev == p->dev->of_node) {
143 of_node_put(np_pctldev);
144 return -ENODEV;
145 }
146 }
147 of_node_put(np_pctldev);
148
149 /*
150 * Call pinctrl driver to parse device tree node, and
151 * generate mapping table entries
152 */
153 ops = pctldev->desc->pctlops;
154 if (!ops->dt_node_to_map) {
155 dev_err(p->dev, "pctldev %s doesn't support DT\n",
156 dev_name(pctldev->dev));
157 return -ENODEV;
158 }
159 ret = ops->dt_node_to_map(pctldev, np_config, &map, &num_maps);
160 if (ret < 0)
161 return ret;
162
163 /* Stash the mapping table chunk away for later use */
164 return dt_remember_or_free_map(p, statename, pctldev, map, num_maps);
165 }
166
dt_remember_dummy_state(struct pinctrl * p,const char * statename)167 static int dt_remember_dummy_state(struct pinctrl *p, const char *statename)
168 {
169 struct pinctrl_map *map;
170
171 map = kzalloc(sizeof(*map), GFP_KERNEL);
172 if (!map) {
173 dev_err(p->dev, "failed to alloc struct pinctrl_map\n");
174 return -ENOMEM;
175 }
176
177 /* There is no pctldev for PIN_MAP_TYPE_DUMMY_STATE */
178 map->type = PIN_MAP_TYPE_DUMMY_STATE;
179
180 return dt_remember_or_free_map(p, statename, NULL, map, 1);
181 }
182
pinctrl_dt_to_map(struct pinctrl * p)183 int pinctrl_dt_to_map(struct pinctrl *p)
184 {
185 struct device_node *np = p->dev->of_node;
186 int state, ret;
187 char *propname;
188 struct property *prop;
189 const char *statename;
190 const __be32 *list;
191 int size, config;
192 phandle phandle;
193 struct device_node *np_config;
194
195 /* CONFIG_OF enabled, p->dev not instantiated from DT */
196 if (!np) {
197 if (of_have_populated_dt())
198 dev_dbg(p->dev,
199 "no of_node; not parsing pinctrl DT\n");
200 return 0;
201 }
202
203 /* We may store pointers to property names within the node */
204 of_node_get(np);
205
206 /* For each defined state ID */
207 for (state = 0; ; state++) {
208 /* Retrieve the pinctrl-* property */
209 propname = kasprintf(GFP_KERNEL, "pinctrl-%d", state);
210 prop = of_find_property(np, propname, &size);
211 kfree(propname);
212 if (!prop)
213 break;
214 list = prop->value;
215 size /= sizeof(*list);
216
217 /* Determine whether pinctrl-names property names the state */
218 ret = of_property_read_string_index(np, "pinctrl-names",
219 state, &statename);
220 /*
221 * If not, statename is just the integer state ID. But rather
222 * than dynamically allocate it and have to free it later,
223 * just point part way into the property name for the string.
224 */
225 if (ret < 0) {
226 /* strlen("pinctrl-") == 8 */
227 statename = prop->name + 8;
228 }
229
230 /* For every referenced pin configuration node in it */
231 for (config = 0; config < size; config++) {
232 phandle = be32_to_cpup(list++);
233
234 /* Look up the pin configuration node */
235 np_config = of_find_node_by_phandle(phandle);
236 if (!np_config) {
237 dev_err(p->dev,
238 "prop %s index %i invalid phandle\n",
239 prop->name, config);
240 ret = -EINVAL;
241 goto err;
242 }
243
244 /* Parse the node */
245 ret = dt_to_map_one_config(p, statename, np_config);
246 of_node_put(np_config);
247 if (ret < 0)
248 goto err;
249 }
250
251 /* No entries in DT? Generate a dummy state table entry */
252 if (!size) {
253 ret = dt_remember_dummy_state(p, statename);
254 if (ret < 0)
255 goto err;
256 }
257 }
258
259 return 0;
260
261 err:
262 pinctrl_dt_free_maps(p);
263 return ret;
264 }
265