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