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 */
33struct pinctrl_dt_map {
34	struct list_head node;
35	struct pinctrl_dev *pctldev;
36	struct pinctrl_map *map;
37	unsigned num_maps;
38};
39
40static 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
52void 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
67static 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
98struct pinctrl_dev *of_pinctrl_get(struct device_node *np)
99{
100	return get_pinctrl_dev_from_of_node(np);
101}
102
103static 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
153static 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
169int 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			break;
200		list = prop->value;
201		size /= sizeof(*list);
202
203		/* Determine whether pinctrl-names property names the state */
204		ret = of_property_read_string_index(np, "pinctrl-names",
205						    state, &statename);
206		/*
207		 * If not, statename is just the integer state ID. But rather
208		 * than dynamically allocate it and have to free it later,
209		 * just point part way into the property name for the string.
210		 */
211		if (ret < 0) {
212			/* strlen("pinctrl-") == 8 */
213			statename = prop->name + 8;
214		}
215
216		/* For every referenced pin configuration node in it */
217		for (config = 0; config < size; config++) {
218			phandle = be32_to_cpup(list++);
219
220			/* Look up the pin configuration node */
221			np_config = of_find_node_by_phandle(phandle);
222			if (!np_config) {
223				dev_err(p->dev,
224					"prop %s index %i invalid phandle\n",
225					prop->name, config);
226				ret = -EINVAL;
227				goto err;
228			}
229
230			/* Parse the node */
231			ret = dt_to_map_one_config(p, statename, np_config);
232			of_node_put(np_config);
233			if (ret < 0)
234				goto err;
235		}
236
237		/* No entries in DT? Generate a dummy state table entry */
238		if (!size) {
239			ret = dt_remember_dummy_state(p, statename);
240			if (ret < 0)
241				goto err;
242		}
243	}
244
245	return 0;
246
247err:
248	pinctrl_dt_free_maps(p);
249	return ret;
250}
251