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, true);
96}
97
98struct 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
109static 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
159static 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
175int 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
253err:
254	pinctrl_dt_free_maps(p);
255	return ret;
256}
257