tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * The Industrial I/O core, software trigger functions
3 *
4 * Copyright (c) 2015 Intel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published by
8 * the Free Software Foundation.
9 */
10
11#include <linux/module.h>
12#include <linux/init.h>
13#include <linux/kmod.h>
14#include <linux/list.h>
15#include <linux/slab.h>
16
17#include <linux/iio/sw_trigger.h>
18#include <linux/iio/configfs.h>
19#include <linux/configfs.h>
20
21static struct config_group *iio_triggers_group;
22static const struct config_item_type iio_trigger_type_group_type;
23
24static const struct config_item_type iio_triggers_group_type = {
25 .ct_owner = THIS_MODULE,
26};
27
28static LIST_HEAD(iio_trigger_types_list);
29static DEFINE_MUTEX(iio_trigger_types_lock);
30
31static
32struct iio_sw_trigger_type *__iio_find_sw_trigger_type(const char *name,
33 unsigned len)
34{
35 struct iio_sw_trigger_type *t = NULL, *iter;
36
37 list_for_each_entry(iter, &iio_trigger_types_list, list)
38 if (!strcmp(iter->name, name)) {
39 t = iter;
40 break;
41 }
42
43 return t;
44}
45
46int iio_register_sw_trigger_type(struct iio_sw_trigger_type *t)
47{
48 struct iio_sw_trigger_type *iter;
49 int ret = 0;
50
51 mutex_lock(&iio_trigger_types_lock);
52 iter = __iio_find_sw_trigger_type(t->name, strlen(t->name));
53 if (iter)
54 ret = -EBUSY;
55 else
56 list_add_tail(&t->list, &iio_trigger_types_list);
57 mutex_unlock(&iio_trigger_types_lock);
58
59 if (ret)
60 return ret;
61
62 t->group = configfs_register_default_group(iio_triggers_group, t->name,
63 &iio_trigger_type_group_type);
64 if (IS_ERR(t->group))
65 ret = PTR_ERR(t->group);
66
67 return ret;
68}
69EXPORT_SYMBOL(iio_register_sw_trigger_type);
70
71void iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *t)
72{
73 struct iio_sw_trigger_type *iter;
74
75 mutex_lock(&iio_trigger_types_lock);
76 iter = __iio_find_sw_trigger_type(t->name, strlen(t->name));
77 if (iter)
78 list_del(&t->list);
79 mutex_unlock(&iio_trigger_types_lock);
80
81 configfs_unregister_default_group(t->group);
82}
83EXPORT_SYMBOL(iio_unregister_sw_trigger_type);
84
85static
86struct iio_sw_trigger_type *iio_get_sw_trigger_type(const char *name)
87{
88 struct iio_sw_trigger_type *t;
89
90 mutex_lock(&iio_trigger_types_lock);
91 t = __iio_find_sw_trigger_type(name, strlen(name));
92 if (t && !try_module_get(t->owner))
93 t = NULL;
94 mutex_unlock(&iio_trigger_types_lock);
95
96 return t;
97}
98
99struct iio_sw_trigger *iio_sw_trigger_create(const char *type, const char *name)
100{
101 struct iio_sw_trigger *t;
102 struct iio_sw_trigger_type *tt;
103
104 tt = iio_get_sw_trigger_type(type);
105 if (!tt) {
106 pr_err("Invalid trigger type: %s\n", type);
107 return ERR_PTR(-EINVAL);
108 }
109 t = tt->ops->probe(name);
110 if (IS_ERR(t))
111 goto out_module_put;
112
113 t->trigger_type = tt;
114
115 return t;
116out_module_put:
117 module_put(tt->owner);
118 return t;
119}
120EXPORT_SYMBOL(iio_sw_trigger_create);
121
122void iio_sw_trigger_destroy(struct iio_sw_trigger *t)
123{
124 struct iio_sw_trigger_type *tt = t->trigger_type;
125
126 tt->ops->remove(t);
127 module_put(tt->owner);
128}
129EXPORT_SYMBOL(iio_sw_trigger_destroy);
130
131static struct config_group *trigger_make_group(struct config_group *group,
132 const char *name)
133{
134 struct iio_sw_trigger *t;
135
136 t = iio_sw_trigger_create(group->cg_item.ci_name, name);
137 if (IS_ERR(t))
138 return ERR_CAST(t);
139
140 config_item_set_name(&t->group.cg_item, "%s", name);
141
142 return &t->group;
143}
144
145static void trigger_drop_group(struct config_group *group,
146 struct config_item *item)
147{
148 struct iio_sw_trigger *t = to_iio_sw_trigger(item);
149
150 iio_sw_trigger_destroy(t);
151 config_item_put(item);
152}
153
154static struct configfs_group_operations trigger_ops = {
155 .make_group = &trigger_make_group,
156 .drop_item = &trigger_drop_group,
157};
158
159static const struct config_item_type iio_trigger_type_group_type = {
160 .ct_group_ops = &trigger_ops,
161 .ct_owner = THIS_MODULE,
162};
163
164static int __init iio_sw_trigger_init(void)
165{
166 iio_triggers_group =
167 configfs_register_default_group(&iio_configfs_subsys.su_group,
168 "triggers",
169 &iio_triggers_group_type);
170 return PTR_ERR_OR_ZERO(iio_triggers_group);
171}
172module_init(iio_sw_trigger_init);
173
174static void __exit iio_sw_trigger_exit(void)
175{
176 configfs_unregister_default_group(iio_triggers_group);
177}
178module_exit(iio_sw_trigger_exit);
179
180MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
181MODULE_DESCRIPTION("Industrial I/O software triggers support");
182MODULE_LICENSE("GPL v2");