1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * The Industrial I/O core, software trigger functions
4 *
5 * Copyright (c) 2015 Intel Corporation
6 */
7
8#include <linux/module.h>
9#include <linux/init.h>
10#include <linux/kmod.h>
11#include <linux/list.h>
12#include <linux/slab.h>
13
14#include <linux/iio/sw_trigger.h>
15#include <linux/iio/configfs.h>
16#include <linux/configfs.h>
17
18static struct config_group *iio_triggers_group;
19static const struct config_item_type iio_trigger_type_group_type;
20
21static const struct config_item_type iio_triggers_group_type = {
22 .ct_owner = THIS_MODULE,
23};
24
25static LIST_HEAD(iio_trigger_types_list);
26static DEFINE_MUTEX(iio_trigger_types_lock);
27
28static
29struct iio_sw_trigger_type *__iio_find_sw_trigger_type(const char *name,
30 unsigned int len)
31{
32 struct iio_sw_trigger_type *t = NULL, *iter;
33
34 list_for_each_entry(iter, &iio_trigger_types_list, list)
35 if (!strcmp(iter->name, name)) {
36 t = iter;
37 break;
38 }
39
40 return t;
41}
42
43int iio_register_sw_trigger_type(struct iio_sw_trigger_type *t)
44{
45 struct iio_sw_trigger_type *iter;
46 int ret = 0;
47
48 mutex_lock(&iio_trigger_types_lock);
49 iter = __iio_find_sw_trigger_type(name: t->name, strlen(t->name));
50 if (iter)
51 ret = -EBUSY;
52 else
53 list_add_tail(new: &t->list, head: &iio_trigger_types_list);
54 mutex_unlock(lock: &iio_trigger_types_lock);
55
56 if (ret)
57 return ret;
58
59 t->group = configfs_register_default_group(parent_group: iio_triggers_group, name: t->name,
60 item_type: &iio_trigger_type_group_type);
61 if (IS_ERR(ptr: t->group)) {
62 mutex_lock(&iio_trigger_types_lock);
63 list_del(entry: &t->list);
64 mutex_unlock(lock: &iio_trigger_types_lock);
65 ret = PTR_ERR(ptr: t->group);
66 }
67
68 return ret;
69}
70EXPORT_SYMBOL(iio_register_sw_trigger_type);
71
72void iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *t)
73{
74 struct iio_sw_trigger_type *iter;
75
76 mutex_lock(&iio_trigger_types_lock);
77 iter = __iio_find_sw_trigger_type(name: t->name, strlen(t->name));
78 if (iter)
79 list_del(entry: &t->list);
80 mutex_unlock(lock: &iio_trigger_types_lock);
81
82 configfs_unregister_default_group(group: t->group);
83}
84EXPORT_SYMBOL(iio_unregister_sw_trigger_type);
85
86static
87struct iio_sw_trigger_type *iio_get_sw_trigger_type(const char *name)
88{
89 struct iio_sw_trigger_type *t;
90
91 mutex_lock(&iio_trigger_types_lock);
92 t = __iio_find_sw_trigger_type(name, strlen(name));
93 if (t && !try_module_get(module: t->owner))
94 t = NULL;
95 mutex_unlock(lock: &iio_trigger_types_lock);
96
97 return t;
98}
99
100struct iio_sw_trigger *iio_sw_trigger_create(const char *type, const char *name)
101{
102 struct iio_sw_trigger *t;
103 struct iio_sw_trigger_type *tt;
104
105 tt = iio_get_sw_trigger_type(name: type);
106 if (!tt) {
107 pr_err("Invalid trigger type: %s\n", type);
108 return ERR_PTR(error: -EINVAL);
109 }
110 t = tt->ops->probe(name);
111 if (IS_ERR(ptr: t))
112 goto out_module_put;
113
114 t->trigger_type = tt;
115
116 return t;
117out_module_put:
118 module_put(module: tt->owner);
119 return t;
120}
121EXPORT_SYMBOL(iio_sw_trigger_create);
122
123void iio_sw_trigger_destroy(struct iio_sw_trigger *t)
124{
125 struct iio_sw_trigger_type *tt = t->trigger_type;
126
127 tt->ops->remove(t);
128 module_put(module: tt->owner);
129}
130EXPORT_SYMBOL(iio_sw_trigger_destroy);
131
132static struct config_group *trigger_make_group(struct config_group *group,
133 const char *name)
134{
135 struct iio_sw_trigger *t;
136
137 t = iio_sw_trigger_create(group->cg_item.ci_name, name);
138 if (IS_ERR(ptr: t))
139 return ERR_CAST(ptr: t);
140
141 config_item_set_name(&t->group.cg_item, "%s", name);
142
143 return &t->group;
144}
145
146static void trigger_drop_group(struct config_group *group,
147 struct config_item *item)
148{
149 struct iio_sw_trigger *t = to_iio_sw_trigger(item);
150
151 iio_sw_trigger_destroy(t);
152 config_item_put(item);
153}
154
155static struct configfs_group_operations trigger_ops = {
156 .make_group = &trigger_make_group,
157 .drop_item = &trigger_drop_group,
158};
159
160static const struct config_item_type iio_trigger_type_group_type = {
161 .ct_group_ops = &trigger_ops,
162 .ct_owner = THIS_MODULE,
163};
164
165static int __init iio_sw_trigger_init(void)
166{
167 iio_triggers_group =
168 configfs_register_default_group(parent_group: &iio_configfs_subsys.su_group,
169 name: "triggers",
170 item_type: &iio_triggers_group_type);
171 return PTR_ERR_OR_ZERO(ptr: iio_triggers_group);
172}
173module_init(iio_sw_trigger_init);
174
175static void __exit iio_sw_trigger_exit(void)
176{
177 configfs_unregister_default_group(group: iio_triggers_group);
178}
179module_exit(iio_sw_trigger_exit);
180
181MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
182MODULE_DESCRIPTION("Industrial I/O software triggers support");
183MODULE_LICENSE("GPL v2");
184

source code of linux/drivers/iio/industrialio-sw-trigger.c