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
18 static struct config_group *iio_triggers_group;
19 static const struct config_item_type iio_trigger_type_group_type;
20
21 static const struct config_item_type iio_triggers_group_type = {
22 .ct_owner = THIS_MODULE,
23 };
24
25 static LIST_HEAD(iio_trigger_types_list);
26 static DEFINE_MUTEX(iio_trigger_types_lock);
27
28 static
__iio_find_sw_trigger_type(const char * name,unsigned int len)29 struct 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
iio_register_sw_trigger_type(struct iio_sw_trigger_type * t)43 int 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(t->name, strlen(t->name));
50 if (iter)
51 ret = -EBUSY;
52 else
53 list_add_tail(&t->list, &iio_trigger_types_list);
54 mutex_unlock(&iio_trigger_types_lock);
55
56 if (ret)
57 return ret;
58
59 t->group = configfs_register_default_group(iio_triggers_group, t->name,
60 &iio_trigger_type_group_type);
61 if (IS_ERR(t->group)) {
62 mutex_lock(&iio_trigger_types_lock);
63 list_del(&t->list);
64 mutex_unlock(&iio_trigger_types_lock);
65 ret = PTR_ERR(t->group);
66 }
67
68 return ret;
69 }
70 EXPORT_SYMBOL(iio_register_sw_trigger_type);
71
iio_unregister_sw_trigger_type(struct iio_sw_trigger_type * t)72 void 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(t->name, strlen(t->name));
78 if (iter)
79 list_del(&t->list);
80 mutex_unlock(&iio_trigger_types_lock);
81
82 configfs_unregister_default_group(t->group);
83 }
84 EXPORT_SYMBOL(iio_unregister_sw_trigger_type);
85
86 static
iio_get_sw_trigger_type(const char * name)87 struct 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(t->owner))
94 t = NULL;
95 mutex_unlock(&iio_trigger_types_lock);
96
97 return t;
98 }
99
iio_sw_trigger_create(const char * type,const char * name)100 struct 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(type);
106 if (!tt) {
107 pr_err("Invalid trigger type: %s\n", type);
108 return ERR_PTR(-EINVAL);
109 }
110 t = tt->ops->probe(name);
111 if (IS_ERR(t))
112 goto out_module_put;
113
114 t->trigger_type = tt;
115
116 return t;
117 out_module_put:
118 module_put(tt->owner);
119 return t;
120 }
121 EXPORT_SYMBOL(iio_sw_trigger_create);
122
iio_sw_trigger_destroy(struct iio_sw_trigger * t)123 void 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(tt->owner);
129 }
130 EXPORT_SYMBOL(iio_sw_trigger_destroy);
131
trigger_make_group(struct config_group * group,const char * name)132 static 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(t))
139 return ERR_CAST(t);
140
141 config_item_set_name(&t->group.cg_item, "%s", name);
142
143 return &t->group;
144 }
145
trigger_drop_group(struct config_group * group,struct config_item * item)146 static 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
155 static struct configfs_group_operations trigger_ops = {
156 .make_group = &trigger_make_group,
157 .drop_item = &trigger_drop_group,
158 };
159
160 static const struct config_item_type iio_trigger_type_group_type = {
161 .ct_group_ops = &trigger_ops,
162 .ct_owner = THIS_MODULE,
163 };
164
iio_sw_trigger_init(void)165 static int __init iio_sw_trigger_init(void)
166 {
167 iio_triggers_group =
168 configfs_register_default_group(&iio_configfs_subsys.su_group,
169 "triggers",
170 &iio_triggers_group_type);
171 return PTR_ERR_OR_ZERO(iio_triggers_group);
172 }
173 module_init(iio_sw_trigger_init);
174
iio_sw_trigger_exit(void)175 static void __exit iio_sw_trigger_exit(void)
176 {
177 configfs_unregister_default_group(iio_triggers_group);
178 }
179 module_exit(iio_sw_trigger_exit);
180
181 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
182 MODULE_DESCRIPTION("Industrial I/O software triggers support");
183 MODULE_LICENSE("GPL v2");
184