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b662f809 DB |
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/configfs.h> | |
19 | ||
20 | static struct config_group *iio_triggers_group; | |
21 | static struct config_item_type iio_trigger_type_group_type; | |
22 | ||
23 | static struct config_item_type iio_triggers_group_type = { | |
24 | .ct_owner = THIS_MODULE, | |
25 | }; | |
26 | ||
27 | static LIST_HEAD(iio_trigger_types_list); | |
28 | static DEFINE_MUTEX(iio_trigger_types_lock); | |
29 | ||
30 | static | |
31 | struct iio_sw_trigger_type *__iio_find_sw_trigger_type(const char *name, | |
32 | unsigned len) | |
33 | { | |
34 | struct iio_sw_trigger_type *t = NULL, *iter; | |
35 | ||
36 | list_for_each_entry(iter, &iio_trigger_types_list, list) | |
37 | if (!strcmp(iter->name, name)) { | |
38 | t = iter; | |
39 | break; | |
40 | } | |
41 | ||
42 | return t; | |
43 | } | |
44 | ||
45 | int iio_register_sw_trigger_type(struct iio_sw_trigger_type *t) | |
46 | { | |
47 | struct iio_sw_trigger_type *iter; | |
48 | int ret = 0; | |
49 | ||
50 | mutex_lock(&iio_trigger_types_lock); | |
51 | iter = __iio_find_sw_trigger_type(t->name, strlen(t->name)); | |
52 | if (iter) | |
53 | ret = -EBUSY; | |
54 | else | |
55 | list_add_tail(&t->list, &iio_trigger_types_list); | |
56 | mutex_unlock(&iio_trigger_types_lock); | |
57 | ||
58 | if (ret) | |
59 | return ret; | |
60 | ||
61 | t->group = configfs_register_default_group(iio_triggers_group, t->name, | |
62 | &iio_trigger_type_group_type); | |
63 | if (IS_ERR(t->group)) | |
64 | ret = PTR_ERR(t->group); | |
65 | ||
66 | return ret; | |
67 | } | |
68 | EXPORT_SYMBOL(iio_register_sw_trigger_type); | |
69 | ||
70 | void iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *t) | |
71 | { | |
72 | struct iio_sw_trigger_type *iter; | |
73 | ||
74 | mutex_lock(&iio_trigger_types_lock); | |
75 | iter = __iio_find_sw_trigger_type(t->name, strlen(t->name)); | |
76 | if (iter) | |
77 | list_del(&t->list); | |
78 | mutex_unlock(&iio_trigger_types_lock); | |
79 | ||
80 | configfs_unregister_default_group(t->group); | |
81 | } | |
82 | EXPORT_SYMBOL(iio_unregister_sw_trigger_type); | |
83 | ||
84 | static | |
85 | struct iio_sw_trigger_type *iio_get_sw_trigger_type(const char *name) | |
86 | { | |
87 | struct iio_sw_trigger_type *t; | |
88 | ||
89 | mutex_lock(&iio_trigger_types_lock); | |
90 | t = __iio_find_sw_trigger_type(name, strlen(name)); | |
91 | if (t && !try_module_get(t->owner)) | |
92 | t = NULL; | |
93 | mutex_unlock(&iio_trigger_types_lock); | |
94 | ||
95 | return t; | |
96 | } | |
97 | ||
98 | struct iio_sw_trigger *iio_sw_trigger_create(const char *type, const char *name) | |
99 | { | |
100 | struct iio_sw_trigger *t; | |
101 | struct iio_sw_trigger_type *tt; | |
102 | ||
103 | tt = iio_get_sw_trigger_type(type); | |
104 | if (!tt) { | |
105 | pr_err("Invalid trigger type: %s\n", type); | |
106 | return ERR_PTR(-EINVAL); | |
107 | } | |
108 | t = tt->ops->probe(name); | |
109 | if (IS_ERR(t)) | |
110 | goto out_module_put; | |
111 | ||
112 | t->trigger_type = tt; | |
113 | ||
114 | return t; | |
115 | out_module_put: | |
116 | module_put(tt->owner); | |
117 | return t; | |
118 | } | |
119 | EXPORT_SYMBOL(iio_sw_trigger_create); | |
120 | ||
121 | void iio_sw_trigger_destroy(struct iio_sw_trigger *t) | |
122 | { | |
123 | struct iio_sw_trigger_type *tt = t->trigger_type; | |
124 | ||
125 | tt->ops->remove(t); | |
126 | module_put(tt->owner); | |
127 | } | |
128 | EXPORT_SYMBOL(iio_sw_trigger_destroy); | |
129 | ||
130 | static struct config_group *trigger_make_group(struct config_group *group, | |
131 | const char *name) | |
132 | { | |
133 | struct iio_sw_trigger *t; | |
134 | ||
135 | t = iio_sw_trigger_create(group->cg_item.ci_name, name); | |
136 | if (IS_ERR(t)) | |
137 | return ERR_CAST(t); | |
138 | ||
139 | config_item_set_name(&t->group.cg_item, "%s", name); | |
140 | ||
141 | return &t->group; | |
142 | } | |
143 | ||
144 | static void trigger_drop_group(struct config_group *group, | |
145 | struct config_item *item) | |
146 | { | |
147 | struct iio_sw_trigger *t = to_iio_sw_trigger(item); | |
148 | ||
149 | iio_sw_trigger_destroy(t); | |
150 | config_item_put(item); | |
151 | } | |
152 | ||
153 | static struct configfs_group_operations trigger_ops = { | |
154 | .make_group = &trigger_make_group, | |
155 | .drop_item = &trigger_drop_group, | |
156 | }; | |
157 | ||
158 | static struct config_item_type iio_trigger_type_group_type = { | |
159 | .ct_group_ops = &trigger_ops, | |
160 | .ct_owner = THIS_MODULE, | |
161 | }; | |
162 | ||
163 | static int __init iio_sw_trigger_init(void) | |
164 | { | |
165 | iio_triggers_group = | |
166 | configfs_register_default_group(&iio_configfs_subsys.su_group, | |
167 | "triggers", | |
168 | &iio_triggers_group_type); | |
169 | if (IS_ERR(iio_triggers_group)) | |
170 | return PTR_ERR(iio_triggers_group); | |
171 | return 0; | |
172 | } | |
173 | module_init(iio_sw_trigger_init); | |
174 | ||
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"); |