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 |
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 | |
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(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 | } |
70 | EXPORT_SYMBOL(iio_register_sw_trigger_type); |
71 | |
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(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 | } |
84 | EXPORT_SYMBOL(iio_unregister_sw_trigger_type); |
85 | |
86 | static |
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(module: t->owner)) |
94 | t = NULL; |
95 | mutex_unlock(lock: &iio_trigger_types_lock); |
96 | |
97 | return t; |
98 | } |
99 | |
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(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; |
117 | out_module_put: |
118 | module_put(module: tt->owner); |
119 | return t; |
120 | } |
121 | EXPORT_SYMBOL(iio_sw_trigger_create); |
122 | |
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(module: tt->owner); |
129 | } |
130 | EXPORT_SYMBOL(iio_sw_trigger_destroy); |
131 | |
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(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 | |
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 | |
165 | static 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 | } |
173 | module_init(iio_sw_trigger_init); |
174 | |
175 | static void __exit iio_sw_trigger_exit(void) |
176 | { |
177 | configfs_unregister_default_group(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 | |