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