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(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}
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(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}
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(t->owner))
94		t = NULL;
95	mutex_unlock(&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(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;
117out_module_put:
118	module_put(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(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(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
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(&iio_configfs_subsys.su_group,
169						"triggers",
170						&iio_triggers_group_type);
171	return PTR_ERR_OR_ZERO(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(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