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 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		ret = PTR_ERR(t->group);
 63
 64	return ret;
 65}
 66EXPORT_SYMBOL(iio_register_sw_trigger_type);
 67
 68void iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *t)
 69{
 70	struct iio_sw_trigger_type *iter;
 71
 72	mutex_lock(&iio_trigger_types_lock);
 73	iter = __iio_find_sw_trigger_type(t->name, strlen(t->name));
 74	if (iter)
 75		list_del(&t->list);
 76	mutex_unlock(&iio_trigger_types_lock);
 77
 78	configfs_unregister_default_group(t->group);
 79}
 80EXPORT_SYMBOL(iio_unregister_sw_trigger_type);
 81
 82static
 83struct iio_sw_trigger_type *iio_get_sw_trigger_type(const char *name)
 84{
 85	struct iio_sw_trigger_type *t;
 86
 87	mutex_lock(&iio_trigger_types_lock);
 88	t = __iio_find_sw_trigger_type(name, strlen(name));
 89	if (t && !try_module_get(t->owner))
 90		t = NULL;
 91	mutex_unlock(&iio_trigger_types_lock);
 92
 93	return t;
 94}
 95
 96struct iio_sw_trigger *iio_sw_trigger_create(const char *type, const char *name)
 97{
 98	struct iio_sw_trigger *t;
 99	struct iio_sw_trigger_type *tt;
100
101	tt = iio_get_sw_trigger_type(type);
102	if (!tt) {
103		pr_err("Invalid trigger type: %s\n", type);
104		return ERR_PTR(-EINVAL);
105	}
106	t = tt->ops->probe(name);
107	if (IS_ERR(t))
108		goto out_module_put;
109
110	t->trigger_type = tt;
111
112	return t;
113out_module_put:
114	module_put(tt->owner);
115	return t;
116}
117EXPORT_SYMBOL(iio_sw_trigger_create);
118
119void iio_sw_trigger_destroy(struct iio_sw_trigger *t)
120{
121	struct iio_sw_trigger_type *tt = t->trigger_type;
122
123	tt->ops->remove(t);
124	module_put(tt->owner);
125}
126EXPORT_SYMBOL(iio_sw_trigger_destroy);
127
128static struct config_group *trigger_make_group(struct config_group *group,
129					       const char *name)
130{
131	struct iio_sw_trigger *t;
132
133	t = iio_sw_trigger_create(group->cg_item.ci_name, name);
134	if (IS_ERR(t))
135		return ERR_CAST(t);
136
137	config_item_set_name(&t->group.cg_item, "%s", name);
138
139	return &t->group;
140}
141
142static void trigger_drop_group(struct config_group *group,
143			       struct config_item *item)
144{
145	struct iio_sw_trigger *t = to_iio_sw_trigger(item);
146
147	iio_sw_trigger_destroy(t);
148	config_item_put(item);
149}
150
151static struct configfs_group_operations trigger_ops = {
152	.make_group	= &trigger_make_group,
153	.drop_item	= &trigger_drop_group,
154};
155
156static const struct config_item_type iio_trigger_type_group_type = {
157	.ct_group_ops = &trigger_ops,
158	.ct_owner       = THIS_MODULE,
159};
160
161static int __init iio_sw_trigger_init(void)
162{
163	iio_triggers_group =
164		configfs_register_default_group(&iio_configfs_subsys.su_group,
165						"triggers",
166						&iio_triggers_group_type);
167	return PTR_ERR_OR_ZERO(iio_triggers_group);
168}
169module_init(iio_sw_trigger_init);
170
171static void __exit iio_sw_trigger_exit(void)
172{
173	configfs_unregister_default_group(iio_triggers_group);
174}
175module_exit(iio_sw_trigger_exit);
176
177MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
178MODULE_DESCRIPTION("Industrial I/O software triggers support");
179MODULE_LICENSE("GPL v2");