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");