1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * The Industrial I/O core, software IIO devices functions
4 *
5 * Copyright (c) 2016 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_device.h>
15#include <linux/iio/configfs.h>
16#include <linux/configfs.h>
17
18static struct config_group *iio_devices_group;
19static const struct config_item_type iio_device_type_group_type;
20
21static const struct config_item_type iio_devices_group_type = {
22	.ct_owner = THIS_MODULE,
23};
24
25static LIST_HEAD(iio_device_types_list);
26static DEFINE_MUTEX(iio_device_types_lock);
27
28static
29struct iio_sw_device_type *__iio_find_sw_device_type(const char *name,
30						     unsigned int len)
31{
32	struct iio_sw_device_type *d = NULL, *iter;
33
34	list_for_each_entry(iter, &iio_device_types_list, list)
35		if (!strcmp(iter->name, name)) {
36			d = iter;
37			break;
38		}
39
40	return d;
41}
42
43int iio_register_sw_device_type(struct iio_sw_device_type *d)
44{
45	struct iio_sw_device_type *iter;
46	int ret = 0;
47
48	mutex_lock(&iio_device_types_lock);
49	iter = __iio_find_sw_device_type(d->name, strlen(d->name));
50	if (iter)
51		ret = -EBUSY;
52	else
53		list_add_tail(&d->list, &iio_device_types_list);
54	mutex_unlock(&iio_device_types_lock);
55
56	if (ret)
57		return ret;
58
59	d->group = configfs_register_default_group(iio_devices_group, d->name,
60						&iio_device_type_group_type);
61	if (IS_ERR(d->group))
62		ret = PTR_ERR(d->group);
63
64	return ret;
65}
66EXPORT_SYMBOL(iio_register_sw_device_type);
67
68void iio_unregister_sw_device_type(struct iio_sw_device_type *dt)
69{
70	struct iio_sw_device_type *iter;
71
72	mutex_lock(&iio_device_types_lock);
73	iter = __iio_find_sw_device_type(dt->name, strlen(dt->name));
74	if (iter)
75		list_del(&dt->list);
76	mutex_unlock(&iio_device_types_lock);
77
78	configfs_unregister_default_group(dt->group);
79}
80EXPORT_SYMBOL(iio_unregister_sw_device_type);
81
82static
83struct iio_sw_device_type *iio_get_sw_device_type(const char *name)
84{
85	struct iio_sw_device_type *dt;
86
87	mutex_lock(&iio_device_types_lock);
88	dt = __iio_find_sw_device_type(name, strlen(name));
89	if (dt && !try_module_get(dt->owner))
90		dt = NULL;
91	mutex_unlock(&iio_device_types_lock);
92
93	return dt;
94}
95
96struct iio_sw_device *iio_sw_device_create(const char *type, const char *name)
97{
98	struct iio_sw_device *d;
99	struct iio_sw_device_type *dt;
100
101	dt = iio_get_sw_device_type(type);
102	if (!dt) {
103		pr_err("Invalid device type: %s\n", type);
104		return ERR_PTR(-EINVAL);
105	}
106	d = dt->ops->probe(name);
107	if (IS_ERR(d))
108		goto out_module_put;
109
110	d->device_type = dt;
111
112	return d;
113out_module_put:
114	module_put(dt->owner);
115	return d;
116}
117EXPORT_SYMBOL(iio_sw_device_create);
118
119void iio_sw_device_destroy(struct iio_sw_device *d)
120{
121	struct iio_sw_device_type *dt = d->device_type;
122
123	dt->ops->remove(d);
124	module_put(dt->owner);
125}
126EXPORT_SYMBOL(iio_sw_device_destroy);
127
128static struct config_group *device_make_group(struct config_group *group,
129					      const char *name)
130{
131	struct iio_sw_device *d;
132
133	d = iio_sw_device_create(group->cg_item.ci_name, name);
134	if (IS_ERR(d))
135		return ERR_CAST(d);
136
137	config_item_set_name(&d->group.cg_item, "%s", name);
138
139	return &d->group;
140}
141
142static void device_drop_group(struct config_group *group,
143			      struct config_item *item)
144{
145	struct iio_sw_device *d = to_iio_sw_device(item);
146
147	iio_sw_device_destroy(d);
148	config_item_put(item);
149}
150
151static struct configfs_group_operations device_ops = {
152	.make_group	= &device_make_group,
153	.drop_item	= &device_drop_group,
154};
155
156static const struct config_item_type iio_device_type_group_type = {
157	.ct_group_ops = &device_ops,
158	.ct_owner       = THIS_MODULE,
159};
160
161static int __init iio_sw_device_init(void)
162{
163	iio_devices_group =
164		configfs_register_default_group(&iio_configfs_subsys.su_group,
165						"devices",
166						&iio_devices_group_type);
167	return PTR_ERR_OR_ZERO(iio_devices_group);
168}
169module_init(iio_sw_device_init);
170
171static void __exit iio_sw_device_exit(void)
172{
173	configfs_unregister_default_group(iio_devices_group);
174}
175module_exit(iio_sw_device_exit);
176
177MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>");
178MODULE_DESCRIPTION("Industrial I/O software devices support");
179MODULE_LICENSE("GPL v2");
180