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");