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 18 static struct config_group *iio_devices_group; 19 static const struct config_item_type iio_device_type_group_type; 20 21 static const struct config_item_type iio_devices_group_type = { 22 .ct_owner = THIS_MODULE, 23 }; 24 25 static LIST_HEAD(iio_device_types_list); 26 static DEFINE_MUTEX(iio_device_types_lock); 27 28 static 29 struct 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 43 int 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 } 66 EXPORT_SYMBOL(iio_register_sw_device_type); 67 68 void 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 } 80 EXPORT_SYMBOL(iio_unregister_sw_device_type); 81 82 static 83 struct 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 96 struct 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; 113 out_module_put: 114 module_put(dt->owner); 115 return d; 116 } 117 EXPORT_SYMBOL(iio_sw_device_create); 118 119 void 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 } 126 EXPORT_SYMBOL(iio_sw_device_destroy); 127 128 static 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 } 141 142 static 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 } 150 151 static struct configfs_group_operations device_ops = { 152 .make_group = &device_make_group, 153 .drop_item = &device_drop_group, 154 }; 155 156 static const struct config_item_type iio_device_type_group_type = { 157 .ct_group_ops = &device_ops, 158 .ct_owner = THIS_MODULE, 159 }; 160 161 static 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 } 169 module_init(iio_sw_device_init); 170 171 static void __exit iio_sw_device_exit(void) 172 { 173 configfs_unregister_default_group(iio_devices_group); 174 } 175 module_exit(iio_sw_device_exit); 176 177 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); 178 MODULE_DESCRIPTION("Industrial I/O software devices support"); 179 MODULE_LICENSE("GPL v2"); 180