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 18 static struct config_group *iio_triggers_group; 19 static const struct config_item_type iio_trigger_type_group_type; 20 21 static const struct config_item_type iio_triggers_group_type = { 22 .ct_owner = THIS_MODULE, 23 }; 24 25 static LIST_HEAD(iio_trigger_types_list); 26 static DEFINE_MUTEX(iio_trigger_types_lock); 27 28 static 29 struct 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 43 int 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 } 70 EXPORT_SYMBOL(iio_register_sw_trigger_type); 71 72 void 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 } 84 EXPORT_SYMBOL(iio_unregister_sw_trigger_type); 85 86 static 87 struct 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 } 99 100 struct 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; 117 out_module_put: 118 module_put(tt->owner); 119 return t; 120 } 121 EXPORT_SYMBOL(iio_sw_trigger_create); 122 123 void 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 } 130 EXPORT_SYMBOL(iio_sw_trigger_destroy); 131 132 static 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 } 145 146 static 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 } 154 155 static struct configfs_group_operations trigger_ops = { 156 .make_group = &trigger_make_group, 157 .drop_item = &trigger_drop_group, 158 }; 159 160 static const struct config_item_type iio_trigger_type_group_type = { 161 .ct_group_ops = &trigger_ops, 162 .ct_owner = THIS_MODULE, 163 }; 164 165 static 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 } 173 module_init(iio_sw_trigger_init); 174 175 static void __exit iio_sw_trigger_exit(void) 176 { 177 configfs_unregister_default_group(iio_triggers_group); 178 } 179 module_exit(iio_sw_trigger_exit); 180 181 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); 182 MODULE_DESCRIPTION("Industrial I/O software triggers support"); 183 MODULE_LICENSE("GPL v2"); 184