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 ret = PTR_ERR(t->group); 63 64 return ret; 65 } 66 EXPORT_SYMBOL(iio_register_sw_trigger_type); 67 68 void iio_unregister_sw_trigger_type(struct iio_sw_trigger_type *t) 69 { 70 struct iio_sw_trigger_type *iter; 71 72 mutex_lock(&iio_trigger_types_lock); 73 iter = __iio_find_sw_trigger_type(t->name, strlen(t->name)); 74 if (iter) 75 list_del(&t->list); 76 mutex_unlock(&iio_trigger_types_lock); 77 78 configfs_unregister_default_group(t->group); 79 } 80 EXPORT_SYMBOL(iio_unregister_sw_trigger_type); 81 82 static 83 struct iio_sw_trigger_type *iio_get_sw_trigger_type(const char *name) 84 { 85 struct iio_sw_trigger_type *t; 86 87 mutex_lock(&iio_trigger_types_lock); 88 t = __iio_find_sw_trigger_type(name, strlen(name)); 89 if (t && !try_module_get(t->owner)) 90 t = NULL; 91 mutex_unlock(&iio_trigger_types_lock); 92 93 return t; 94 } 95 96 struct iio_sw_trigger *iio_sw_trigger_create(const char *type, const char *name) 97 { 98 struct iio_sw_trigger *t; 99 struct iio_sw_trigger_type *tt; 100 101 tt = iio_get_sw_trigger_type(type); 102 if (!tt) { 103 pr_err("Invalid trigger type: %s\n", type); 104 return ERR_PTR(-EINVAL); 105 } 106 t = tt->ops->probe(name); 107 if (IS_ERR(t)) 108 goto out_module_put; 109 110 t->trigger_type = tt; 111 112 return t; 113 out_module_put: 114 module_put(tt->owner); 115 return t; 116 } 117 EXPORT_SYMBOL(iio_sw_trigger_create); 118 119 void iio_sw_trigger_destroy(struct iio_sw_trigger *t) 120 { 121 struct iio_sw_trigger_type *tt = t->trigger_type; 122 123 tt->ops->remove(t); 124 module_put(tt->owner); 125 } 126 EXPORT_SYMBOL(iio_sw_trigger_destroy); 127 128 static struct config_group *trigger_make_group(struct config_group *group, 129 const char *name) 130 { 131 struct iio_sw_trigger *t; 132 133 t = iio_sw_trigger_create(group->cg_item.ci_name, name); 134 if (IS_ERR(t)) 135 return ERR_CAST(t); 136 137 config_item_set_name(&t->group.cg_item, "%s", name); 138 139 return &t->group; 140 } 141 142 static void trigger_drop_group(struct config_group *group, 143 struct config_item *item) 144 { 145 struct iio_sw_trigger *t = to_iio_sw_trigger(item); 146 147 iio_sw_trigger_destroy(t); 148 config_item_put(item); 149 } 150 151 static struct configfs_group_operations trigger_ops = { 152 .make_group = &trigger_make_group, 153 .drop_item = &trigger_drop_group, 154 }; 155 156 static const struct config_item_type iio_trigger_type_group_type = { 157 .ct_group_ops = &trigger_ops, 158 .ct_owner = THIS_MODULE, 159 }; 160 161 static int __init iio_sw_trigger_init(void) 162 { 163 iio_triggers_group = 164 configfs_register_default_group(&iio_configfs_subsys.su_group, 165 "triggers", 166 &iio_triggers_group_type); 167 return PTR_ERR_OR_ZERO(iio_triggers_group); 168 } 169 module_init(iio_sw_trigger_init); 170 171 static void __exit iio_sw_trigger_exit(void) 172 { 173 configfs_unregister_default_group(iio_triggers_group); 174 } 175 module_exit(iio_sw_trigger_exit); 176 177 MODULE_AUTHOR("Daniel Baluta <daniel.baluta@intel.com>"); 178 MODULE_DESCRIPTION("Industrial I/O software triggers support"); 179 MODULE_LICENSE("GPL v2"); 180