1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * USB Type-C Connector Class Port Mapping Utility 4 * 5 * Copyright (C) 2021, Intel Corporation 6 * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com> 7 */ 8 9 #include <linux/acpi.h> 10 #include <linux/usb.h> 11 #include <linux/usb/typec.h> 12 13 #include "class.h" 14 15 struct port_node { 16 struct list_head list; 17 struct device *dev; 18 void *pld; 19 }; 20 21 static int acpi_pld_match(const struct acpi_pld_info *pld1, 22 const struct acpi_pld_info *pld2) 23 { 24 if (!pld1 || !pld2) 25 return 0; 26 27 /* 28 * To speed things up, first checking only the group_position. It seems 29 * to often have the first unique value in the _PLD. 30 */ 31 if (pld1->group_position == pld2->group_position) 32 return !memcmp(pld1, pld2, sizeof(struct acpi_pld_info)); 33 34 return 0; 35 } 36 37 void *get_pld(struct device *dev) 38 { 39 #ifdef CONFIG_ACPI 40 struct acpi_pld_info *pld; 41 acpi_status status; 42 43 if (!has_acpi_companion(dev)) 44 return NULL; 45 46 status = acpi_get_physical_device_location(ACPI_HANDLE(dev), &pld); 47 if (ACPI_FAILURE(status)) 48 return NULL; 49 50 return pld; 51 #else 52 return NULL; 53 #endif 54 } 55 56 void free_pld(void *pld) 57 { 58 #ifdef CONFIG_ACPI 59 ACPI_FREE(pld); 60 #endif 61 } 62 63 static int __link_port(struct typec_port *con, struct port_node *node) 64 { 65 int ret; 66 67 ret = sysfs_create_link(&node->dev->kobj, &con->dev.kobj, "connector"); 68 if (ret) 69 return ret; 70 71 ret = sysfs_create_link(&con->dev.kobj, &node->dev->kobj, 72 dev_name(node->dev)); 73 if (ret) { 74 sysfs_remove_link(&node->dev->kobj, "connector"); 75 return ret; 76 } 77 78 list_add_tail(&node->list, &con->port_list); 79 80 return 0; 81 } 82 83 static int link_port(struct typec_port *con, struct port_node *node) 84 { 85 int ret; 86 87 mutex_lock(&con->port_list_lock); 88 ret = __link_port(con, node); 89 mutex_unlock(&con->port_list_lock); 90 91 return ret; 92 } 93 94 static void __unlink_port(struct typec_port *con, struct port_node *node) 95 { 96 sysfs_remove_link(&con->dev.kobj, dev_name(node->dev)); 97 sysfs_remove_link(&node->dev->kobj, "connector"); 98 list_del(&node->list); 99 } 100 101 static void unlink_port(struct typec_port *con, struct port_node *node) 102 { 103 mutex_lock(&con->port_list_lock); 104 __unlink_port(con, node); 105 mutex_unlock(&con->port_list_lock); 106 } 107 108 static struct port_node *create_port_node(struct device *port) 109 { 110 struct port_node *node; 111 112 node = kzalloc(sizeof(*node), GFP_KERNEL); 113 if (!node) 114 return ERR_PTR(-ENOMEM); 115 116 node->dev = get_device(port); 117 node->pld = get_pld(port); 118 119 return node; 120 } 121 122 static void remove_port_node(struct port_node *node) 123 { 124 put_device(node->dev); 125 free_pld(node->pld); 126 kfree(node); 127 } 128 129 static int connector_match(struct device *dev, const void *data) 130 { 131 const struct port_node *node = data; 132 133 if (!is_typec_port(dev)) 134 return 0; 135 136 return acpi_pld_match(to_typec_port(dev)->pld, node->pld); 137 } 138 139 static struct device *find_connector(struct port_node *node) 140 { 141 if (!node->pld) 142 return NULL; 143 144 return class_find_device(&typec_class, NULL, node, connector_match); 145 } 146 147 /** 148 * typec_link_port - Link a port to its connector 149 * @port: The port device 150 * 151 * Find the connector of @port and create symlink named "connector" for it. 152 * Returns 0 on success, or errno in case of a failure. 153 * 154 * NOTE. The function increments the reference count of @port on success. 155 */ 156 int typec_link_port(struct device *port) 157 { 158 struct device *connector; 159 struct port_node *node; 160 int ret = 0; 161 162 node = create_port_node(port); 163 if (IS_ERR(node)) 164 return PTR_ERR(node); 165 166 connector = find_connector(node); 167 if (!connector) 168 goto remove_node; 169 170 ret = link_port(to_typec_port(connector), node); 171 if (ret) 172 goto put_connector; 173 174 return 0; 175 176 put_connector: 177 put_device(connector); 178 remove_node: 179 remove_port_node(node); 180 181 return ret; 182 } 183 EXPORT_SYMBOL_GPL(typec_link_port); 184 185 static int port_match_and_unlink(struct device *connector, void *port) 186 { 187 struct port_node *node; 188 struct port_node *tmp; 189 int ret = 0; 190 191 if (!is_typec_port(connector)) 192 return 0; 193 194 mutex_lock(&to_typec_port(connector)->port_list_lock); 195 list_for_each_entry_safe(node, tmp, &to_typec_port(connector)->port_list, list) { 196 ret = node->dev == port; 197 if (ret) { 198 unlink_port(to_typec_port(connector), node); 199 remove_port_node(node); 200 put_device(connector); 201 break; 202 } 203 } 204 mutex_unlock(&to_typec_port(connector)->port_list_lock); 205 206 return ret; 207 } 208 209 /** 210 * typec_unlink_port - Unlink port from its connector 211 * @port: The port device 212 * 213 * Removes the symlink "connector" and decrements the reference count of @port. 214 */ 215 void typec_unlink_port(struct device *port) 216 { 217 class_for_each_device(&typec_class, NULL, port, port_match_and_unlink); 218 } 219 EXPORT_SYMBOL_GPL(typec_unlink_port); 220