1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * USB port LED trigger 4 * 5 * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl> 6 */ 7 8 #include <linux/device.h> 9 #include <linux/leds.h> 10 #include <linux/module.h> 11 #include <linux/of.h> 12 #include <linux/slab.h> 13 #include <linux/usb.h> 14 #include <linux/usb/of.h> 15 16 struct usbport_trig_data { 17 struct led_classdev *led_cdev; 18 struct list_head ports; 19 struct notifier_block nb; 20 int count; /* Amount of connected matching devices */ 21 }; 22 23 struct usbport_trig_port { 24 struct usbport_trig_data *data; 25 struct usb_device *hub; 26 int portnum; 27 char *port_name; 28 bool observed; 29 struct device_attribute attr; 30 struct list_head list; 31 }; 32 33 /*************************************** 34 * Helpers 35 ***************************************/ 36 37 /** 38 * usbport_trig_usb_dev_observed - Check if dev is connected to observed port 39 */ 40 static bool usbport_trig_usb_dev_observed(struct usbport_trig_data *usbport_data, 41 struct usb_device *usb_dev) 42 { 43 struct usbport_trig_port *port; 44 45 if (!usb_dev->parent) 46 return false; 47 48 list_for_each_entry(port, &usbport_data->ports, list) { 49 if (usb_dev->parent == port->hub && 50 usb_dev->portnum == port->portnum) 51 return port->observed; 52 } 53 54 return false; 55 } 56 57 static int usbport_trig_usb_dev_check(struct usb_device *usb_dev, void *data) 58 { 59 struct usbport_trig_data *usbport_data = data; 60 61 if (usbport_trig_usb_dev_observed(usbport_data, usb_dev)) 62 usbport_data->count++; 63 64 return 0; 65 } 66 67 /** 68 * usbport_trig_update_count - Recalculate amount of connected matching devices 69 */ 70 static void usbport_trig_update_count(struct usbport_trig_data *usbport_data) 71 { 72 struct led_classdev *led_cdev = usbport_data->led_cdev; 73 74 usbport_data->count = 0; 75 usb_for_each_dev(usbport_data, usbport_trig_usb_dev_check); 76 led_set_brightness(led_cdev, usbport_data->count ? LED_FULL : LED_OFF); 77 } 78 79 /*************************************** 80 * Device attr 81 ***************************************/ 82 83 static ssize_t usbport_trig_port_show(struct device *dev, 84 struct device_attribute *attr, char *buf) 85 { 86 struct usbport_trig_port *port = container_of(attr, 87 struct usbport_trig_port, 88 attr); 89 90 return sprintf(buf, "%d\n", port->observed) + 1; 91 } 92 93 static ssize_t usbport_trig_port_store(struct device *dev, 94 struct device_attribute *attr, 95 const char *buf, size_t size) 96 { 97 struct usbport_trig_port *port = container_of(attr, 98 struct usbport_trig_port, 99 attr); 100 101 if (!strcmp(buf, "0") || !strcmp(buf, "0\n")) 102 port->observed = 0; 103 else if (!strcmp(buf, "1") || !strcmp(buf, "1\n")) 104 port->observed = 1; 105 else 106 return -EINVAL; 107 108 usbport_trig_update_count(port->data); 109 110 return size; 111 } 112 113 static struct attribute *ports_attrs[] = { 114 NULL, 115 }; 116 117 static const struct attribute_group ports_group = { 118 .name = "ports", 119 .attrs = ports_attrs, 120 }; 121 122 static const struct attribute_group *ports_groups[] = { 123 &ports_group, 124 NULL 125 }; 126 127 /*************************************** 128 * Adding & removing ports 129 ***************************************/ 130 131 /** 132 * usbport_trig_port_observed - Check if port should be observed 133 */ 134 static bool usbport_trig_port_observed(struct usbport_trig_data *usbport_data, 135 struct usb_device *usb_dev, int port1) 136 { 137 struct device *dev = usbport_data->led_cdev->dev; 138 struct device_node *led_np = dev->of_node; 139 struct of_phandle_args args; 140 struct device_node *port_np; 141 int count, i; 142 143 if (!led_np) 144 return false; 145 146 /* 147 * Get node of port being added 148 * 149 * FIXME: This is really the device node of the connected device 150 */ 151 port_np = usb_of_get_device_node(usb_dev, port1); 152 if (!port_np) 153 return false; 154 155 of_node_put(port_np); 156 157 /* Amount of trigger sources for this LED */ 158 count = of_count_phandle_with_args(led_np, "trigger-sources", 159 "#trigger-source-cells"); 160 if (count < 0) { 161 dev_warn(dev, "Failed to get trigger sources for %pOF\n", 162 led_np); 163 return false; 164 } 165 166 /* Check list of sources for this specific port */ 167 for (i = 0; i < count; i++) { 168 int err; 169 170 err = of_parse_phandle_with_args(led_np, "trigger-sources", 171 "#trigger-source-cells", i, 172 &args); 173 if (err) { 174 dev_err(dev, "Failed to get trigger source phandle at index %d: %d\n", 175 i, err); 176 continue; 177 } 178 179 of_node_put(args.np); 180 181 if (args.np == port_np) 182 return true; 183 } 184 185 return false; 186 } 187 188 static int usbport_trig_add_port(struct usbport_trig_data *usbport_data, 189 struct usb_device *usb_dev, 190 const char *hub_name, int portnum) 191 { 192 struct led_classdev *led_cdev = usbport_data->led_cdev; 193 struct usbport_trig_port *port; 194 size_t len; 195 int err; 196 197 port = kzalloc(sizeof(*port), GFP_KERNEL); 198 if (!port) { 199 err = -ENOMEM; 200 goto err_out; 201 } 202 203 port->data = usbport_data; 204 port->hub = usb_dev; 205 port->portnum = portnum; 206 port->observed = usbport_trig_port_observed(usbport_data, usb_dev, 207 portnum); 208 209 len = strlen(hub_name) + 8; 210 port->port_name = kzalloc(len, GFP_KERNEL); 211 if (!port->port_name) { 212 err = -ENOMEM; 213 goto err_free_port; 214 } 215 snprintf(port->port_name, len, "%s-port%d", hub_name, portnum); 216 217 sysfs_attr_init(&port->attr.attr); 218 port->attr.attr.name = port->port_name; 219 port->attr.attr.mode = S_IRUSR | S_IWUSR; 220 port->attr.show = usbport_trig_port_show; 221 port->attr.store = usbport_trig_port_store; 222 223 err = sysfs_add_file_to_group(&led_cdev->dev->kobj, &port->attr.attr, 224 ports_group.name); 225 if (err) 226 goto err_free_port_name; 227 228 list_add_tail(&port->list, &usbport_data->ports); 229 230 return 0; 231 232 err_free_port_name: 233 kfree(port->port_name); 234 err_free_port: 235 kfree(port); 236 err_out: 237 return err; 238 } 239 240 static int usbport_trig_add_usb_dev_ports(struct usb_device *usb_dev, 241 void *data) 242 { 243 struct usbport_trig_data *usbport_data = data; 244 int i; 245 246 for (i = 1; i <= usb_dev->maxchild; i++) 247 usbport_trig_add_port(usbport_data, usb_dev, 248 dev_name(&usb_dev->dev), i); 249 250 return 0; 251 } 252 253 static void usbport_trig_remove_port(struct usbport_trig_data *usbport_data, 254 struct usbport_trig_port *port) 255 { 256 struct led_classdev *led_cdev = usbport_data->led_cdev; 257 258 list_del(&port->list); 259 sysfs_remove_file_from_group(&led_cdev->dev->kobj, &port->attr.attr, 260 ports_group.name); 261 kfree(port->port_name); 262 kfree(port); 263 } 264 265 static void usbport_trig_remove_usb_dev_ports(struct usbport_trig_data *usbport_data, 266 struct usb_device *usb_dev) 267 { 268 struct usbport_trig_port *port, *tmp; 269 270 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) { 271 if (port->hub == usb_dev) 272 usbport_trig_remove_port(usbport_data, port); 273 } 274 } 275 276 /*************************************** 277 * Init, exit, etc. 278 ***************************************/ 279 280 static int usbport_trig_notify(struct notifier_block *nb, unsigned long action, 281 void *data) 282 { 283 struct usbport_trig_data *usbport_data = 284 container_of(nb, struct usbport_trig_data, nb); 285 struct led_classdev *led_cdev = usbport_data->led_cdev; 286 struct usb_device *usb_dev = data; 287 bool observed; 288 289 observed = usbport_trig_usb_dev_observed(usbport_data, usb_dev); 290 291 switch (action) { 292 case USB_DEVICE_ADD: 293 usbport_trig_add_usb_dev_ports(usb_dev, usbport_data); 294 if (observed && usbport_data->count++ == 0) 295 led_set_brightness(led_cdev, LED_FULL); 296 return NOTIFY_OK; 297 case USB_DEVICE_REMOVE: 298 usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev); 299 if (observed && --usbport_data->count == 0) 300 led_set_brightness(led_cdev, LED_OFF); 301 return NOTIFY_OK; 302 } 303 304 return NOTIFY_DONE; 305 } 306 307 static int usbport_trig_activate(struct led_classdev *led_cdev) 308 { 309 struct usbport_trig_data *usbport_data; 310 311 usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL); 312 if (!usbport_data) 313 return -ENOMEM; 314 usbport_data->led_cdev = led_cdev; 315 316 /* List of ports */ 317 INIT_LIST_HEAD(&usbport_data->ports); 318 usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports); 319 usbport_trig_update_count(usbport_data); 320 321 /* Notifications */ 322 usbport_data->nb.notifier_call = usbport_trig_notify; 323 led_set_trigger_data(led_cdev, usbport_data); 324 usb_register_notify(&usbport_data->nb); 325 326 return 0; 327 } 328 329 static void usbport_trig_deactivate(struct led_classdev *led_cdev) 330 { 331 struct usbport_trig_data *usbport_data = led_get_trigger_data(led_cdev); 332 struct usbport_trig_port *port, *tmp; 333 334 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) { 335 usbport_trig_remove_port(usbport_data, port); 336 } 337 338 usb_unregister_notify(&usbport_data->nb); 339 340 kfree(usbport_data); 341 } 342 343 static struct led_trigger usbport_led_trigger = { 344 .name = "usbport", 345 .activate = usbport_trig_activate, 346 .deactivate = usbport_trig_deactivate, 347 .groups = ports_groups, 348 }; 349 350 static int __init usbport_trig_init(void) 351 { 352 return led_trigger_register(&usbport_led_trigger); 353 } 354 355 static void __exit usbport_trig_exit(void) 356 { 357 led_trigger_unregister(&usbport_led_trigger); 358 } 359 360 module_init(usbport_trig_init); 361 module_exit(usbport_trig_exit); 362 363 MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>"); 364 MODULE_DESCRIPTION("USB port trigger"); 365 MODULE_LICENSE("GPL v2"); 366