1 /* 2 * USB port LED trigger 3 * 4 * Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11 #include <linux/device.h> 12 #include <linux/leds.h> 13 #include <linux/module.h> 14 #include <linux/of.h> 15 #include <linux/slab.h> 16 #include <linux/usb.h> 17 #include <linux/usb/of.h> 18 19 struct usbport_trig_data { 20 struct led_classdev *led_cdev; 21 struct list_head ports; 22 struct notifier_block nb; 23 int count; /* Amount of connected matching devices */ 24 }; 25 26 struct usbport_trig_port { 27 struct usbport_trig_data *data; 28 struct usb_device *hub; 29 int portnum; 30 char *port_name; 31 bool observed; 32 struct device_attribute attr; 33 struct list_head list; 34 }; 35 36 /*************************************** 37 * Helpers 38 ***************************************/ 39 40 /** 41 * usbport_trig_usb_dev_observed - Check if dev is connected to observed port 42 */ 43 static bool usbport_trig_usb_dev_observed(struct usbport_trig_data *usbport_data, 44 struct usb_device *usb_dev) 45 { 46 struct usbport_trig_port *port; 47 48 if (!usb_dev->parent) 49 return false; 50 51 list_for_each_entry(port, &usbport_data->ports, list) { 52 if (usb_dev->parent == port->hub && 53 usb_dev->portnum == port->portnum) 54 return port->observed; 55 } 56 57 return false; 58 } 59 60 static int usbport_trig_usb_dev_check(struct usb_device *usb_dev, void *data) 61 { 62 struct usbport_trig_data *usbport_data = data; 63 64 if (usbport_trig_usb_dev_observed(usbport_data, usb_dev)) 65 usbport_data->count++; 66 67 return 0; 68 } 69 70 /** 71 * usbport_trig_update_count - Recalculate amount of connected matching devices 72 */ 73 static void usbport_trig_update_count(struct usbport_trig_data *usbport_data) 74 { 75 struct led_classdev *led_cdev = usbport_data->led_cdev; 76 77 usbport_data->count = 0; 78 usb_for_each_dev(usbport_data, usbport_trig_usb_dev_check); 79 led_set_brightness(led_cdev, usbport_data->count ? LED_FULL : LED_OFF); 80 } 81 82 /*************************************** 83 * Device attr 84 ***************************************/ 85 86 static ssize_t usbport_trig_port_show(struct device *dev, 87 struct device_attribute *attr, char *buf) 88 { 89 struct usbport_trig_port *port = container_of(attr, 90 struct usbport_trig_port, 91 attr); 92 93 return sprintf(buf, "%d\n", port->observed) + 1; 94 } 95 96 static ssize_t usbport_trig_port_store(struct device *dev, 97 struct device_attribute *attr, 98 const char *buf, size_t size) 99 { 100 struct usbport_trig_port *port = container_of(attr, 101 struct usbport_trig_port, 102 attr); 103 104 if (!strcmp(buf, "0") || !strcmp(buf, "0\n")) 105 port->observed = 0; 106 else if (!strcmp(buf, "1") || !strcmp(buf, "1\n")) 107 port->observed = 1; 108 else 109 return -EINVAL; 110 111 usbport_trig_update_count(port->data); 112 113 return size; 114 } 115 116 static struct attribute *ports_attrs[] = { 117 NULL, 118 }; 119 static const struct attribute_group ports_group = { 120 .name = "ports", 121 .attrs = ports_attrs, 122 }; 123 124 /*************************************** 125 * Adding & removing ports 126 ***************************************/ 127 128 /** 129 * usbport_trig_port_observed - Check if port should be observed 130 */ 131 static bool usbport_trig_port_observed(struct usbport_trig_data *usbport_data, 132 struct usb_device *usb_dev, int port1) 133 { 134 struct device *dev = usbport_data->led_cdev->dev; 135 struct device_node *led_np = dev->of_node; 136 struct of_phandle_args args; 137 struct device_node *port_np; 138 int count, i; 139 140 if (!led_np) 141 return false; 142 143 /* Get node of port being added */ 144 port_np = usb_of_get_child_node(usb_dev->dev.of_node, port1); 145 if (!port_np) 146 return false; 147 148 /* Amount of trigger sources for this LED */ 149 count = of_count_phandle_with_args(led_np, "trigger-sources", 150 "#trigger-source-cells"); 151 if (count < 0) { 152 dev_warn(dev, "Failed to get trigger sources for %s\n", 153 led_np->full_name); 154 return false; 155 } 156 157 /* Check list of sources for this specific port */ 158 for (i = 0; i < count; i++) { 159 int err; 160 161 err = of_parse_phandle_with_args(led_np, "trigger-sources", 162 "#trigger-source-cells", i, 163 &args); 164 if (err) { 165 dev_err(dev, "Failed to get trigger source phandle at index %d: %d\n", 166 i, err); 167 continue; 168 } 169 170 of_node_put(args.np); 171 172 if (args.np == port_np) 173 return true; 174 } 175 176 return false; 177 } 178 179 static int usbport_trig_add_port(struct usbport_trig_data *usbport_data, 180 struct usb_device *usb_dev, 181 const char *hub_name, int portnum) 182 { 183 struct led_classdev *led_cdev = usbport_data->led_cdev; 184 struct usbport_trig_port *port; 185 size_t len; 186 int err; 187 188 port = kzalloc(sizeof(*port), GFP_KERNEL); 189 if (!port) { 190 err = -ENOMEM; 191 goto err_out; 192 } 193 194 port->data = usbport_data; 195 port->hub = usb_dev; 196 port->portnum = portnum; 197 port->observed = usbport_trig_port_observed(usbport_data, usb_dev, 198 portnum); 199 200 len = strlen(hub_name) + 8; 201 port->port_name = kzalloc(len, GFP_KERNEL); 202 if (!port->port_name) { 203 err = -ENOMEM; 204 goto err_free_port; 205 } 206 snprintf(port->port_name, len, "%s-port%d", hub_name, portnum); 207 208 port->attr.attr.name = port->port_name; 209 port->attr.attr.mode = S_IRUSR | S_IWUSR; 210 port->attr.show = usbport_trig_port_show; 211 port->attr.store = usbport_trig_port_store; 212 213 err = sysfs_add_file_to_group(&led_cdev->dev->kobj, &port->attr.attr, 214 ports_group.name); 215 if (err) 216 goto err_free_port_name; 217 218 list_add_tail(&port->list, &usbport_data->ports); 219 220 return 0; 221 222 err_free_port_name: 223 kfree(port->port_name); 224 err_free_port: 225 kfree(port); 226 err_out: 227 return err; 228 } 229 230 static int usbport_trig_add_usb_dev_ports(struct usb_device *usb_dev, 231 void *data) 232 { 233 struct usbport_trig_data *usbport_data = data; 234 int i; 235 236 for (i = 1; i <= usb_dev->maxchild; i++) 237 usbport_trig_add_port(usbport_data, usb_dev, 238 dev_name(&usb_dev->dev), i); 239 240 return 0; 241 } 242 243 static void usbport_trig_remove_port(struct usbport_trig_data *usbport_data, 244 struct usbport_trig_port *port) 245 { 246 struct led_classdev *led_cdev = usbport_data->led_cdev; 247 248 list_del(&port->list); 249 sysfs_remove_file_from_group(&led_cdev->dev->kobj, &port->attr.attr, 250 ports_group.name); 251 kfree(port->port_name); 252 kfree(port); 253 } 254 255 static void usbport_trig_remove_usb_dev_ports(struct usbport_trig_data *usbport_data, 256 struct usb_device *usb_dev) 257 { 258 struct usbport_trig_port *port, *tmp; 259 260 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) { 261 if (port->hub == usb_dev) 262 usbport_trig_remove_port(usbport_data, port); 263 } 264 } 265 266 /*************************************** 267 * Init, exit, etc. 268 ***************************************/ 269 270 static int usbport_trig_notify(struct notifier_block *nb, unsigned long action, 271 void *data) 272 { 273 struct usbport_trig_data *usbport_data = 274 container_of(nb, struct usbport_trig_data, nb); 275 struct led_classdev *led_cdev = usbport_data->led_cdev; 276 struct usb_device *usb_dev = data; 277 bool observed; 278 279 observed = usbport_trig_usb_dev_observed(usbport_data, usb_dev); 280 281 switch (action) { 282 case USB_DEVICE_ADD: 283 usbport_trig_add_usb_dev_ports(usb_dev, usbport_data); 284 if (observed && usbport_data->count++ == 0) 285 led_set_brightness(led_cdev, LED_FULL); 286 return NOTIFY_OK; 287 case USB_DEVICE_REMOVE: 288 usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev); 289 if (observed && --usbport_data->count == 0) 290 led_set_brightness(led_cdev, LED_OFF); 291 return NOTIFY_OK; 292 } 293 294 return NOTIFY_DONE; 295 } 296 297 static void usbport_trig_activate(struct led_classdev *led_cdev) 298 { 299 struct usbport_trig_data *usbport_data; 300 int err; 301 302 usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL); 303 if (!usbport_data) 304 return; 305 usbport_data->led_cdev = led_cdev; 306 307 /* List of ports */ 308 INIT_LIST_HEAD(&usbport_data->ports); 309 err = sysfs_create_group(&led_cdev->dev->kobj, &ports_group); 310 if (err) 311 goto err_free; 312 usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports); 313 usbport_trig_update_count(usbport_data); 314 315 /* Notifications */ 316 usbport_data->nb.notifier_call = usbport_trig_notify, 317 led_cdev->trigger_data = usbport_data; 318 usb_register_notify(&usbport_data->nb); 319 320 led_cdev->activated = true; 321 return; 322 323 err_free: 324 kfree(usbport_data); 325 } 326 327 static void usbport_trig_deactivate(struct led_classdev *led_cdev) 328 { 329 struct usbport_trig_data *usbport_data = led_cdev->trigger_data; 330 struct usbport_trig_port *port, *tmp; 331 332 if (!led_cdev->activated) 333 return; 334 335 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) { 336 usbport_trig_remove_port(usbport_data, port); 337 } 338 339 usb_unregister_notify(&usbport_data->nb); 340 341 sysfs_remove_group(&led_cdev->dev->kobj, &ports_group); 342 343 kfree(usbport_data); 344 345 led_cdev->activated = false; 346 } 347 348 static struct led_trigger usbport_led_trigger = { 349 .name = "usbport", 350 .activate = usbport_trig_activate, 351 .deactivate = usbport_trig_deactivate, 352 }; 353 354 static int __init usbport_trig_init(void) 355 { 356 return led_trigger_register(&usbport_led_trigger); 357 } 358 359 static void __exit usbport_trig_exit(void) 360 { 361 led_trigger_unregister(&usbport_led_trigger); 362 } 363 364 module_init(usbport_trig_init); 365 module_exit(usbport_trig_exit); 366 367 MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>"); 368 MODULE_DESCRIPTION("USB port trigger"); 369 MODULE_LICENSE("GPL v2"); 370