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 static const struct attribute_group ports_group = { 117 .name = "ports", 118 .attrs = ports_attrs, 119 }; 120 121 /*************************************** 122 * Adding & removing ports 123 ***************************************/ 124 125 /** 126 * usbport_trig_port_observed - Check if port should be observed 127 */ 128 static bool usbport_trig_port_observed(struct usbport_trig_data *usbport_data, 129 struct usb_device *usb_dev, int port1) 130 { 131 struct device *dev = usbport_data->led_cdev->dev; 132 struct device_node *led_np = dev->of_node; 133 struct of_phandle_args args; 134 struct device_node *port_np; 135 int count, i; 136 137 if (!led_np) 138 return false; 139 140 /* Get node of port being added */ 141 port_np = usb_of_get_child_node(usb_dev->dev.of_node, port1); 142 if (!port_np) 143 return false; 144 145 /* Amount of trigger sources for this LED */ 146 count = of_count_phandle_with_args(led_np, "trigger-sources", 147 "#trigger-source-cells"); 148 if (count < 0) { 149 dev_warn(dev, "Failed to get trigger sources for %pOF\n", 150 led_np); 151 return false; 152 } 153 154 /* Check list of sources for this specific port */ 155 for (i = 0; i < count; i++) { 156 int err; 157 158 err = of_parse_phandle_with_args(led_np, "trigger-sources", 159 "#trigger-source-cells", i, 160 &args); 161 if (err) { 162 dev_err(dev, "Failed to get trigger source phandle at index %d: %d\n", 163 i, err); 164 continue; 165 } 166 167 of_node_put(args.np); 168 169 if (args.np == port_np) 170 return true; 171 } 172 173 return false; 174 } 175 176 static int usbport_trig_add_port(struct usbport_trig_data *usbport_data, 177 struct usb_device *usb_dev, 178 const char *hub_name, int portnum) 179 { 180 struct led_classdev *led_cdev = usbport_data->led_cdev; 181 struct usbport_trig_port *port; 182 size_t len; 183 int err; 184 185 port = kzalloc(sizeof(*port), GFP_KERNEL); 186 if (!port) { 187 err = -ENOMEM; 188 goto err_out; 189 } 190 191 port->data = usbport_data; 192 port->hub = usb_dev; 193 port->portnum = portnum; 194 port->observed = usbport_trig_port_observed(usbport_data, usb_dev, 195 portnum); 196 197 len = strlen(hub_name) + 8; 198 port->port_name = kzalloc(len, GFP_KERNEL); 199 if (!port->port_name) { 200 err = -ENOMEM; 201 goto err_free_port; 202 } 203 snprintf(port->port_name, len, "%s-port%d", hub_name, portnum); 204 205 sysfs_attr_init(&port->attr.attr); 206 port->attr.attr.name = port->port_name; 207 port->attr.attr.mode = S_IRUSR | S_IWUSR; 208 port->attr.show = usbport_trig_port_show; 209 port->attr.store = usbport_trig_port_store; 210 211 err = sysfs_add_file_to_group(&led_cdev->dev->kobj, &port->attr.attr, 212 ports_group.name); 213 if (err) 214 goto err_free_port_name; 215 216 list_add_tail(&port->list, &usbport_data->ports); 217 218 return 0; 219 220 err_free_port_name: 221 kfree(port->port_name); 222 err_free_port: 223 kfree(port); 224 err_out: 225 return err; 226 } 227 228 static int usbport_trig_add_usb_dev_ports(struct usb_device *usb_dev, 229 void *data) 230 { 231 struct usbport_trig_data *usbport_data = data; 232 int i; 233 234 for (i = 1; i <= usb_dev->maxchild; i++) 235 usbport_trig_add_port(usbport_data, usb_dev, 236 dev_name(&usb_dev->dev), i); 237 238 return 0; 239 } 240 241 static void usbport_trig_remove_port(struct usbport_trig_data *usbport_data, 242 struct usbport_trig_port *port) 243 { 244 struct led_classdev *led_cdev = usbport_data->led_cdev; 245 246 list_del(&port->list); 247 sysfs_remove_file_from_group(&led_cdev->dev->kobj, &port->attr.attr, 248 ports_group.name); 249 kfree(port->port_name); 250 kfree(port); 251 } 252 253 static void usbport_trig_remove_usb_dev_ports(struct usbport_trig_data *usbport_data, 254 struct usb_device *usb_dev) 255 { 256 struct usbport_trig_port *port, *tmp; 257 258 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) { 259 if (port->hub == usb_dev) 260 usbport_trig_remove_port(usbport_data, port); 261 } 262 } 263 264 /*************************************** 265 * Init, exit, etc. 266 ***************************************/ 267 268 static int usbport_trig_notify(struct notifier_block *nb, unsigned long action, 269 void *data) 270 { 271 struct usbport_trig_data *usbport_data = 272 container_of(nb, struct usbport_trig_data, nb); 273 struct led_classdev *led_cdev = usbport_data->led_cdev; 274 struct usb_device *usb_dev = data; 275 bool observed; 276 277 observed = usbport_trig_usb_dev_observed(usbport_data, usb_dev); 278 279 switch (action) { 280 case USB_DEVICE_ADD: 281 usbport_trig_add_usb_dev_ports(usb_dev, usbport_data); 282 if (observed && usbport_data->count++ == 0) 283 led_set_brightness(led_cdev, LED_FULL); 284 return NOTIFY_OK; 285 case USB_DEVICE_REMOVE: 286 usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev); 287 if (observed && --usbport_data->count == 0) 288 led_set_brightness(led_cdev, LED_OFF); 289 return NOTIFY_OK; 290 } 291 292 return NOTIFY_DONE; 293 } 294 295 static void usbport_trig_activate(struct led_classdev *led_cdev) 296 { 297 struct usbport_trig_data *usbport_data; 298 int err; 299 300 usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL); 301 if (!usbport_data) 302 return; 303 usbport_data->led_cdev = led_cdev; 304 305 /* List of ports */ 306 INIT_LIST_HEAD(&usbport_data->ports); 307 err = sysfs_create_group(&led_cdev->dev->kobj, &ports_group); 308 if (err) 309 goto err_free; 310 usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports); 311 usbport_trig_update_count(usbport_data); 312 313 /* Notifications */ 314 usbport_data->nb.notifier_call = usbport_trig_notify, 315 led_cdev->trigger_data = usbport_data; 316 usb_register_notify(&usbport_data->nb); 317 318 led_cdev->activated = true; 319 return; 320 321 err_free: 322 kfree(usbport_data); 323 } 324 325 static void usbport_trig_deactivate(struct led_classdev *led_cdev) 326 { 327 struct usbport_trig_data *usbport_data = led_cdev->trigger_data; 328 struct usbport_trig_port *port, *tmp; 329 330 if (!led_cdev->activated) 331 return; 332 333 list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) { 334 usbport_trig_remove_port(usbport_data, port); 335 } 336 337 usb_unregister_notify(&usbport_data->nb); 338 339 sysfs_remove_group(&led_cdev->dev->kobj, &ports_group); 340 341 kfree(usbport_data); 342 343 led_cdev->activated = false; 344 } 345 346 static struct led_trigger usbport_led_trigger = { 347 .name = "usbport", 348 .activate = usbport_trig_activate, 349 .deactivate = usbport_trig_deactivate, 350 }; 351 352 static int __init usbport_trig_init(void) 353 { 354 return led_trigger_register(&usbport_led_trigger); 355 } 356 357 static void __exit usbport_trig_exit(void) 358 { 359 led_trigger_unregister(&usbport_led_trigger); 360 } 361 362 module_init(usbport_trig_init); 363 module_exit(usbport_trig_exit); 364 365 MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>"); 366 MODULE_DESCRIPTION("USB port trigger"); 367 MODULE_LICENSE("GPL v2"); 368