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