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