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