drivers/usb/core/ledtrig-usbport.c

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