drivers/usb/common/led.c

   1 /*
   2  * LED Triggers for USB Activity
   3  *
   4  * Copyright 2014 Michal Sojka <sojka@merica.cz>
   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
  12 #include <linux/module.h>
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/leds.h>
  16 #include <linux/usb.h>
  17
  18 #define BLINK_DELAY 30
  19
  20 static unsigned long usb_blink_delay = BLINK_DELAY;
  21
  22 DEFINE_LED_TRIGGER(ledtrig_usb_gadget);
  23 DEFINE_LED_TRIGGER(ledtrig_usb_host);
  24
  25 void usb_led_activity(enum usb_led_event ev)
  26 {
  27         struct led_trigger *trig = NULL;
  28
  29         switch (ev) {
  30         case USB_LED_EVENT_GADGET:
  31                 trig = ledtrig_usb_gadget;
  32                 break;
  33         case USB_LED_EVENT_HOST:
  34                 trig = ledtrig_usb_host;
  35                 break;
  36         }
  37         /* led_trigger_blink_oneshot() handles trig == NULL gracefully */
  38         led_trigger_blink_oneshot(trig, &usb_blink_delay, &usb_blink_delay, 0);
  39 }
  40 EXPORT_SYMBOL_GPL(usb_led_activity);
  41
  42
  43 static int __init ledtrig_usb_init(void)
  44 {
  45         led_trigger_register_simple("usb-gadget", &ledtrig_usb_gadget);
  46         led_trigger_register_simple("usb-host", &ledtrig_usb_host);
  47         return 0;
  48 }
  49
  50 static void __exit ledtrig_usb_exit(void)
  51 {
  52         led_trigger_unregister_simple(ledtrig_usb_gadget);
  53         led_trigger_unregister_simple(ledtrig_usb_host);
  54 }
  55
  56 module_init(ledtrig_usb_init);
  57 module_exit(ledtrig_usb_exit);