drivers/usb/common/led.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * LED Triggers for USB Activity
   4  *
   5  * Copyright 2014 Michal Sojka <sojka@merica.cz>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  */
  12
  13 #include <linux/module.h>
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/leds.h>
  17 #include <linux/usb.h>
  18
  19 #define BLINK_DELAY 30
  20
  21 static unsigned long usb_blink_delay = BLINK_DELAY;
  22
  23 DEFINE_LED_TRIGGER(ledtrig_usb_gadget);
  24 DEFINE_LED_TRIGGER(ledtrig_usb_host);
  25
  26 void usb_led_activity(enum usb_led_event ev)
  27 {
  28         struct led_trigger *trig = NULL;
  29
  30         switch (ev) {
  31         case USB_LED_EVENT_GADGET:
  32                 trig = ledtrig_usb_gadget;
  33                 break;
  34         case USB_LED_EVENT_HOST:
  35                 trig = ledtrig_usb_host;
  36                 break;
  37         }
  38         /* led_trigger_blink_oneshot() handles trig == NULL gracefully */
  39         led_trigger_blink_oneshot(trig, &usb_blink_delay, &usb_blink_delay, 0);
  40 }
  41 EXPORT_SYMBOL_GPL(usb_led_activity);
  42
  43
  44 static int __init ledtrig_usb_init(void)
  45 {
  46         led_trigger_register_simple("usb-gadget", &ledtrig_usb_gadget);
  47         led_trigger_register_simple("usb-host", &ledtrig_usb_host);
  48         return 0;
  49 }
  50
  51 static void __exit ledtrig_usb_exit(void)
  52 {
  53         led_trigger_unregister_simple(ledtrig_usb_gadget);
  54         led_trigger_unregister_simple(ledtrig_usb_host);
  55 }
  56
  57 module_init(ledtrig_usb_init);
  58 module_exit(ledtrig_usb_exit);