2 * LED USB device Trigger
4 * Toggles the LED to reflect the presence and activity of an USB device
5 * Copyright (C) Gabor Juhos <juhosg@openwrt.org>
7 * derived from ledtrig-netdev.c:
8 * Copyright 2007 Oliver Jowett <oliver@opencloud.com>
10 * ledtrig-netdev.c derived from ledtrig-timer.c:
11 * Copyright 2005-2006 Openedhand Ltd.
12 * Author: Richard Purdie <rpurdie@openedhand.com>
14 * This program is free software; you can redistribute it and/or modify
15 * it under the terms of the GNU General Public License version 2 as
16 * published by the Free Software Foundation.
20 #include <linux/module.h>
21 #include <linux/jiffies.h>
22 #include <linux/kernel.h>
23 #include <linux/init.h>
24 #include <linux/list.h>
25 #include <linux/spinlock.h>
26 #include <linux/device.h>
27 #include <linux/sysdev.h>
28 #include <linux/timer.h>
29 #include <linux/ctype.h>
30 #include <linux/slab.h>
31 #include <linux/leds.h>
32 #include <linux/usb.h>
36 #define DEV_BUS_ID_SIZE 32
39 * Configurable sysfs attributes:
41 * device_name - name of the USB device to monitor
42 * activity_interval - duration of LED blink, in milliseconds
45 struct usbdev_trig_data {
48 struct timer_list timer;
49 struct notifier_block notifier;
51 struct led_classdev *led_cdev;
52 struct usb_device *usb_dev;
54 char device_name[DEV_BUS_ID_SIZE];
59 static void usbdev_trig_update_state(struct usbdev_trig_data *td)
62 led_set_brightness(td->led_cdev, LED_FULL);
64 led_set_brightness(td->led_cdev, LED_OFF);
66 if (td->interval && td->usb_dev)
67 mod_timer(&td->timer, jiffies + td->interval);
69 del_timer(&td->timer);
72 static ssize_t usbdev_trig_name_show(struct device *dev,
73 struct device_attribute *attr,
76 struct led_classdev *led_cdev = dev_get_drvdata(dev);
77 struct usbdev_trig_data *td = led_cdev->trigger_data;
80 sprintf(buf, "%s\n", td->device_name);
81 read_unlock(&td->lock);
83 return strlen(buf) + 1;
86 static ssize_t usbdev_trig_name_store(struct device *dev,
87 struct device_attribute *attr,
91 struct led_classdev *led_cdev = dev_get_drvdata(dev);
92 struct usbdev_trig_data *td = led_cdev->trigger_data;
94 if (size < 0 || size >= DEV_BUS_ID_SIZE)
97 write_lock(&td->lock);
99 strcpy(td->device_name, buf);
100 if (size > 0 && td->device_name[size - 1] == '\n')
101 td->device_name[size - 1] = 0;
103 if (td->device_name[0] != 0) {
104 struct usb_device *usb_dev;
106 /* check for existing device to update from */
107 usb_dev = usb_find_device_by_name(td->device_name);
110 usb_put_dev(td->usb_dev);
112 td->usb_dev = usb_dev;
113 td->last_urbnum = atomic_read(&usb_dev->urbnum);
116 /* updates LEDs, may start timers */
117 usbdev_trig_update_state(td);
120 write_unlock(&td->lock);
124 static DEVICE_ATTR(device_name, 0644, usbdev_trig_name_show,
125 usbdev_trig_name_store);
127 static ssize_t usbdev_trig_interval_show(struct device *dev,
128 struct device_attribute *attr,
131 struct led_classdev *led_cdev = dev_get_drvdata(dev);
132 struct usbdev_trig_data *td = led_cdev->trigger_data;
134 read_lock(&td->lock);
135 sprintf(buf, "%u\n", jiffies_to_msecs(td->interval));
136 read_unlock(&td->lock);
138 return strlen(buf) + 1;
141 static ssize_t usbdev_trig_interval_store(struct device *dev,
142 struct device_attribute *attr,
146 struct led_classdev *led_cdev = dev_get_drvdata(dev);
147 struct usbdev_trig_data *td = led_cdev->trigger_data;
150 unsigned long value = simple_strtoul(buf, &after, 10);
151 size_t count = after - buf;
153 if (*after && isspace(*after))
156 if (count == size && value <= 10000) {
157 write_lock(&td->lock);
158 td->interval = msecs_to_jiffies(value);
159 usbdev_trig_update_state(td); /* resets timer */
160 write_unlock(&td->lock);
167 static DEVICE_ATTR(activity_interval, 0644, usbdev_trig_interval_show,
168 usbdev_trig_interval_store);
170 static int usbdev_trig_notify(struct notifier_block *nb,
174 struct usb_device *usb_dev;
175 struct usbdev_trig_data *td;
177 if (evt != USB_DEVICE_ADD && evt != USB_DEVICE_REMOVE)
181 td = container_of(nb, struct usbdev_trig_data, notifier);
183 write_lock(&td->lock);
185 if (strcmp(dev_name(&usb_dev->dev), td->device_name))
188 if (evt == USB_DEVICE_ADD) {
189 usb_get_dev(usb_dev);
190 if (td->usb_dev != NULL)
191 usb_put_dev(td->usb_dev);
192 td->usb_dev = usb_dev;
193 td->last_urbnum = atomic_read(&usb_dev->urbnum);
194 } else if (evt == USB_DEVICE_REMOVE) {
195 if (td->usb_dev != NULL) {
196 usb_put_dev(td->usb_dev);
201 usbdev_trig_update_state(td);
204 write_unlock(&td->lock);
208 /* here's the real work! */
209 static void usbdev_trig_timer(unsigned long arg)
211 struct usbdev_trig_data *td = (struct usbdev_trig_data *)arg;
214 write_lock(&td->lock);
216 if (!td->usb_dev || td->interval == 0) {
218 * we don't need to do timer work, just reflect device presence
221 led_set_brightness(td->led_cdev, LED_FULL);
223 led_set_brightness(td->led_cdev, LED_OFF);
229 new_urbnum = atomic_read(&td->usb_dev->urbnum);
235 * Base state is ON (device is present). If there's no device,
236 * we don't get this far and the LED is off.
238 * ON -> OFF on activity
240 if (td->led_cdev->brightness == LED_OFF)
241 led_set_brightness(td->led_cdev, LED_FULL);
242 else if (td->last_urbnum != new_urbnum)
243 led_set_brightness(td->led_cdev, LED_OFF);
248 * OFF -> ON on activity
250 if (td->led_cdev->brightness == LED_FULL)
251 led_set_brightness(td->led_cdev, LED_OFF);
252 else if (td->last_urbnum != new_urbnum)
253 led_set_brightness(td->led_cdev, LED_FULL);
256 td->last_urbnum = new_urbnum;
257 mod_timer(&td->timer, jiffies + td->interval);
260 write_unlock(&td->lock);
263 static void usbdev_trig_activate(struct led_classdev *led_cdev)
265 struct usbdev_trig_data *td;
268 td = kzalloc(sizeof(struct usbdev_trig_data), GFP_KERNEL);
272 rwlock_init(&td->lock);
274 td->notifier.notifier_call = usbdev_trig_notify;
275 td->notifier.priority = 10;
277 setup_timer(&td->timer, usbdev_trig_timer, (unsigned long) td);
279 td->led_cdev = led_cdev;
280 td->interval = msecs_to_jiffies(50);
282 led_cdev->trigger_data = td;
284 rc = device_create_file(led_cdev->dev, &dev_attr_device_name);
288 rc = device_create_file(led_cdev->dev, &dev_attr_activity_interval);
290 goto err_out_device_name;
292 usb_register_notify(&td->notifier);
296 device_remove_file(led_cdev->dev, &dev_attr_device_name);
298 led_cdev->trigger_data = NULL;
302 static void usbdev_trig_deactivate(struct led_classdev *led_cdev)
304 struct usbdev_trig_data *td = led_cdev->trigger_data;
307 usb_unregister_notify(&td->notifier);
309 device_remove_file(led_cdev->dev, &dev_attr_device_name);
310 device_remove_file(led_cdev->dev, &dev_attr_activity_interval);
312 write_lock(&td->lock);
315 usb_put_dev(td->usb_dev);
319 write_unlock(&td->lock);
321 del_timer_sync(&td->timer);
327 static struct led_trigger usbdev_led_trigger = {
329 .activate = usbdev_trig_activate,
330 .deactivate = usbdev_trig_deactivate,
333 static int __init usbdev_trig_init(void)
335 return led_trigger_register(&usbdev_led_trigger);
338 static void __exit usbdev_trig_exit(void)
340 led_trigger_unregister(&usbdev_led_trigger);
343 module_init(usbdev_trig_init);
344 module_exit(usbdev_trig_exit);
346 MODULE_AUTHOR("Gabor Juhos <juhosg@openwrt.org>");
347 MODULE_DESCRIPTION("USB device LED trigger");
348 MODULE_LICENSE("GPL v2");