2 * Berkshire USB-PC Watchdog Card Driver
4 * (c) Copyright 2004-2007 Wim Van Sebroeck <wim@iguana.be>.
6 * Based on source code of the following authors:
7 * Ken Hollis <kenji@bitgate.com>,
8 * Alan Cox <alan@lxorguk.ukuu.org.uk>,
9 * Matt Domsch <Matt_Domsch@dell.com>,
10 * Rob Radez <rob@osinvestor.com>,
11 * Greg Kroah-Hartman <greg@kroah.com>
13 * This program is free software; you can redistribute it and/or
14 * modify it under the terms of the GNU General Public License
15 * as published by the Free Software Foundation; either version
16 * 2 of the License, or (at your option) any later version.
18 * Neither Wim Van Sebroeck nor Iguana vzw. admit liability nor
19 * provide warranty for any of this software. This material is
20 * provided "AS-IS" and at no charge.
22 * Thanks also to Simon Machell at Berkshire Products Inc. for
23 * providing the test hardware. More info is available at
24 * http://www.berkprod.com/ or http://www.pcwatchdog.com/
27 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
29 #include <linux/module.h> /* For module specific items */
30 #include <linux/moduleparam.h> /* For new moduleparam's */
31 #include <linux/types.h> /* For standard types (like size_t) */
32 #include <linux/errno.h> /* For the -ENODEV/... values */
33 #include <linux/kernel.h> /* For printk/panic/... */
34 #include <linux/delay.h> /* For mdelay function */
35 #include <linux/miscdevice.h> /* For struct miscdevice */
36 #include <linux/watchdog.h> /* For the watchdog specific items */
37 #include <linux/notifier.h> /* For notifier support */
38 #include <linux/reboot.h> /* For reboot_notifier stuff */
39 #include <linux/init.h> /* For __init/__exit/... */
40 #include <linux/fs.h> /* For file operations */
41 #include <linux/usb.h> /* For USB functions */
42 #include <linux/slab.h> /* For kmalloc, ... */
43 #include <linux/mutex.h> /* For mutex locking */
44 #include <linux/hid.h> /* For HID_REQ_SET_REPORT & HID_DT_REPORT */
45 #include <linux/uaccess.h> /* For copy_to_user/put_user/... */
48 /* Module and Version Information */
49 #define DRIVER_VERSION "1.02"
50 #define DRIVER_AUTHOR "Wim Van Sebroeck <wim@iguana.be>"
51 #define DRIVER_DESC "Berkshire USB-PC Watchdog driver"
52 #define DRIVER_LICENSE "GPL"
53 #define DRIVER_NAME "pcwd_usb"
55 MODULE_AUTHOR(DRIVER_AUTHOR);
56 MODULE_DESCRIPTION(DRIVER_DESC);
57 MODULE_LICENSE(DRIVER_LICENSE);
59 #define WATCHDOG_HEARTBEAT 0 /* default heartbeat =
60 delay-time from dip-switches */
61 static int heartbeat = WATCHDOG_HEARTBEAT;
62 module_param(heartbeat, int, 0);
63 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. "
64 "(0<heartbeat<65536 or 0=delay-time from dip-switches, default="
65 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
67 static bool nowayout = WATCHDOG_NOWAYOUT;
68 module_param(nowayout, bool, 0);
69 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
70 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
72 /* The vendor and product id's for the USB-PC Watchdog card */
73 #define USB_PCWD_VENDOR_ID 0x0c98
74 #define USB_PCWD_PRODUCT_ID 0x1140
76 /* table of devices that work with this driver */
77 static struct usb_device_id usb_pcwd_table[] = {
78 { USB_DEVICE(USB_PCWD_VENDOR_ID, USB_PCWD_PRODUCT_ID) },
79 { } /* Terminating entry */
81 MODULE_DEVICE_TABLE(usb, usb_pcwd_table);
83 /* according to documentation max. time to process a command for the USB
84 * watchdog card is 100 or 200 ms, so we give it 250 ms to do it's job */
85 #define USB_COMMAND_TIMEOUT 250
87 /* Watchdog's internal commands */
88 #define CMD_READ_TEMP 0x02 /* Read Temperature;
89 Re-trigger Watchdog */
90 #define CMD_TRIGGER CMD_READ_TEMP
91 #define CMD_GET_STATUS 0x04 /* Get Status Information */
92 #define CMD_GET_FIRMWARE_VERSION 0x08 /* Get Firmware Version */
93 #define CMD_GET_DIP_SWITCH_SETTINGS 0x0c /* Get Dip Switch Settings */
94 #define CMD_READ_WATCHDOG_TIMEOUT 0x18 /* Read Current Watchdog Time */
95 #define CMD_WRITE_WATCHDOG_TIMEOUT 0x19 /* Write Current WatchdogTime */
96 #define CMD_ENABLE_WATCHDOG 0x30 /* Enable / Disable Watchdog */
97 #define CMD_DISABLE_WATCHDOG CMD_ENABLE_WATCHDOG
99 /* Watchdog's Dip Switch heartbeat values */
100 static const int heartbeat_tbl[] = {
101 5, /* OFF-OFF-OFF = 5 Sec */
102 10, /* OFF-OFF-ON = 10 Sec */
103 30, /* OFF-ON-OFF = 30 Sec */
104 60, /* OFF-ON-ON = 1 Min */
105 300, /* ON-OFF-OFF = 5 Min */
106 600, /* ON-OFF-ON = 10 Min */
107 1800, /* ON-ON-OFF = 30 Min */
108 3600, /* ON-ON-ON = 1 hour */
111 /* We can only use 1 card due to the /dev/watchdog restriction */
112 static int cards_found;
114 /* some internal variables */
115 static unsigned long is_active;
116 static char expect_release;
118 /* Structure to hold all of our device specific stuff */
119 struct usb_pcwd_private {
120 /* save off the usb device pointer */
121 struct usb_device *udev;
122 /* the interface for this device */
123 struct usb_interface *interface;
125 /* the interface number used for cmd's */
126 unsigned int interface_number;
128 /* the buffer to intr data */
129 unsigned char *intr_buffer;
130 /* the dma address for the intr buffer */
132 /* the size of the intr buffer */
134 /* the urb used for the intr pipe */
135 struct urb *intr_urb;
137 /* The command that is reported back */
138 unsigned char cmd_command;
139 /* The data MSB that is reported back */
140 unsigned char cmd_data_msb;
141 /* The data LSB that is reported back */
142 unsigned char cmd_data_lsb;
143 /* true if we received a report after a command */
144 atomic_t cmd_received;
146 /* Wether or not the device exists */
148 /* locks this structure */
151 static struct usb_pcwd_private *usb_pcwd_device;
153 /* prevent races between open() and disconnect() */
154 static DEFINE_MUTEX(disconnect_mutex);
156 /* local function prototypes */
157 static int usb_pcwd_probe(struct usb_interface *interface,
158 const struct usb_device_id *id);
159 static void usb_pcwd_disconnect(struct usb_interface *interface);
161 /* usb specific object needed to register this driver with the usb subsystem */
162 static struct usb_driver usb_pcwd_driver = {
164 .probe = usb_pcwd_probe,
165 .disconnect = usb_pcwd_disconnect,
166 .id_table = usb_pcwd_table,
170 static void usb_pcwd_intr_done(struct urb *urb)
172 struct usb_pcwd_private *usb_pcwd =
173 (struct usb_pcwd_private *)urb->context;
174 unsigned char *data = usb_pcwd->intr_buffer;
175 struct device *dev = &usb_pcwd->interface->dev;
178 switch (urb->status) {
179 case 0: /* success */
181 case -ECONNRESET: /* unlink */
184 /* this urb is terminated, clean up */
185 dev_dbg(dev, "%s - urb shutting down with status: %d",
186 __func__, urb->status);
188 /* -EPIPE: should clear the halt */
190 dev_dbg(dev, "%s - nonzero urb status received: %d",
191 __func__, urb->status);
195 dev_dbg(dev, "received following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
196 data[0], data[1], data[2]);
198 usb_pcwd->cmd_command = data[0];
199 usb_pcwd->cmd_data_msb = data[1];
200 usb_pcwd->cmd_data_lsb = data[2];
202 /* notify anyone waiting that the cmd has finished */
203 atomic_set(&usb_pcwd->cmd_received, 1);
206 retval = usb_submit_urb(urb, GFP_ATOMIC);
208 pr_err("can't resubmit intr, usb_submit_urb failed with result %d\n",
212 static int usb_pcwd_send_command(struct usb_pcwd_private *usb_pcwd,
213 unsigned char cmd, unsigned char *msb, unsigned char *lsb)
215 int got_response, count;
218 /* We will not send any commands if the USB PCWD device does
220 if ((!usb_pcwd) || (!usb_pcwd->exists))
223 buf = kmalloc(6, GFP_KERNEL);
227 /* The USB PC Watchdog uses a 6 byte report format.
228 * The board currently uses only 3 of the six bytes of the report. */
229 buf[0] = cmd; /* Byte 0 = CMD */
230 buf[1] = *msb; /* Byte 1 = Data MSB */
231 buf[2] = *lsb; /* Byte 2 = Data LSB */
232 buf[3] = buf[4] = buf[5] = 0; /* All other bytes not used */
234 dev_dbg(&usb_pcwd->interface->dev,
235 "sending following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
236 buf[0], buf[1], buf[2]);
238 atomic_set(&usb_pcwd->cmd_received, 0);
240 if (usb_control_msg(usb_pcwd->udev, usb_sndctrlpipe(usb_pcwd->udev, 0),
241 HID_REQ_SET_REPORT, HID_DT_REPORT,
242 0x0200, usb_pcwd->interface_number, buf, 6,
243 USB_COMMAND_TIMEOUT) != 6) {
244 dev_dbg(&usb_pcwd->interface->dev,
245 "usb_pcwd_send_command: error in usb_control_msg for cmd 0x%x 0x%x 0x%x\n",
248 /* wait till the usb card processed the command,
249 * with a max. timeout of USB_COMMAND_TIMEOUT */
251 for (count = 0; (count < USB_COMMAND_TIMEOUT) && (!got_response);
254 if (atomic_read(&usb_pcwd->cmd_received))
258 if ((got_response) && (cmd == usb_pcwd->cmd_command)) {
259 /* read back response */
260 *msb = usb_pcwd->cmd_data_msb;
261 *lsb = usb_pcwd->cmd_data_lsb;
269 static int usb_pcwd_start(struct usb_pcwd_private *usb_pcwd)
271 unsigned char msb = 0x00;
272 unsigned char lsb = 0x00;
275 /* Enable Watchdog */
276 retval = usb_pcwd_send_command(usb_pcwd, CMD_ENABLE_WATCHDOG,
279 if ((retval == 0) || (lsb == 0)) {
280 pr_err("Card did not acknowledge enable attempt\n");
287 static int usb_pcwd_stop(struct usb_pcwd_private *usb_pcwd)
289 unsigned char msb = 0xA5;
290 unsigned char lsb = 0xC3;
293 /* Disable Watchdog */
294 retval = usb_pcwd_send_command(usb_pcwd, CMD_DISABLE_WATCHDOG,
297 if ((retval == 0) || (lsb != 0)) {
298 pr_err("Card did not acknowledge disable attempt\n");
305 static int usb_pcwd_keepalive(struct usb_pcwd_private *usb_pcwd)
309 /* Re-trigger Watchdog */
310 usb_pcwd_send_command(usb_pcwd, CMD_TRIGGER, &dummy, &dummy);
315 static int usb_pcwd_set_heartbeat(struct usb_pcwd_private *usb_pcwd, int t)
317 unsigned char msb = t / 256;
318 unsigned char lsb = t % 256;
320 if ((t < 0x0001) || (t > 0xFFFF))
323 /* Write new heartbeat to watchdog */
324 usb_pcwd_send_command(usb_pcwd, CMD_WRITE_WATCHDOG_TIMEOUT, &msb, &lsb);
330 static int usb_pcwd_get_temperature(struct usb_pcwd_private *usb_pcwd,
333 unsigned char msb, lsb;
335 usb_pcwd_send_command(usb_pcwd, CMD_READ_TEMP, &msb, &lsb);
338 * Convert celsius to fahrenheit, since this was
339 * the decided 'standard' for this return value.
341 *temperature = (lsb * 9 / 5) + 32;
346 static int usb_pcwd_get_timeleft(struct usb_pcwd_private *usb_pcwd,
349 unsigned char msb, lsb;
351 /* Read the time that's left before rebooting */
352 /* Note: if the board is not yet armed then we will read 0xFFFF */
353 usb_pcwd_send_command(usb_pcwd, CMD_READ_WATCHDOG_TIMEOUT, &msb, &lsb);
355 *time_left = (msb << 8) + lsb;
361 * /dev/watchdog handling
364 static ssize_t usb_pcwd_write(struct file *file, const char __user *data,
365 size_t len, loff_t *ppos)
367 /* See if we got the magic character 'V' and reload the timer */
372 /* note: just in case someone wrote the magic character
373 * five months ago... */
376 /* scan to see whether or not we got the
378 for (i = 0; i != len; i++) {
380 if (get_user(c, data + i))
387 /* someone wrote to us, we should reload the timer */
388 usb_pcwd_keepalive(usb_pcwd_device);
393 static long usb_pcwd_ioctl(struct file *file, unsigned int cmd,
396 void __user *argp = (void __user *)arg;
397 int __user *p = argp;
398 static const struct watchdog_info ident = {
399 .options = WDIOF_KEEPALIVEPING |
402 .firmware_version = 1,
403 .identity = DRIVER_NAME,
407 case WDIOC_GETSUPPORT:
408 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
410 case WDIOC_GETSTATUS:
411 case WDIOC_GETBOOTSTATUS:
412 return put_user(0, p);
418 if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
421 return put_user(temperature, p);
424 case WDIOC_SETOPTIONS:
426 int new_options, retval = -EINVAL;
428 if (get_user(new_options, p))
431 if (new_options & WDIOS_DISABLECARD) {
432 usb_pcwd_stop(usb_pcwd_device);
436 if (new_options & WDIOS_ENABLECARD) {
437 usb_pcwd_start(usb_pcwd_device);
444 case WDIOC_KEEPALIVE:
445 usb_pcwd_keepalive(usb_pcwd_device);
448 case WDIOC_SETTIMEOUT:
452 if (get_user(new_heartbeat, p))
455 if (usb_pcwd_set_heartbeat(usb_pcwd_device, new_heartbeat))
458 usb_pcwd_keepalive(usb_pcwd_device);
462 case WDIOC_GETTIMEOUT:
463 return put_user(heartbeat, p);
465 case WDIOC_GETTIMELEFT:
469 if (usb_pcwd_get_timeleft(usb_pcwd_device, &time_left))
472 return put_user(time_left, p);
480 static int usb_pcwd_open(struct inode *inode, struct file *file)
482 /* /dev/watchdog can only be opened once */
483 if (test_and_set_bit(0, &is_active))
487 usb_pcwd_start(usb_pcwd_device);
488 usb_pcwd_keepalive(usb_pcwd_device);
489 return nonseekable_open(inode, file);
492 static int usb_pcwd_release(struct inode *inode, struct file *file)
495 * Shut off the timer.
497 if (expect_release == 42) {
498 usb_pcwd_stop(usb_pcwd_device);
500 pr_crit("Unexpected close, not stopping watchdog!\n");
501 usb_pcwd_keepalive(usb_pcwd_device);
504 clear_bit(0, &is_active);
509 * /dev/temperature handling
512 static ssize_t usb_pcwd_temperature_read(struct file *file, char __user *data,
513 size_t len, loff_t *ppos)
517 if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
520 if (copy_to_user(data, &temperature, 1))
526 static int usb_pcwd_temperature_open(struct inode *inode, struct file *file)
528 return nonseekable_open(inode, file);
531 static int usb_pcwd_temperature_release(struct inode *inode, struct file *file)
540 static int usb_pcwd_notify_sys(struct notifier_block *this, unsigned long code,
543 if (code == SYS_DOWN || code == SYS_HALT)
544 usb_pcwd_stop(usb_pcwd_device); /* Turn the WDT off */
553 static const struct file_operations usb_pcwd_fops = {
554 .owner = THIS_MODULE,
556 .write = usb_pcwd_write,
557 .unlocked_ioctl = usb_pcwd_ioctl,
558 .open = usb_pcwd_open,
559 .release = usb_pcwd_release,
562 static struct miscdevice usb_pcwd_miscdev = {
563 .minor = WATCHDOG_MINOR,
565 .fops = &usb_pcwd_fops,
568 static const struct file_operations usb_pcwd_temperature_fops = {
569 .owner = THIS_MODULE,
571 .read = usb_pcwd_temperature_read,
572 .open = usb_pcwd_temperature_open,
573 .release = usb_pcwd_temperature_release,
576 static struct miscdevice usb_pcwd_temperature_miscdev = {
578 .name = "temperature",
579 .fops = &usb_pcwd_temperature_fops,
582 static struct notifier_block usb_pcwd_notifier = {
583 .notifier_call = usb_pcwd_notify_sys,
589 static inline void usb_pcwd_delete(struct usb_pcwd_private *usb_pcwd)
591 usb_free_urb(usb_pcwd->intr_urb);
592 if (usb_pcwd->intr_buffer != NULL)
593 usb_free_coherent(usb_pcwd->udev, usb_pcwd->intr_size,
594 usb_pcwd->intr_buffer, usb_pcwd->intr_dma);
601 * Called by the usb core when a new device is connected that it thinks
602 * this driver might be interested in.
604 static int usb_pcwd_probe(struct usb_interface *interface,
605 const struct usb_device_id *id)
607 struct usb_device *udev = interface_to_usbdev(interface);
608 struct usb_host_interface *iface_desc;
609 struct usb_endpoint_descriptor *endpoint;
610 struct usb_pcwd_private *usb_pcwd = NULL;
612 int retval = -ENOMEM;
614 unsigned char fw_rev_major, fw_rev_minor;
616 unsigned char option_switches, dummy;
619 if (cards_found > 1) {
620 pr_err("This driver only supports 1 device\n");
624 /* get the active interface descriptor */
625 iface_desc = interface->cur_altsetting;
627 /* check out that we have a HID device */
628 if (!(iface_desc->desc.bInterfaceClass == USB_CLASS_HID)) {
629 pr_err("The device isn't a Human Interface Device\n");
633 /* check out the endpoint: it has to be Interrupt & IN */
634 endpoint = &iface_desc->endpoint[0].desc;
636 if (!usb_endpoint_is_int_in(endpoint)) {
637 /* we didn't find a Interrupt endpoint with direction IN */
638 pr_err("Couldn't find an INTR & IN endpoint\n");
642 /* get a handle to the interrupt data pipe */
643 pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);
644 maxp = usb_maxpacket(udev, pipe, usb_pipeout(pipe));
646 /* allocate memory for our device and initialize it */
647 usb_pcwd = kzalloc(sizeof(struct usb_pcwd_private), GFP_KERNEL);
648 if (usb_pcwd == NULL)
651 usb_pcwd_device = usb_pcwd;
653 mutex_init(&usb_pcwd->mtx);
654 usb_pcwd->udev = udev;
655 usb_pcwd->interface = interface;
656 usb_pcwd->interface_number = iface_desc->desc.bInterfaceNumber;
657 usb_pcwd->intr_size = (le16_to_cpu(endpoint->wMaxPacketSize) > 8 ?
658 le16_to_cpu(endpoint->wMaxPacketSize) : 8);
660 /* set up the memory buffer's */
661 usb_pcwd->intr_buffer = usb_alloc_coherent(udev, usb_pcwd->intr_size,
662 GFP_ATOMIC, &usb_pcwd->intr_dma);
663 if (!usb_pcwd->intr_buffer) {
664 pr_err("Out of memory\n");
668 /* allocate the urb's */
669 usb_pcwd->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
670 if (!usb_pcwd->intr_urb) {
671 pr_err("Out of memory\n");
675 /* initialise the intr urb's */
676 usb_fill_int_urb(usb_pcwd->intr_urb, udev, pipe,
677 usb_pcwd->intr_buffer, usb_pcwd->intr_size,
678 usb_pcwd_intr_done, usb_pcwd, endpoint->bInterval);
679 usb_pcwd->intr_urb->transfer_dma = usb_pcwd->intr_dma;
680 usb_pcwd->intr_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
682 /* register our interrupt URB with the USB system */
683 if (usb_submit_urb(usb_pcwd->intr_urb, GFP_KERNEL)) {
684 pr_err("Problem registering interrupt URB\n");
685 retval = -EIO; /* failure */
689 /* The device exists and can be communicated with */
690 usb_pcwd->exists = 1;
693 usb_pcwd_stop(usb_pcwd);
695 /* Get the Firmware Version */
696 got_fw_rev = usb_pcwd_send_command(usb_pcwd, CMD_GET_FIRMWARE_VERSION,
697 &fw_rev_major, &fw_rev_minor);
699 sprintf(fw_ver_str, "%u.%02u", fw_rev_major, fw_rev_minor);
701 sprintf(fw_ver_str, "<card no answer>");
703 pr_info("Found card (Firmware: %s) with temp option\n", fw_ver_str);
705 /* Get switch settings */
706 usb_pcwd_send_command(usb_pcwd, CMD_GET_DIP_SWITCH_SETTINGS, &dummy,
709 pr_info("Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
711 ((option_switches & 0x10) ? "ON" : "OFF"),
712 ((option_switches & 0x08) ? "ON" : "OFF"));
714 /* If heartbeat = 0 then we use the heartbeat from the dip-switches */
716 heartbeat = heartbeat_tbl[(option_switches & 0x07)];
718 /* Check that the heartbeat value is within it's range ;
719 * if not reset to the default */
720 if (usb_pcwd_set_heartbeat(usb_pcwd, heartbeat)) {
721 usb_pcwd_set_heartbeat(usb_pcwd, WATCHDOG_HEARTBEAT);
722 pr_info("heartbeat value must be 0<heartbeat<65536, using %d\n",
726 retval = register_reboot_notifier(&usb_pcwd_notifier);
728 pr_err("cannot register reboot notifier (err=%d)\n", retval);
732 retval = misc_register(&usb_pcwd_temperature_miscdev);
734 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
736 goto err_out_unregister_reboot;
739 retval = misc_register(&usb_pcwd_miscdev);
741 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
742 WATCHDOG_MINOR, retval);
743 goto err_out_misc_deregister;
746 /* we can register the device now, as it is ready */
747 usb_set_intfdata(interface, usb_pcwd);
749 pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
750 heartbeat, nowayout);
754 err_out_misc_deregister:
755 misc_deregister(&usb_pcwd_temperature_miscdev);
756 err_out_unregister_reboot:
757 unregister_reboot_notifier(&usb_pcwd_notifier);
760 usb_pcwd_delete(usb_pcwd);
761 usb_pcwd_device = NULL;
767 * usb_pcwd_disconnect
769 * Called by the usb core when the device is removed from the system.
771 * This routine guarantees that the driver will not submit any more urbs
772 * by clearing dev->udev.
774 static void usb_pcwd_disconnect(struct usb_interface *interface)
776 struct usb_pcwd_private *usb_pcwd;
778 /* prevent races with open() */
779 mutex_lock(&disconnect_mutex);
781 usb_pcwd = usb_get_intfdata(interface);
782 usb_set_intfdata(interface, NULL);
784 mutex_lock(&usb_pcwd->mtx);
786 /* Stop the timer before we leave */
788 usb_pcwd_stop(usb_pcwd);
790 /* We should now stop communicating with the USB PCWD device */
791 usb_pcwd->exists = 0;
794 misc_deregister(&usb_pcwd_miscdev);
795 misc_deregister(&usb_pcwd_temperature_miscdev);
796 unregister_reboot_notifier(&usb_pcwd_notifier);
798 mutex_unlock(&usb_pcwd->mtx);
800 /* Delete the USB PCWD device */
801 usb_pcwd_delete(usb_pcwd);
805 mutex_unlock(&disconnect_mutex);
807 pr_info("USB PC Watchdog disconnected\n");
810 module_usb_driver(usb_pcwd_driver);