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 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR) */
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/... */
47 #ifdef CONFIG_USB_DEBUG
53 /* Use our own dbg macro */
59 #define dbg(format, ...) \
62 pr_debug(format "\n", ##__VA_ARGS__); \
65 /* Module and Version Information */
66 #define DRIVER_VERSION "1.02"
67 #define DRIVER_AUTHOR "Wim Van Sebroeck <wim@iguana.be>"
68 #define DRIVER_DESC "Berkshire USB-PC Watchdog driver"
69 #define DRIVER_LICENSE "GPL"
70 #define DRIVER_NAME "pcwd_usb"
72 MODULE_AUTHOR(DRIVER_AUTHOR);
73 MODULE_DESCRIPTION(DRIVER_DESC);
74 MODULE_LICENSE(DRIVER_LICENSE);
75 MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
76 MODULE_ALIAS_MISCDEV(TEMP_MINOR);
78 /* Module Parameters */
79 module_param(debug, int, 0);
80 MODULE_PARM_DESC(debug, "Debug enabled or not");
82 #define WATCHDOG_HEARTBEAT 0 /* default heartbeat =
83 delay-time from dip-switches */
84 static int heartbeat = WATCHDOG_HEARTBEAT;
85 module_param(heartbeat, int, 0);
86 MODULE_PARM_DESC(heartbeat, "Watchdog heartbeat in seconds. "
87 "(0<heartbeat<65536 or 0=delay-time from dip-switches, default="
88 __MODULE_STRING(WATCHDOG_HEARTBEAT) ")");
90 static bool nowayout = WATCHDOG_NOWAYOUT;
91 module_param(nowayout, bool, 0);
92 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
93 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
95 /* The vendor and product id's for the USB-PC Watchdog card */
96 #define USB_PCWD_VENDOR_ID 0x0c98
97 #define USB_PCWD_PRODUCT_ID 0x1140
99 /* table of devices that work with this driver */
100 static struct usb_device_id usb_pcwd_table[] = {
101 { USB_DEVICE(USB_PCWD_VENDOR_ID, USB_PCWD_PRODUCT_ID) },
102 { } /* Terminating entry */
104 MODULE_DEVICE_TABLE(usb, usb_pcwd_table);
106 /* according to documentation max. time to process a command for the USB
107 * watchdog card is 100 or 200 ms, so we give it 250 ms to do it's job */
108 #define USB_COMMAND_TIMEOUT 250
110 /* Watchdog's internal commands */
111 #define CMD_READ_TEMP 0x02 /* Read Temperature;
112 Re-trigger Watchdog */
113 #define CMD_TRIGGER CMD_READ_TEMP
114 #define CMD_GET_STATUS 0x04 /* Get Status Information */
115 #define CMD_GET_FIRMWARE_VERSION 0x08 /* Get Firmware Version */
116 #define CMD_GET_DIP_SWITCH_SETTINGS 0x0c /* Get Dip Switch Settings */
117 #define CMD_READ_WATCHDOG_TIMEOUT 0x18 /* Read Current Watchdog Time */
118 #define CMD_WRITE_WATCHDOG_TIMEOUT 0x19 /* Write Current WatchdogTime */
119 #define CMD_ENABLE_WATCHDOG 0x30 /* Enable / Disable Watchdog */
120 #define CMD_DISABLE_WATCHDOG CMD_ENABLE_WATCHDOG
122 /* Watchdog's Dip Switch heartbeat values */
123 static const int heartbeat_tbl[] = {
124 5, /* OFF-OFF-OFF = 5 Sec */
125 10, /* OFF-OFF-ON = 10 Sec */
126 30, /* OFF-ON-OFF = 30 Sec */
127 60, /* OFF-ON-ON = 1 Min */
128 300, /* ON-OFF-OFF = 5 Min */
129 600, /* ON-OFF-ON = 10 Min */
130 1800, /* ON-ON-OFF = 30 Min */
131 3600, /* ON-ON-ON = 1 hour */
134 /* We can only use 1 card due to the /dev/watchdog restriction */
135 static int cards_found;
137 /* some internal variables */
138 static unsigned long is_active;
139 static char expect_release;
141 /* Structure to hold all of our device specific stuff */
142 struct usb_pcwd_private {
143 /* save off the usb device pointer */
144 struct usb_device *udev;
145 /* the interface for this device */
146 struct usb_interface *interface;
148 /* the interface number used for cmd's */
149 unsigned int interface_number;
151 /* the buffer to intr data */
152 unsigned char *intr_buffer;
153 /* the dma address for the intr buffer */
155 /* the size of the intr buffer */
157 /* the urb used for the intr pipe */
158 struct urb *intr_urb;
160 /* The command that is reported back */
161 unsigned char cmd_command;
162 /* The data MSB that is reported back */
163 unsigned char cmd_data_msb;
164 /* The data LSB that is reported back */
165 unsigned char cmd_data_lsb;
166 /* true if we received a report after a command */
167 atomic_t cmd_received;
169 /* Wether or not the device exists */
171 /* locks this structure */
174 static struct usb_pcwd_private *usb_pcwd_device;
176 /* prevent races between open() and disconnect() */
177 static DEFINE_MUTEX(disconnect_mutex);
179 /* local function prototypes */
180 static int usb_pcwd_probe(struct usb_interface *interface,
181 const struct usb_device_id *id);
182 static void usb_pcwd_disconnect(struct usb_interface *interface);
184 /* usb specific object needed to register this driver with the usb subsystem */
185 static struct usb_driver usb_pcwd_driver = {
187 .probe = usb_pcwd_probe,
188 .disconnect = usb_pcwd_disconnect,
189 .id_table = usb_pcwd_table,
193 static void usb_pcwd_intr_done(struct urb *urb)
195 struct usb_pcwd_private *usb_pcwd =
196 (struct usb_pcwd_private *)urb->context;
197 unsigned char *data = usb_pcwd->intr_buffer;
200 switch (urb->status) {
201 case 0: /* success */
203 case -ECONNRESET: /* unlink */
206 /* this urb is terminated, clean up */
207 dbg("%s - urb shutting down with status: %d", __func__,
210 /* -EPIPE: should clear the halt */
212 dbg("%s - nonzero urb status received: %d", __func__,
217 dbg("received following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
218 data[0], data[1], data[2]);
220 usb_pcwd->cmd_command = data[0];
221 usb_pcwd->cmd_data_msb = data[1];
222 usb_pcwd->cmd_data_lsb = data[2];
224 /* notify anyone waiting that the cmd has finished */
225 atomic_set(&usb_pcwd->cmd_received, 1);
228 retval = usb_submit_urb(urb, GFP_ATOMIC);
230 pr_err("can't resubmit intr, usb_submit_urb failed with result %d\n",
234 static int usb_pcwd_send_command(struct usb_pcwd_private *usb_pcwd,
235 unsigned char cmd, unsigned char *msb, unsigned char *lsb)
237 int got_response, count;
240 /* We will not send any commands if the USB PCWD device does
242 if ((!usb_pcwd) || (!usb_pcwd->exists))
245 buf = kmalloc(6, GFP_KERNEL);
249 /* The USB PC Watchdog uses a 6 byte report format.
250 * The board currently uses only 3 of the six bytes of the report. */
251 buf[0] = cmd; /* Byte 0 = CMD */
252 buf[1] = *msb; /* Byte 1 = Data MSB */
253 buf[2] = *lsb; /* Byte 2 = Data LSB */
254 buf[3] = buf[4] = buf[5] = 0; /* All other bytes not used */
256 dbg("sending following data cmd=0x%02x msb=0x%02x lsb=0x%02x",
257 buf[0], buf[1], buf[2]);
259 atomic_set(&usb_pcwd->cmd_received, 0);
261 if (usb_control_msg(usb_pcwd->udev, usb_sndctrlpipe(usb_pcwd->udev, 0),
262 HID_REQ_SET_REPORT, HID_DT_REPORT,
263 0x0200, usb_pcwd->interface_number, buf, sizeof(buf),
264 USB_COMMAND_TIMEOUT) != sizeof(buf)) {
265 dbg("usb_pcwd_send_command: error in usb_control_msg for "
266 "cmd 0x%x 0x%x 0x%x\n", cmd, *msb, *lsb);
268 /* wait till the usb card processed the command,
269 * with a max. timeout of USB_COMMAND_TIMEOUT */
271 for (count = 0; (count < USB_COMMAND_TIMEOUT) && (!got_response);
274 if (atomic_read(&usb_pcwd->cmd_received))
278 if ((got_response) && (cmd == usb_pcwd->cmd_command)) {
279 /* read back response */
280 *msb = usb_pcwd->cmd_data_msb;
281 *lsb = usb_pcwd->cmd_data_lsb;
289 static int usb_pcwd_start(struct usb_pcwd_private *usb_pcwd)
291 unsigned char msb = 0x00;
292 unsigned char lsb = 0x00;
295 /* Enable Watchdog */
296 retval = usb_pcwd_send_command(usb_pcwd, CMD_ENABLE_WATCHDOG,
299 if ((retval == 0) || (lsb == 0)) {
300 pr_err("Card did not acknowledge enable attempt\n");
307 static int usb_pcwd_stop(struct usb_pcwd_private *usb_pcwd)
309 unsigned char msb = 0xA5;
310 unsigned char lsb = 0xC3;
313 /* Disable Watchdog */
314 retval = usb_pcwd_send_command(usb_pcwd, CMD_DISABLE_WATCHDOG,
317 if ((retval == 0) || (lsb != 0)) {
318 pr_err("Card did not acknowledge disable attempt\n");
325 static int usb_pcwd_keepalive(struct usb_pcwd_private *usb_pcwd)
329 /* Re-trigger Watchdog */
330 usb_pcwd_send_command(usb_pcwd, CMD_TRIGGER, &dummy, &dummy);
335 static int usb_pcwd_set_heartbeat(struct usb_pcwd_private *usb_pcwd, int t)
337 unsigned char msb = t / 256;
338 unsigned char lsb = t % 256;
340 if ((t < 0x0001) || (t > 0xFFFF))
343 /* Write new heartbeat to watchdog */
344 usb_pcwd_send_command(usb_pcwd, CMD_WRITE_WATCHDOG_TIMEOUT, &msb, &lsb);
350 static int usb_pcwd_get_temperature(struct usb_pcwd_private *usb_pcwd,
353 unsigned char msb, lsb;
355 usb_pcwd_send_command(usb_pcwd, CMD_READ_TEMP, &msb, &lsb);
358 * Convert celsius to fahrenheit, since this was
359 * the decided 'standard' for this return value.
361 *temperature = (lsb * 9 / 5) + 32;
366 static int usb_pcwd_get_timeleft(struct usb_pcwd_private *usb_pcwd,
369 unsigned char msb, lsb;
371 /* Read the time that's left before rebooting */
372 /* Note: if the board is not yet armed then we will read 0xFFFF */
373 usb_pcwd_send_command(usb_pcwd, CMD_READ_WATCHDOG_TIMEOUT, &msb, &lsb);
375 *time_left = (msb << 8) + lsb;
381 * /dev/watchdog handling
384 static ssize_t usb_pcwd_write(struct file *file, const char __user *data,
385 size_t len, loff_t *ppos)
387 /* See if we got the magic character 'V' and reload the timer */
392 /* note: just in case someone wrote the magic character
393 * five months ago... */
396 /* scan to see whether or not we got the
398 for (i = 0; i != len; i++) {
400 if (get_user(c, data + i))
407 /* someone wrote to us, we should reload the timer */
408 usb_pcwd_keepalive(usb_pcwd_device);
413 static long usb_pcwd_ioctl(struct file *file, unsigned int cmd,
416 void __user *argp = (void __user *)arg;
417 int __user *p = argp;
418 static const struct watchdog_info ident = {
419 .options = WDIOF_KEEPALIVEPING |
422 .firmware_version = 1,
423 .identity = DRIVER_NAME,
427 case WDIOC_GETSUPPORT:
428 return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
430 case WDIOC_GETSTATUS:
431 case WDIOC_GETBOOTSTATUS:
432 return put_user(0, p);
438 if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
441 return put_user(temperature, p);
444 case WDIOC_SETOPTIONS:
446 int new_options, retval = -EINVAL;
448 if (get_user(new_options, p))
451 if (new_options & WDIOS_DISABLECARD) {
452 usb_pcwd_stop(usb_pcwd_device);
456 if (new_options & WDIOS_ENABLECARD) {
457 usb_pcwd_start(usb_pcwd_device);
464 case WDIOC_KEEPALIVE:
465 usb_pcwd_keepalive(usb_pcwd_device);
468 case WDIOC_SETTIMEOUT:
472 if (get_user(new_heartbeat, p))
475 if (usb_pcwd_set_heartbeat(usb_pcwd_device, new_heartbeat))
478 usb_pcwd_keepalive(usb_pcwd_device);
482 case WDIOC_GETTIMEOUT:
483 return put_user(heartbeat, p);
485 case WDIOC_GETTIMELEFT:
489 if (usb_pcwd_get_timeleft(usb_pcwd_device, &time_left))
492 return put_user(time_left, p);
500 static int usb_pcwd_open(struct inode *inode, struct file *file)
502 /* /dev/watchdog can only be opened once */
503 if (test_and_set_bit(0, &is_active))
507 usb_pcwd_start(usb_pcwd_device);
508 usb_pcwd_keepalive(usb_pcwd_device);
509 return nonseekable_open(inode, file);
512 static int usb_pcwd_release(struct inode *inode, struct file *file)
515 * Shut off the timer.
517 if (expect_release == 42) {
518 usb_pcwd_stop(usb_pcwd_device);
520 pr_crit("Unexpected close, not stopping watchdog!\n");
521 usb_pcwd_keepalive(usb_pcwd_device);
524 clear_bit(0, &is_active);
529 * /dev/temperature handling
532 static ssize_t usb_pcwd_temperature_read(struct file *file, char __user *data,
533 size_t len, loff_t *ppos)
537 if (usb_pcwd_get_temperature(usb_pcwd_device, &temperature))
540 if (copy_to_user(data, &temperature, 1))
546 static int usb_pcwd_temperature_open(struct inode *inode, struct file *file)
548 return nonseekable_open(inode, file);
551 static int usb_pcwd_temperature_release(struct inode *inode, struct file *file)
560 static int usb_pcwd_notify_sys(struct notifier_block *this, unsigned long code,
563 if (code == SYS_DOWN || code == SYS_HALT)
564 usb_pcwd_stop(usb_pcwd_device); /* Turn the WDT off */
573 static const struct file_operations usb_pcwd_fops = {
574 .owner = THIS_MODULE,
576 .write = usb_pcwd_write,
577 .unlocked_ioctl = usb_pcwd_ioctl,
578 .open = usb_pcwd_open,
579 .release = usb_pcwd_release,
582 static struct miscdevice usb_pcwd_miscdev = {
583 .minor = WATCHDOG_MINOR,
585 .fops = &usb_pcwd_fops,
588 static const struct file_operations usb_pcwd_temperature_fops = {
589 .owner = THIS_MODULE,
591 .read = usb_pcwd_temperature_read,
592 .open = usb_pcwd_temperature_open,
593 .release = usb_pcwd_temperature_release,
596 static struct miscdevice usb_pcwd_temperature_miscdev = {
598 .name = "temperature",
599 .fops = &usb_pcwd_temperature_fops,
602 static struct notifier_block usb_pcwd_notifier = {
603 .notifier_call = usb_pcwd_notify_sys,
609 static inline void usb_pcwd_delete(struct usb_pcwd_private *usb_pcwd)
611 usb_free_urb(usb_pcwd->intr_urb);
612 if (usb_pcwd->intr_buffer != NULL)
613 usb_free_coherent(usb_pcwd->udev, usb_pcwd->intr_size,
614 usb_pcwd->intr_buffer, usb_pcwd->intr_dma);
621 * Called by the usb core when a new device is connected that it thinks
622 * this driver might be interested in.
624 static int usb_pcwd_probe(struct usb_interface *interface,
625 const struct usb_device_id *id)
627 struct usb_device *udev = interface_to_usbdev(interface);
628 struct usb_host_interface *iface_desc;
629 struct usb_endpoint_descriptor *endpoint;
630 struct usb_pcwd_private *usb_pcwd = NULL;
632 int retval = -ENOMEM;
634 unsigned char fw_rev_major, fw_rev_minor;
636 unsigned char option_switches, dummy;
639 if (cards_found > 1) {
640 pr_err("This driver only supports 1 device\n");
644 /* get the active interface descriptor */
645 iface_desc = interface->cur_altsetting;
647 /* check out that we have a HID device */
648 if (!(iface_desc->desc.bInterfaceClass == USB_CLASS_HID)) {
649 pr_err("The device isn't a Human Interface Device\n");
653 /* check out the endpoint: it has to be Interrupt & IN */
654 endpoint = &iface_desc->endpoint[0].desc;
656 if (!usb_endpoint_is_int_in(endpoint)) {
657 /* we didn't find a Interrupt endpoint with direction IN */
658 pr_err("Couldn't find an INTR & IN endpoint\n");
662 /* get a handle to the interrupt data pipe */
663 pipe = usb_rcvintpipe(udev, endpoint->bEndpointAddress);
664 maxp = usb_maxpacket(udev, pipe, usb_pipeout(pipe));
666 /* allocate memory for our device and initialize it */
667 usb_pcwd = kzalloc(sizeof(struct usb_pcwd_private), GFP_KERNEL);
668 if (usb_pcwd == NULL) {
669 pr_err("Out of memory\n");
673 usb_pcwd_device = usb_pcwd;
675 mutex_init(&usb_pcwd->mtx);
676 usb_pcwd->udev = udev;
677 usb_pcwd->interface = interface;
678 usb_pcwd->interface_number = iface_desc->desc.bInterfaceNumber;
679 usb_pcwd->intr_size = (le16_to_cpu(endpoint->wMaxPacketSize) > 8 ?
680 le16_to_cpu(endpoint->wMaxPacketSize) : 8);
682 /* set up the memory buffer's */
683 usb_pcwd->intr_buffer = usb_alloc_coherent(udev, usb_pcwd->intr_size,
684 GFP_ATOMIC, &usb_pcwd->intr_dma);
685 if (!usb_pcwd->intr_buffer) {
686 pr_err("Out of memory\n");
690 /* allocate the urb's */
691 usb_pcwd->intr_urb = usb_alloc_urb(0, GFP_KERNEL);
692 if (!usb_pcwd->intr_urb) {
693 pr_err("Out of memory\n");
697 /* initialise the intr urb's */
698 usb_fill_int_urb(usb_pcwd->intr_urb, udev, pipe,
699 usb_pcwd->intr_buffer, usb_pcwd->intr_size,
700 usb_pcwd_intr_done, usb_pcwd, endpoint->bInterval);
701 usb_pcwd->intr_urb->transfer_dma = usb_pcwd->intr_dma;
702 usb_pcwd->intr_urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
704 /* register our interrupt URB with the USB system */
705 if (usb_submit_urb(usb_pcwd->intr_urb, GFP_KERNEL)) {
706 pr_err("Problem registering interrupt URB\n");
707 retval = -EIO; /* failure */
711 /* The device exists and can be communicated with */
712 usb_pcwd->exists = 1;
715 usb_pcwd_stop(usb_pcwd);
717 /* Get the Firmware Version */
718 got_fw_rev = usb_pcwd_send_command(usb_pcwd, CMD_GET_FIRMWARE_VERSION,
719 &fw_rev_major, &fw_rev_minor);
721 sprintf(fw_ver_str, "%u.%02u", fw_rev_major, fw_rev_minor);
723 sprintf(fw_ver_str, "<card no answer>");
725 pr_info("Found card (Firmware: %s) with temp option\n", fw_ver_str);
727 /* Get switch settings */
728 usb_pcwd_send_command(usb_pcwd, CMD_GET_DIP_SWITCH_SETTINGS, &dummy,
731 pr_info("Option switches (0x%02x): Temperature Reset Enable=%s, Power On Delay=%s\n",
733 ((option_switches & 0x10) ? "ON" : "OFF"),
734 ((option_switches & 0x08) ? "ON" : "OFF"));
736 /* If heartbeat = 0 then we use the heartbeat from the dip-switches */
738 heartbeat = heartbeat_tbl[(option_switches & 0x07)];
740 /* Check that the heartbeat value is within it's range ;
741 * if not reset to the default */
742 if (usb_pcwd_set_heartbeat(usb_pcwd, heartbeat)) {
743 usb_pcwd_set_heartbeat(usb_pcwd, WATCHDOG_HEARTBEAT);
744 pr_info("heartbeat value must be 0<heartbeat<65536, using %d\n",
748 retval = register_reboot_notifier(&usb_pcwd_notifier);
750 pr_err("cannot register reboot notifier (err=%d)\n", retval);
754 retval = misc_register(&usb_pcwd_temperature_miscdev);
756 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
758 goto err_out_unregister_reboot;
761 retval = misc_register(&usb_pcwd_miscdev);
763 pr_err("cannot register miscdev on minor=%d (err=%d)\n",
764 WATCHDOG_MINOR, retval);
765 goto err_out_misc_deregister;
768 /* we can register the device now, as it is ready */
769 usb_set_intfdata(interface, usb_pcwd);
771 pr_info("initialized. heartbeat=%d sec (nowayout=%d)\n",
772 heartbeat, nowayout);
776 err_out_misc_deregister:
777 misc_deregister(&usb_pcwd_temperature_miscdev);
778 err_out_unregister_reboot:
779 unregister_reboot_notifier(&usb_pcwd_notifier);
782 usb_pcwd_delete(usb_pcwd);
783 usb_pcwd_device = NULL;
789 * usb_pcwd_disconnect
791 * Called by the usb core when the device is removed from the system.
793 * This routine guarantees that the driver will not submit any more urbs
794 * by clearing dev->udev.
796 static void usb_pcwd_disconnect(struct usb_interface *interface)
798 struct usb_pcwd_private *usb_pcwd;
800 /* prevent races with open() */
801 mutex_lock(&disconnect_mutex);
803 usb_pcwd = usb_get_intfdata(interface);
804 usb_set_intfdata(interface, NULL);
806 mutex_lock(&usb_pcwd->mtx);
808 /* Stop the timer before we leave */
810 usb_pcwd_stop(usb_pcwd);
812 /* We should now stop communicating with the USB PCWD device */
813 usb_pcwd->exists = 0;
816 misc_deregister(&usb_pcwd_miscdev);
817 misc_deregister(&usb_pcwd_temperature_miscdev);
818 unregister_reboot_notifier(&usb_pcwd_notifier);
820 mutex_unlock(&usb_pcwd->mtx);
822 /* Delete the USB PCWD device */
823 usb_pcwd_delete(usb_pcwd);
827 mutex_unlock(&disconnect_mutex);
829 pr_info("USB PC Watchdog disconnected\n");
832 module_usb_driver(usb_pcwd_driver);