drivers/watchdog/wafer5823wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/wafer5823wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/wafer5823wdt.c
Extension
.c
Size
7047 bytes
Lines
323
Domain
Driver Families
Bucket
drivers/watchdog
Inferred role
Driver Families: operation-table or driver-model contract
Status
pattern implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

static const struct file_operations wafwdt_fops = {
	.owner		= THIS_MODULE,
	.write		= wafwdt_write,
	.unlocked_ioctl	= wafwdt_ioctl,
	.compat_ioctl	= compat_ptr_ioctl,
	.open		= wafwdt_open,
	.release	= wafwdt_close,
};

static struct miscdevice wafwdt_miscdev = {
	.minor	= WATCHDOG_MINOR,
	.name	= "watchdog",
	.fops	= &wafwdt_fops,
};

/*
 *	The WDT needs to learn about soft shutdowns in order to
 *	turn the timebomb registers off.
 */

static struct notifier_block wafwdt_notifier = {
	.notifier_call = wafwdt_notify_sys,
};

static int __init wafwdt_init(void)
{
	int ret;

	pr_info("WDT driver for Wafer 5823 single board computer initialising\n");

	if (timeout < 1 || timeout > 255) {
		timeout = WD_TIMO;
		pr_info("timeout value must be 1 <= x <= 255, using %d\n",
			timeout);
	}

	if (wdt_stop != wdt_start) {
		if (!request_region(wdt_stop, 1, "Wafer 5823 WDT")) {
			pr_err("I/O address 0x%04x already in use\n", wdt_stop);
			ret = -EIO;
			goto error;
		}
	}

	if (!request_region(wdt_start, 1, "Wafer 5823 WDT")) {
		pr_err("I/O address 0x%04x already in use\n", wdt_start);
		ret = -EIO;
		goto error2;
	}

	ret = register_reboot_notifier(&wafwdt_notifier);
	if (ret != 0) {
		pr_err("cannot register reboot notifier (err=%d)\n", ret);
		goto error3;
	}

	ret = misc_register(&wafwdt_miscdev);
	if (ret != 0) {
		pr_err("cannot register miscdev on minor=%d (err=%d)\n",
		       WATCHDOG_MINOR, ret);
		goto error4;
	}

	pr_info("initialized. timeout=%d sec (nowayout=%d)\n",
		timeout, nowayout);

	return ret;
error4:
	unregister_reboot_notifier(&wafwdt_notifier);
error3:
	release_region(wdt_start, 1);
error2:
	if (wdt_stop != wdt_start)
		release_region(wdt_stop, 1);
error:
	return ret;
}

static void __exit wafwdt_exit(void)
{
	misc_deregister(&wafwdt_miscdev);
	unregister_reboot_notifier(&wafwdt_notifier);
	if (wdt_stop != wdt_start)
		release_region(wdt_stop, 1);
	release_region(wdt_start, 1);
}

module_init(wafwdt_init);
module_exit(wafwdt_exit);

Annotation

Implementation Notes