drivers/watchdog/ep93xx_wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/ep93xx_wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/ep93xx_wdt.c
Extension
.c
Size
3547 bytes
Lines
144
Domain
Driver Families
Bucket
drivers/watchdog
Inferred role
Driver Families: implementation source
Status
source 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

struct ep93xx_wdt_priv {
	void __iomem *mmio;
	struct watchdog_device wdd;
};

static int ep93xx_wdt_start(struct watchdog_device *wdd)
{
	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

	writel(0xaaaa, priv->mmio + EP93XX_WATCHDOG);

	return 0;
}

static int ep93xx_wdt_stop(struct watchdog_device *wdd)
{
	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

	writel(0xaa55, priv->mmio + EP93XX_WATCHDOG);

	return 0;
}

static int ep93xx_wdt_ping(struct watchdog_device *wdd)
{
	struct ep93xx_wdt_priv *priv = watchdog_get_drvdata(wdd);

	writel(0x5555, priv->mmio + EP93XX_WATCHDOG);

	return 0;
}

static const struct watchdog_info ep93xx_wdt_ident = {
	.options	= WDIOF_CARDRESET |
			  WDIOF_SETTIMEOUT |
			  WDIOF_MAGICCLOSE |
			  WDIOF_KEEPALIVEPING,
	.identity	= "EP93xx Watchdog",
};

static const struct watchdog_ops ep93xx_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= ep93xx_wdt_start,
	.stop		= ep93xx_wdt_stop,
	.ping		= ep93xx_wdt_ping,
};

static int ep93xx_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct ep93xx_wdt_priv *priv;
	struct watchdog_device *wdd;
	unsigned long val;
	int ret;

	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
	if (!priv)
		return -ENOMEM;

	priv->mmio = devm_platform_ioremap_resource(pdev, 0);
	if (IS_ERR(priv->mmio))
		return PTR_ERR(priv->mmio);

	val = readl(priv->mmio + EP93XX_WATCHDOG);

	wdd = &priv->wdd;
	wdd->bootstatus = (val & 0x01) ? WDIOF_CARDRESET : 0;
	wdd->info = &ep93xx_wdt_ident;
	wdd->ops = &ep93xx_wdt_ops;
	wdd->min_timeout = 1;
	wdd->max_hw_heartbeat_ms = 200;
	wdd->parent = dev;

	watchdog_set_nowayout(wdd, nowayout);

	wdd->timeout = WDT_TIMEOUT;
	watchdog_init_timeout(wdd, timeout, dev);

	watchdog_set_drvdata(wdd, priv);

	ret = devm_watchdog_register_device(dev, wdd);
	if (ret)
		return ret;

	dev_info(dev, "EP93XX watchdog driver %s\n",
		 (val & 0x08) ? " (nCS1 disable detected)" : "");

	return 0;
}

Annotation

Implementation Notes