drivers/watchdog/digicolor_wdt.c

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

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/digicolor_wdt.c
Extension
.c
Size
3876 bytes
Lines
164
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 dc_wdt {
	void __iomem		*base;
	struct clk		*clk;
	spinlock_t		lock;
};

static unsigned timeout;
module_param(timeout, uint, 0);
MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds");

static void dc_wdt_set(struct dc_wdt *wdt, u32 ticks)
{
	unsigned long flags;

	spin_lock_irqsave(&wdt->lock, flags);

	writel_relaxed(0, wdt->base + TIMER_A_CONTROL);
	writel_relaxed(ticks, wdt->base + TIMER_A_COUNT);
	writel_relaxed(TIMER_A_ENABLE_COUNT | TIMER_A_ENABLE_WATCHDOG,
		       wdt->base + TIMER_A_CONTROL);

	spin_unlock_irqrestore(&wdt->lock, flags);
}

static int dc_wdt_restart(struct watchdog_device *wdog, unsigned long action,
			  void *data)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	dc_wdt_set(wdt, 1);
	/* wait for reset to assert... */
	mdelay(500);

	return 0;
}

static int dc_wdt_start(struct watchdog_device *wdog)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	dc_wdt_set(wdt, wdog->timeout * clk_get_rate(wdt->clk));

	return 0;
}

static int dc_wdt_stop(struct watchdog_device *wdog)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	writel_relaxed(0, wdt->base + TIMER_A_CONTROL);

	return 0;
}

static int dc_wdt_set_timeout(struct watchdog_device *wdog, unsigned int t)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);

	dc_wdt_set(wdt, t * clk_get_rate(wdt->clk));
	wdog->timeout = t;

	return 0;
}

static unsigned int dc_wdt_get_timeleft(struct watchdog_device *wdog)
{
	struct dc_wdt *wdt = watchdog_get_drvdata(wdog);
	uint32_t count = readl_relaxed(wdt->base + TIMER_A_COUNT);

	return count / clk_get_rate(wdt->clk);
}

static const struct watchdog_ops dc_wdt_ops = {
	.owner		= THIS_MODULE,
	.start		= dc_wdt_start,
	.stop		= dc_wdt_stop,
	.set_timeout	= dc_wdt_set_timeout,
	.get_timeleft	= dc_wdt_get_timeleft,
	.restart        = dc_wdt_restart,
};

static const struct watchdog_info dc_wdt_info = {
	.options	= WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE
			| WDIOF_KEEPALIVEPING,
	.identity	= "Conexant Digicolor Watchdog",
};

static struct watchdog_device dc_wdt_wdd = {
	.info		= &dc_wdt_info,
	.ops		= &dc_wdt_ops,

Annotation

Implementation Notes