drivers/watchdog/ts4800_wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/ts4800_wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/ts4800_wdt.c
Extension
.c
Size
5066 bytes
Lines
206
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 ts4800_wdt {
	struct watchdog_device  wdd;
	struct regmap           *regmap;
	u32                     feed_offset;
	u32                     feed_val;
};

/*
 * TS-4800 supports the following timeout values:
 *
 *   value desc
 *   ---------------------
 *     0    feed for 338ms
 *     1    feed for 2.706s
 *     2    feed for 10.824s
 *     3    disable watchdog
 *
 * Keep the regmap/timeout map ordered by timeout
 */
static const struct {
	const int timeout;
	const int regval;
} ts4800_wdt_map[] = {
	{ 2,  TS4800_WDT_FEED_2S },
	{ 10, TS4800_WDT_FEED_10S },
};

#define MAX_TIMEOUT_INDEX       (ARRAY_SIZE(ts4800_wdt_map) - 1)

static void ts4800_write_feed(struct ts4800_wdt *wdt, u32 val)
{
	regmap_write(wdt->regmap, wdt->feed_offset, val);
}

static int ts4800_wdt_start(struct watchdog_device *wdd)
{
	struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);

	ts4800_write_feed(wdt, wdt->feed_val);
	return 0;
}

static int ts4800_wdt_stop(struct watchdog_device *wdd)
{
	struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);

	ts4800_write_feed(wdt, TS4800_WDT_DISABLE);
	return 0;
}

static int ts4800_wdt_set_timeout(struct watchdog_device *wdd,
				  unsigned int timeout)
{
	struct ts4800_wdt *wdt = watchdog_get_drvdata(wdd);
	int i;

	for (i = 0; i < MAX_TIMEOUT_INDEX; i++) {
		if (ts4800_wdt_map[i].timeout >= timeout)
			break;
	}

	wdd->timeout = ts4800_wdt_map[i].timeout;
	wdt->feed_val = ts4800_wdt_map[i].regval;

	return 0;
}

static const struct watchdog_ops ts4800_wdt_ops = {
	.owner = THIS_MODULE,
	.start = ts4800_wdt_start,
	.stop = ts4800_wdt_stop,
	.set_timeout = ts4800_wdt_set_timeout,
};

static const struct watchdog_info ts4800_wdt_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE | WDIOF_KEEPALIVEPING,
	.identity = "TS-4800 Watchdog",
};

static int ts4800_wdt_probe(struct platform_device *pdev)
{
	struct device *dev = &pdev->dev;
	struct device_node *np = dev->of_node;
	struct device_node *syscon_np;
	struct watchdog_device *wdd;
	struct ts4800_wdt *wdt;
	u32 reg;
	int ret;

	syscon_np = of_parse_phandle(np, "syscon", 0);

Annotation

Implementation Notes