drivers/watchdog/rn5t618_wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/rn5t618_wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/rn5t618_wdt.c
Extension
.c
Size
5179 bytes
Lines
197
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 rn5t618_wdt {
	struct watchdog_device wdt_dev;
	struct rn5t618 *rn5t618;
};

/*
 * This array encodes the values of WDOGTIM field for the supported
 * watchdog expiration times. If the watchdog is not accessed before
 * the timer expiration, the PMU generates an interrupt and if the CPU
 * doesn't clear it within one second the system is restarted.
 */
static const struct {
	u8 reg_val;
	unsigned int time;
} rn5t618_wdt_map[] = {
	{ 0, 1 },
	{ 1, 8 },
	{ 2, 32 },
	{ 3, 128 },
};

static int rn5t618_wdt_set_timeout(struct watchdog_device *wdt_dev,
				   unsigned int t)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
	int ret, i;

	for (i = 0; i < ARRAY_SIZE(rn5t618_wdt_map); i++) {
		if (rn5t618_wdt_map[i].time + 1 >= t)
			break;
	}

	if (i == ARRAY_SIZE(rn5t618_wdt_map))
		return -EINVAL;

	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
				 RN5T618_WATCHDOG_WDOGTIM_M,
				 rn5t618_wdt_map[i].reg_val);
	if (!ret)
		wdt_dev->timeout = rn5t618_wdt_map[i].time;

	return ret;
}

static int rn5t618_wdt_start(struct watchdog_device *wdt_dev)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
	int ret;

	ret = rn5t618_wdt_set_timeout(wdt_dev, wdt_dev->timeout);
	if (ret)
		return ret;

	/* enable repower-on */
	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_REPCNT,
				 RN5T618_REPCNT_REPWRON,
				 RN5T618_REPCNT_REPWRON);
	if (ret)
		return ret;

	/* enable watchdog */
	ret = regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
				 RN5T618_WATCHDOG_WDOGEN,
				 RN5T618_WATCHDOG_WDOGEN);
	if (ret)
		return ret;

	/* enable watchdog interrupt */
	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_PWRIREN,
				  RN5T618_PWRIRQ_IR_WDOG,
				  RN5T618_PWRIRQ_IR_WDOG);
}

static int rn5t618_wdt_stop(struct watchdog_device *wdt_dev)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);

	return regmap_update_bits(wdt->rn5t618->regmap, RN5T618_WATCHDOG,
				  RN5T618_WATCHDOG_WDOGEN, 0);
}

static int rn5t618_wdt_ping(struct watchdog_device *wdt_dev)
{
	struct rn5t618_wdt *wdt = watchdog_get_drvdata(wdt_dev);
	unsigned int val;
	int ret;

	/* The counter is restarted after a R/W access to watchdog register */
	ret = regmap_read(wdt->rn5t618->regmap, RN5T618_WATCHDOG, &val);
	if (ret)

Annotation

Implementation Notes