drivers/watchdog/menz69_wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/menz69_wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/menz69_wdt.c
Extension
.c
Size
4051 bytes
Lines
167
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 men_z069_drv {
	struct watchdog_device wdt;
	void __iomem *base;
	struct resource *mem;
};

#define MEN_Z069_WTR			0x10
#define MEN_Z069_WTR_WDEN		BIT(15)
#define MEN_Z069_WTR_WDET_MASK		0x7fff
#define MEN_Z069_WVR			0x14

#define MEN_Z069_TIMER_FREQ		500 /* 500 Hz */
#define MEN_Z069_WDT_COUNTER_MIN	1
#define MEN_Z069_WDT_COUNTER_MAX	0x7fff
#define MEN_Z069_DEFAULT_TIMEOUT	30

static bool nowayout = WATCHDOG_NOWAYOUT;
module_param(nowayout, bool, 0);
MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
			    __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");

static int men_z069_wdt_start(struct watchdog_device *wdt)
{
	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
	u16 val;

	val = readw(drv->base + MEN_Z069_WTR);
	val |= MEN_Z069_WTR_WDEN;
	writew(val, drv->base + MEN_Z069_WTR);

	return 0;
}

static int men_z069_wdt_stop(struct watchdog_device *wdt)
{
	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
	u16 val;

	val = readw(drv->base + MEN_Z069_WTR);
	val &= ~MEN_Z069_WTR_WDEN;
	writew(val, drv->base + MEN_Z069_WTR);

	return 0;
}

static int men_z069_wdt_ping(struct watchdog_device *wdt)
{
	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
	u16 val;

	/* The watchdog trigger value toggles between 0x5555 and 0xaaaa */
	val = readw(drv->base + MEN_Z069_WVR);
	val ^= 0xffff;
	writew(val, drv->base + MEN_Z069_WVR);

	return 0;
}

static int men_z069_wdt_set_timeout(struct watchdog_device *wdt,
				    unsigned int timeout)
{
	struct men_z069_drv *drv = watchdog_get_drvdata(wdt);
	u16 reg, val, ena;

	wdt->timeout = timeout;
	val = timeout * MEN_Z069_TIMER_FREQ;

	reg = readw(drv->base + MEN_Z069_WTR);
	ena = reg & MEN_Z069_WTR_WDEN;
	reg = ena | val;
	writew(reg, drv->base + MEN_Z069_WTR);

	return 0;
}

static const struct watchdog_info men_z069_info = {
	.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
	.identity = "MEN z069 Watchdog",
};

static const struct watchdog_ops men_z069_ops = {
	.owner = THIS_MODULE,
	.start = men_z069_wdt_start,
	.stop = men_z069_wdt_stop,
	.ping = men_z069_wdt_ping,
	.set_timeout = men_z069_wdt_set_timeout,
};

static int men_z069_probe(struct mcb_device *dev,
			  const struct mcb_device_id *id)

Annotation

Implementation Notes