drivers/watchdog/rzg2l_wdt.c

Source file repositories/reference/linux-study-clean/drivers/watchdog/rzg2l_wdt.c

File Facts

System
Linux kernel
Corpus path
drivers/watchdog/rzg2l_wdt.c
Extension
.c
Size
9363 bytes
Lines
360
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 rzg2l_wdt_priv {
	void __iomem *base;
	struct watchdog_device wdev;
	struct reset_control *rstc;
	unsigned long osc_clk_rate;
	unsigned long delay;
	struct clk *pclk;
	struct clk *osc_clk;
	enum rz_wdt_type devtype;
};

static void rzg2l_wdt_wait_delay(struct rzg2l_wdt_priv *priv)
{
	/* delay timer when change the setting register */
	ndelay(priv->delay);
}

static u32 rzg2l_wdt_get_cycle_usec(unsigned long cycle, u32 wdttime)
{
	u64 timer_cycle_us = 1024 * 1024ULL * (wdttime + 1) * MICRO;

	return div64_ul(timer_cycle_us, cycle);
}

static void rzg2l_wdt_write(struct rzg2l_wdt_priv *priv, u32 val, unsigned int reg)
{
	if (reg == WDTSET)
		val &= WDTSET_COUNTER_MASK;

	writel_relaxed(val, priv->base + reg);
	/* Registers other than the WDTINT is always synchronized with WDT_CLK */
	if (reg != WDTINT)
		rzg2l_wdt_wait_delay(priv);
}

static void rzg2l_wdt_init_timeout(struct watchdog_device *wdev)
{
	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
	u32 time_out;

	/* Clear Lapsed Time Register and clear Interrupt */
	rzg2l_wdt_write(priv, WDTINT_INTDISP, WDTINT);
	/* 2 consecutive overflow cycle needed to trigger reset */
	time_out = (wdev->timeout * (MICRO / 2)) /
		   rzg2l_wdt_get_cycle_usec(priv->osc_clk_rate, 0);
	rzg2l_wdt_write(priv, WDTSET_COUNTER_VAL(time_out), WDTSET);
}

static int rzg2l_wdt_start(struct watchdog_device *wdev)
{
	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
	int ret;

	ret = pm_runtime_resume_and_get(wdev->parent);
	if (ret)
		return ret;

	ret = reset_control_deassert(priv->rstc);
	if (ret) {
		pm_runtime_put(wdev->parent);
		return ret;
	}

	/* Initialize time out */
	rzg2l_wdt_init_timeout(wdev);

	/* Initialize watchdog counter register */
	rzg2l_wdt_write(priv, 0, WDTTIM);

	/* Enable watchdog timer*/
	rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT);

	return 0;
}

static int rzg2l_wdt_stop(struct watchdog_device *wdev)
{
	struct rzg2l_wdt_priv *priv = watchdog_get_drvdata(wdev);
	int ret;

	ret = reset_control_assert(priv->rstc);
	if (ret)
		return ret;

	pm_runtime_put(wdev->parent);

	return 0;
}

static int rzg2l_wdt_set_timeout(struct watchdog_device *wdev, unsigned int timeout)

Annotation

Implementation Notes