[PATCH linux dev-4.10 v3 3/4] watchdog: aspeed: Support configuration of external signal properties

[Andrew Jeffery]

Add support for configuring the drive strength and polarity on the
AST2500, and the pulse duration on both the AST2400 and AST2500.

Signed-off-by: Andrew Jeffery <andrew at aj.id.au>
---
 drivers/watchdog/aspeed_wdt.c | 42 ++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index d29f75e90bb6..334e43f0164b 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -42,6 +42,14 @@ MODULE_DEVICE_TABLE(of, aspeed_wdt_of_table);
 #define   WDT_CTRL_WDT_INTR		BIT(2)
 #define   WDT_CTRL_RESET_SYSTEM		BIT(1)
 #define   WDT_CTRL_ENABLE		BIT(0)
+#define WDT_RESET_WIDTH		0x18
+#define   WDT_RESET_WIDTH_ACTIVE_HIGH	BIT(31)
+#define     WDT_ACTIVE_HIGH_MAGIC	(0xA5 << 24)
+#define     WDT_ACTIVE_LOW_MAGIC	(0x5A << 24)
+#define   WDT_RESET_WIDTH_PUSH_PULL	BIT(30)
+#define     WDT_PUSH_PULL_MAGIC		(0xA8 << 24)
+#define     WDT_OPEN_DRAIN_MAGIC	(0x8A << 24)
+#define   WDT_RESET_WIDTH_DURATION	0xFFF
 
 #define WDT_RESTART_MAGIC	0x4755
 
@@ -152,6 +160,7 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	struct resource *res;
 	struct device_node *np;
 	const char *reset_type;
+	u32 duration;
 	int ret;
 
 	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
@@ -204,6 +213,39 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 		set_bit(WDOG_HW_RUNNING, &wdt->wdd.status);
 	}
 
+	if (of_device_is_compatible(np, "aspeed,ast2500-wdt")) {
+		u32 reg = readl(wdt->base + WDT_RESET_WIDTH);
+
+		reg &= WDT_RESET_WIDTH_DURATION;
+		if (of_property_read_bool(np, "aspeed,ext-push-pull"))
+			reg |= WDT_PUSH_PULL_MAGIC;
+		else
+			reg |= WDT_OPEN_DRAIN_MAGIC;
+
+		writel(reg, wdt->base + WDT_RESET_WIDTH);
+
+		reg &= WDT_RESET_WIDTH_DURATION;
+		if (of_property_read_bool(np, "aspeed,ext-active-high"))
+			reg |= WDT_ACTIVE_HIGH_MAGIC;
+		else
+			reg |= WDT_ACTIVE_LOW_MAGIC;
+
+		writel(reg, wdt->base + WDT_RESET_WIDTH);
+	}
+
+	if (!of_property_read_u32(np, "aspeed,ext-pulse-duration", &duration)) {
+		if (duration > WDT_RESET_WIDTH_DURATION) {
+			dev_err(&pdev->dev, "Invalid reset width\n");
+			return -EINVAL;
+		}
+
+		/*
+		 * The watchdog is always configured with a 1MHz source, so
+		 * there is no need to scale the microsecond value.
+		 */
+		writel(duration, wdt->base + WDT_RESET_WIDTH);
+	}
+
 	ret = watchdog_register_device(&wdt->wdd);
 	if (ret) {
 		dev_err(&pdev->dev, "failed to register\n");
-- 
2.11.0