watchdog: sp805: Add clock-frequency property

Use clock-frequency property given in _DSD object
of ACPI device to calculate Watchdog rate as binding
clock devices are not available as device tree.

Note: There is no formal review process for _DSD
properties
Signed-off-by: Srinath Mannam <srinath.mannam@broadcom.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Ray Jui <ray.jui@broadcom.com>
Reviewed-by: Scott Branden <scott.branden@broadcom.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/sp805_wdt.c

@@ -11,6 +11,7 @@
  * warranty of any kind, whether express or implied.
  */
 
+#include <linux/acpi.h>
 #include <linux/device.h>
 #include <linux/resource.h>
 #include <linux/amba/bus.h>
@@ -22,6 +23,7 @@
 #include <linux/math64.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
+#include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
@@ -66,6 +68,7 @@ struct sp805_wdt {
 	spinlock_t			lock;
 	void __iomem			*base;
 	struct clk			*clk;
+	u64				rate;
 	struct amba_device		*adev;
 	unsigned int			load_val;
 };
@@ -90,7 +93,7 @@ static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
 	struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
 	u64 load, rate;
 
-	rate = clk_get_rate(wdt->clk);
+	rate = wdt->rate;
 
 	/*
 	 * sp805 runs counter with given value twice, after the end of first
@@ -116,9 +119,7 @@ static int wdt_setload(struct watchdog_device *wdd, unsigned int timeout)
 static unsigned int wdt_timeleft(struct watchdog_device *wdd)
 {
 	struct sp805_wdt *wdt = watchdog_get_drvdata(wdd);
-	u64 load, rate;
-
-	rate = clk_get_rate(wdt->clk);
+	u64 load;
 
 	spin_lock(&wdt->lock);
 	load = readl_relaxed(wdt->base + WDTVALUE);
@@ -128,7 +129,7 @@ static unsigned int wdt_timeleft(struct watchdog_device *wdd)
 		load += wdt->load_val + 1;
 	spin_unlock(&wdt->lock);
 
-	return div_u64(load, rate);
+	return div_u64(load, wdt->rate);
 }
 
 static int
@@ -238,11 +239,25 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
-	wdt->clk = devm_clk_get(&adev->dev, NULL);
-	if (IS_ERR(wdt->clk)) {
-		dev_warn(&adev->dev, "Clock not found\n");
-		ret = PTR_ERR(wdt->clk);
-		goto err;
+	if (adev->dev.of_node) {
+		wdt->clk = devm_clk_get(&adev->dev, NULL);
+		if (IS_ERR(wdt->clk)) {
+			dev_err(&adev->dev, "Clock not found\n");
+			return PTR_ERR(wdt->clk);
+		}
+		wdt->rate = clk_get_rate(wdt->clk);
+	} else if (has_acpi_companion(&adev->dev)) {
+		/*
+		 * When Driver probe with ACPI device, clock devices
+		 * are not available, so watchdog rate get from
+		 * clock-frequency property given in _DSD object.
+		 */
+		device_property_read_u64(&adev->dev, "clock-frequency",
+					 &wdt->rate);
+		if (!wdt->rate) {
+			dev_err(&adev->dev, "no clock-frequency property\n");
+			return -ENODEV;
+		}
 	}
 
 	wdt->adev = adev;