watchdog: sp805_wdt: get platform clock from dt file

Get the watchdog platform clock from the DTS file
using clk subsystem and use the same for calculating
ticks in msec.
Signed-off-by: NRayagonda Kokatanur <rayagonda.kokatanur@broadcom.com>
Signed-off-by: NBharat Kumar Reddy Gooty <bharat.gooty@broadcom.com>
Reviewed-by: NStefan Roese <sr@denx.de>

drivers/watchdog/sp805_wdt.c

@@ -7,6 +7,7 @@
 
 #include <asm/io.h>
 #include <common.h>
+#include <clk.h>
 #include <dm/device.h>
 #include <dm/fdtaddr.h>
 #include <dm/read.h>
@@ -34,6 +35,7 @@ DECLARE_GLOBAL_DATA_PTR;
 
 struct sp805_wdt_priv {
 	void __iomem *reg;
+	unsigned long clk_rate;
 };
 
 static int sp805_wdt_reset(struct udevice *dev)
@@ -63,8 +65,13 @@ static int sp805_wdt_start(struct udevice *dev, u64 timeout, ulong flags)
 	 * set 120s, the gd->bus_clk is less than 1145MHz, the load_value will
 	 * not overflow.
 	 */
-	load_value = (gd->bus_clk) /
-		(2 * 1000 * SYS_FSL_WDT_CLK_DIV) * load_time;
+	if (gd->bus_clk) {
+		load_value = (gd->bus_clk) /
+			(2 * 1000 * SYS_FSL_WDT_CLK_DIV) * load_time;
+	} else {
+		/* platform provide clk */
+		load_value = (timeout / 2) * (priv->clk_rate / 1000);
+	}
 
 	writel(UNLOCK, priv->reg + WDTLOCK);
 	writel(load_value, priv->reg + WDTLOAD);
@@ -105,11 +112,15 @@ static int sp805_wdt_probe(struct udevice *dev)
 static int sp805_wdt_ofdata_to_platdata(struct udevice *dev)
 {
 	struct sp805_wdt_priv *priv = dev_get_priv(dev);
+	struct clk clk;
 
 	priv->reg = (void __iomem *)dev_read_addr(dev);
 	if (IS_ERR(priv->reg))
 		return PTR_ERR(priv->reg);
 
+	if (!clk_get_by_index(dev, 0, &clk))
+		priv->clk_rate = clk_get_rate(&clk);
+
 	return 0;
 }