watchdog: sp805: Use devm_clk_get_optional()

Replace open coded variants of devm_clk_get_optional().

While at it, drop unneeded OF and ACPI dependency as the APIs in use
are provider agnostic.

Cc: Srinath Mannam <srinath.mannam@broadcom.com>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Srinath Mannam <srinath.mannam@broadcom.com>
Link: https://lore.kernel.org/r/20210517174456.22050-1-andriy.shevchenko@linux.intel.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

@@ -11,7 +11,6 @@
  * 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>
@@ -23,8 +22,8 @@
 #include <linux/math64.h>
 #include <linux/module.h>
 #include <linux/moduleparam.h>
-#include <linux/of.h>
 #include <linux/pm.h>
+#include <linux/property.h>
 #include <linux/slab.h>
 #include <linux/spinlock.h>
 #include <linux/types.h>
@@ -231,6 +230,7 @@ static int
 sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
 {
 	struct sp805_wdt *wdt;
+	u64 rate = 0;
 	int ret = 0;
 
 	wdt = devm_kzalloc(&adev->dev, sizeof(*wdt), GFP_KERNEL);
@@ -243,25 +243,23 @@ sp805_wdt_probe(struct amba_device *adev, const struct amba_id *id)
 	if (IS_ERR(wdt->base))
 		return PTR_ERR(wdt->base);
 
-	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;
-		}
+	/*
+	 * 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", &rate);
+
+	wdt->clk = devm_clk_get_optional(&adev->dev, NULL);
+	if (IS_ERR(wdt->clk))
+		return dev_err_probe(&adev->dev, PTR_ERR(wdt->clk), "Clock not found\n");
+
+	wdt->rate = clk_get_rate(wdt->clk);
+	if (!wdt->rate)
+		wdt->rate = rate;
+	if (!wdt->rate) {
+		dev_err(&adev->dev, "no clock-frequency property\n");
+		return -ENODEV;
 	}
 
 	wdt->adev = adev;