[PATCH] hwrng: meson - Improve error handling for core clock

-ENOENT (ie. "there is no clock") is fine to ignore for an optional
clock, other values are not supposed to be ignored and should be
escalated to the caller (e.g. -EPROBE_DEFER). Ignore -ENOENT by using
devm_clk_get_optional().

While touching this code also add an error message for the fatal errors.

Signed-off-by: Uwe Kleine-König <redacted>
---
 drivers/char/hw_random/meson-rng.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/char/hw_random/meson-rng.c b/drivers/char/hw_random/meson-rng.c
index e446236e81f2..9f3e2eb8011d 100644
--- a/drivers/char/hw_random/meson-rng.c
+++ b/drivers/char/hw_random/meson-rng.c

@@ -54,9 +54,15 @@ static int meson_rng_probe(struct platform_device *pdev)
 	if (IS_ERR(data->base))
 		return PTR_ERR(data->base);
 
-	data->core_clk = devm_clk_get(dev, "core");
-	if (IS_ERR(data->core_clk))
-		data->core_clk = NULL;
+	data->core_clk = devm_clk_get_optional(dev, "core");
+	if (IS_ERR(data->core_clk)) {
+		ret = PTR_ERR(data->core_clk);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get core clock: %pe\n",
+				data->core_clk);
+
+		return ret;
+	}
 
 	if (data->core_clk) {
 		ret = clk_prepare_enable(data->core_clk);

-       data->core_clk = devm_clk_get(dev, "core");
-       if (IS_ERR(data->core_clk))
-               data->core_clk = NULL;
+       data->core_clk = devm_clk_get_optional(dev, "core");
+       if (IS_ERR(data->core_clk)) {
+               ret = PTR_ERR(data->core_clk);
+               if (ret != -EPROBE_DEFER)
+                       dev_err(dev, "Failed to get core clock: %pe\n",
+                               data->core_clk);
+
+               return ret;