clk: Warn about critical clks that fail to enable

If we don't warn here users of the CLK_IS_CRITICAL flag may not know
that their clk isn't actually enabled because it silently fails to
enable. Let's print a warning in that case so developers find these
problems faster.

Suggested-by: Jerome Brunet <jbrunet@baylibre.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Link: https://lkml.kernel.org/r/20200102005503.71923-1-sboyd@kernel.org
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>

drivers/clk/clk.c

@@ -3427,13 +3427,18 @@ static int __clk_core_init(struct clk_core *core)
 		unsigned long flags;
 
 		ret = clk_core_prepare(core);
-		if (ret)
+		if (ret) {
+			pr_warn("%s: critical clk '%s' failed to prepare\n",
+			       __func__, core->name);
 			goto out;
+		}
 
 		flags = clk_enable_lock();
 		ret = clk_core_enable(core);
 		clk_enable_unlock(flags);
 		if (ret) {
+			pr_warn("%s: critical clk '%s' failed to enable\n",
+			       __func__, core->name);
 			clk_core_unprepare(core);
 			goto out;
 		}