clk: Return errors from clk providers in __of_clk_get_from_provider()

Before commit 0861e5b8cf80 (clk: Add clk_hw OF clk providers,
2016-02-05) __of_clk_get_from_provider() would return an error
pointer of the provider's choosing if there was a provider
registered and EPROBE_DEFER otherwise. After that commit, it
would return EPROBE_DEFER regardless of whether or not the
provider returned an error. This is odd and can lead to behavior
where clk consumers keep probe deferring when they should be
seeing some other error.

Let's restore the previous behavior where we only return
EPROBE_DEFER when there isn't a provider in our of_clk_providers
list. Otherwise, return the error from the last provider we find
that matches the node.

Reported-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Fixes: 0861e5b8cf80 ("clk: Add clk_hw OF clk providers")
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

drivers/clk/clk.c

@@ -3194,7 +3194,7 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 {
 	struct of_clk_provider *provider;
 	struct clk *clk = ERR_PTR(-EPROBE_DEFER);
-	struct clk_hw *hw = ERR_PTR(-EPROBE_DEFER);
+	struct clk_hw *hw;
 
 	if (!clkspec)
 		return ERR_PTR(-EINVAL);
@@ -3202,12 +3202,13 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 	/* Check if we have such a provider in our array */
 	mutex_lock(&of_clk_mutex);
 	list_for_each_entry(provider, &of_clk_providers, link) {
-		if (provider->node == clkspec->np)
+		if (provider->node == clkspec->np) {
 			hw = __of_clk_get_hw_from_provider(provider, clkspec);
-		if (!IS_ERR(hw)) {
 			clk = __clk_create_clk(hw, dev_id, con_id);
+		}
 
-			if (!IS_ERR(clk) && !__clk_get(clk)) {
+		if (!IS_ERR(clk)) {
+			if (!__clk_get(clk)) {
 				__clk_free_clk(clk);
 				clk = ERR_PTR(-ENOENT);
 			}