clk: Make of_clk_get_parent_count() return unsigned ints

Russell King recently pointed out a bug in the clk-gpio code
where it fails to register the clk if of_clk_get_parent_count()
returns an error because the "clocks" property isn't present in
the DT node. If we're trying to count parents from DT we'd like
to know the count, not if there is a "clocks" property or not.
Furthermore, some drivers are assigning the return value to their
clk_init_data::num_parents member which is unsigned, leading to
potentially large numbers of parents when the property isn't
present.

Let's change the API to return an unsigned int instead of an int.
All the callers just want to know the count anyway, and this
avoids the bug that was in the clk-gpio driver.

Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index b775c88ac36ded85bf41d6e6e2070929d4b8e325..fb74dc1f7520503d72f024b596dc72d002851e4c 100644 (file)
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -2986,9 +2986,21 @@ struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 }
 EXPORT_SYMBOL_GPL(of_clk_get_from_provider);
 
-int of_clk_get_parent_count(struct device_node *np)
+/**
+ * of_clk_get_parent_count() - Count the number of clocks a device node has
+ * @np: device node to count
+ *
+ * Returns: The number of clocks that are possible parents of this node
+ */
+unsigned int of_clk_get_parent_count(struct device_node *np)
 {
-       return of_count_phandle_with_args(np, "clocks", "#clock-cells");
+       int count;
+
+       count = of_count_phandle_with_args(np, "clocks", "#clock-cells");
+       if (count < 0)
+               return 0;
+
+       return count;
 }
 EXPORT_SYMBOL_GPL(of_clk_get_parent_count);
 

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index fce7f027f8a77a15aacc6892d08c9509defeab19..da95258127aace556dc32810c0b483bcda95198f 100644 (file)
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -716,7 +716,7 @@ void of_clk_del_provider(struct device_node *np);
 struct clk *of_clk_src_simple_get(struct of_phandle_args *clkspec,
                                  void *data);
 struct clk *of_clk_src_onecell_get(struct of_phandle_args *clkspec, void *data);
-int of_clk_get_parent_count(struct device_node *np);
+unsigned int of_clk_get_parent_count(struct device_node *np);
 int of_clk_parent_fill(struct device_node *np, const char **parents,
                       unsigned int size);
 const char *of_clk_get_parent_name(struct device_node *np, int index);