feat(clk): add set_parent callback

This callback will be used to set a clock's parent if the underlying
clock driver supports this option.

Change-Id: Ie8a77d17dd3cc867bd520217b481cd188317a9c9
Signed-off-by: Ghennadi Procopciuc <ghennadi.procopciuc@nxp.com>

drivers/clk/clk.c

@@ -41,6 +41,13 @@ int clk_get_parent(unsigned long id)
 	return ops->get_parent(id);
 }
 
+int clk_set_parent(unsigned long id, unsigned long parent_id)
+{
+	assert((ops != NULL) && (ops->set_parent != NULL));
+
+	return ops->set_parent(id, parent_id);
+}
+
 bool clk_is_enabled(unsigned long id)
 {
 	assert((ops != NULL) && (ops->is_enabled != NULL));

include/drivers/clk.h

@@ -14,6 +14,7 @@ struct clk_ops {
 	void (*disable)(unsigned long id);
 	unsigned long (*get_rate)(unsigned long id);
 	int (*get_parent)(unsigned long id);
+	int (*set_parent)(unsigned long id, unsigned long parent_id);
 	bool (*is_enabled)(unsigned long id);
 };
 
@@ -22,6 +23,7 @@ void clk_disable(unsigned long id);
 unsigned long clk_get_rate(unsigned long id);
 bool clk_is_enabled(unsigned long id);
 int clk_get_parent(unsigned long id);
+int clk_set_parent(unsigned long id, unsigned long parent_id);
 
 void clk_register(const struct clk_ops *ops);