clk: add clk_is_orphan() to check if a clocks inherits from an orphan clock
From: Heiko Stuebner <heiko@...> Date: Tue, 17 Feb 2015 23:22:03 +0100
Commit-Message
There are cases where it is helpful to know if the full clock path can be trusted or if there is a parent clock missing somewhere in the parent-path. We keep it confined to the ccf area for now, if later users outside the ccf surface it can be made more publically available. Signed-off-by: Heiko Stuebner <heiko@...>
Patch-Comment
drivers/clk/clk.c | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+)
Statistics
- 38 lines added
- 0 lines removed
Changes
------------------------------ drivers/clk/clk.c -------------------------------
index 512323f..476f491 100644
@@ -2271,6 +2271,44 @@ bool clk_is_match(const struct clk *p, const struct clk *q)
EXPORT_SYMBOL_GPL(clk_is_match);
/**
+ * __clk_is_orphan - check if a clock or its parent is an orphan
+ *
+ * Walks up the clock parents until it reaches a root-clock or
+ * a clock contained in the orphan list. Returns true if there is
+ * an orphan in the parent-path otherwise false.
+ */
+static bool __clk_is_orphan(struct clk_core *clk)
+{
+ struct clk_core *orphan;
+
+ if (clk->flags & CLK_IS_ROOT)
+ return false;
+
+ hlist_for_each_entry(orphan, &clk_orphan_list, child_node) {
+ if (clk == orphan)
+ return true;
+ }
+
+ if (clk->num_parents)
+ return __clk_is_orphan(clk->parent);
+
+ return false;
+}
+
+static bool clk_is_orphan(struct clk *clk)
+{
+ bool ret;
+
+ if (!clk)
+ return false;
+
+ clk_prepare_lock();
+ ret = __clk_is_orphan(clk->core);
+ clk_prepare_unlock();
+ return ret;
+}
+
+/**
* __clk_init - initialize the data structures in a struct clk
* @dev: device initializing this clk, placeholder for now
* @clk: clk being initialized