clk: Introduce clk_core_has_parent()

We will need to know if a clk_core pointer has a given parent in other
functions, so let's create a clk_core_has_parent() function that
clk_has_parent() will call into.

For good measure, let's add some unit tests as well to make sure it
works properly.

Tested-by: Alexander Stein <alexander.stein@ew.tq-group.com> # imx8mp
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com> # exynos4210, meson g12b
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20220816112530.1837489-20-maxime@cerno.tech
Tested-by: Linux Kernel Functional Testing <lkft@linaro.org>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
[sboyd@kernel.org: Move tmp declaration, fix conditional to check for
current parent]
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 22 insertions, 15 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f8a8bdd552d6..8e4a8b9aa320 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -539,6 +539,27 @@ static bool mux_is_better_rate(unsigned long rate, unsigned long now,
 static int clk_core_round_rate_nolock(struct clk_core *core,
 				      struct clk_rate_request *req);
 
+static bool clk_core_has_parent(struct clk_core *core, const struct clk_core *parent)
+{
+	struct clk_core *tmp;
+	unsigned int i;
+
+	/* Optimize for the case where the parent is already the parent. */
+	if (core->parent == parent)
+		return true;
+
+	for (i = 0; i < core->num_parents; i++) {
+		tmp = clk_core_get_parent_by_index(core, i);
+		if (!tmp)
+			continue;
+
+		if (tmp == parent)
+			return true;
+	}
+
+	return false;
+}
+
 int clk_mux_determine_rate_flags(struct clk_hw *hw,
 				 struct clk_rate_request *req,
 				 unsigned long flags)
@@ -2574,25 +2595,11 @@ void clk_hw_reparent(struct clk_hw *hw, struct clk_hw *new_parent)
  */
 bool clk_has_parent(struct clk *clk, struct clk *parent)
 {
-	struct clk_core *core, *parent_core;
-	int i;
-
 	/* NULL clocks should be nops, so return success if either is NULL. */
 	if (!clk || !parent)
 		return true;
 
-	core = clk->core;
-	parent_core = parent->core;
-
-	/* Optimize for the case where the parent is already the parent. */
-	if (core->parent == parent_core)
-		return true;
-
-	for (i = 0; i < core->num_parents; i++)
-		if (!strcmp(core->parents[i].name, parent_core->name))
-			return true;
-
-	return false;
+	return clk_core_has_parent(clk->core, parent->core);
 }
 EXPORT_SYMBOL_GPL(clk_has_parent);