[PATCH] clk: ti: mux: resolve parent clocks by DT index, not by name

[PATCH] clk: ti: mux: resolve parent clocks by DT index, not by name

[Mathieu Dubois-Briand]

Resolve parent clocks by their index into the device tree "clocks"
property rather than matching names as strings. Name-based matching is
fragile because a clock's "clock-output-names" value in its provider
node can differ from the name used to reference it in a consumer node,
and because names must be globally unique across all clock providers.

On AM335x, this caused broken clock trees where some clocks failed to
enable because their parents could not be found.

Replace of_clk_parent_fill() with a clk_parent_data array that sets
.index to the array position.

Fixes: ec7aa25fa483 ("ARM: dts: Use clock-output-names for am3")
Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>
---
This commit aims to solve an issue I've been describing a few months ago
on AM335x SoC [1]. I believe using the parent_data field of
clk_init_data structure is now the preferred way to convey that data,
and it should be more reliable than string comparisons.

[1]: https://lore.kernel.org/all/DI4RUFQNSSNP.2QMSSQWJW9I2O@bootlin.com/
---
 drivers/clk/ti/mux.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/clk/ti/mux.c b/drivers/clk/ti/mux.c
index d6a0ccfd81db..ded4432f7528 100644
--- a/drivers/clk/ti/mux.c
+++ b/drivers/clk/ti/mux.c
@@ -119,7 +119,7 @@ const struct clk_ops ti_clk_mux_ops = {
 };
 
 static struct clk *_register_mux(struct device_node *node, const char *name,
-				 const char * const *parent_names,
+				 const struct clk_parent_data *parent_data,
 				 u8 num_parents, unsigned long flags,
 				 struct clk_omap_reg *reg, u8 shift, u32 mask,
 				 s8 latch, u8 clk_mux_flags, u32 *table)
@@ -136,7 +136,7 @@ static struct clk *_register_mux(struct device_node *node, const char *name,
 	init.name = name;
 	init.ops = &ti_clk_mux_ops;
 	init.flags = flags;
-	init.parent_names = parent_names;
+	init.parent_data = parent_data;
 	init.num_parents = num_parents;
 
 	/* struct clk_mux assignments */
@@ -167,24 +167,26 @@ static void of_mux_clk_setup(struct device_node *node)
 	struct clk *clk;
 	struct clk_omap_reg reg;
 	unsigned int num_parents;
-	const char **parent_names;
+	struct clk_parent_data *parent_data;
 	const char *name;
 	u8 clk_mux_flags = 0;
 	u32 mask = 0;
 	u32 shift = 0;
 	s32 latch = -EINVAL;
 	u32 flags = CLK_SET_RATE_NO_REPARENT;
+	int i;
 
 	num_parents = of_clk_get_parent_count(node);
 	if (num_parents < 2) {
 		pr_err("mux-clock %pOFn must have parents\n", node);
 		return;
 	}
-	parent_names = kcalloc(num_parents, sizeof(char *), GFP_KERNEL);
-	if (!parent_names)
-		goto cleanup;
+	parent_data = kcalloc(num_parents, sizeof(*parent_data), GFP_KERNEL);
+	if (!parent_data)
+		return;
 
-	of_clk_parent_fill(node, parent_names, num_parents);
+	for (i = 0; i < num_parents; i++)
+		parent_data[i].index = i;
 
 	if (ti_clk_get_reg_addr(node, 0, &reg))
 		goto cleanup;
@@ -207,7 +209,7 @@ static void of_mux_clk_setup(struct device_node *node)
 	mask = (1 << fls(mask)) - 1;
 
 	name = ti_dt_clk_name(node);
-	clk = _register_mux(node, name, parent_names, num_parents,
+	clk = _register_mux(node, name, parent_data, num_parents,
 			    flags, &reg, shift, mask, latch, clk_mux_flags,
 			    NULL);
 
@@ -215,7 +217,7 @@ static void of_mux_clk_setup(struct device_node *node)
 		of_clk_add_provider(node, of_clk_src_simple_get, clk);
 
 cleanup:
-	kfree(parent_names);
+	kfree(parent_data);
 }
 CLK_OF_DECLARE(mux_clk, "ti,mux-clock", of_mux_clk_setup);
 

---
base-commit: a13c140cc289c0b7b3770bce5b3ad42ab35074aa
change-id: 20260713-mathieu-wdt-clock-theo-f0c5ba58e258

Best regards,
-- 
Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>

Re: [PATCH] clk: ti: mux: resolve parent clocks by DT index, not by name

[Brian Masney]

Hi Mathieu,

On Wed, Jul 15, 2026 at 05:09:56PM +0200, Mathieu Dubois-Briand wrote:
> Resolve parent clocks by their index into the device tree "clocks"
> property rather than matching names as strings. Name-based matching is
> fragile because a clock's "clock-output-names" value in its provider
> node can differ from the name used to reference it in a consumer node,
> and because names must be globally unique across all clock providers.
> 
> On AM335x, this caused broken clock trees where some clocks failed to
> enable because their parents could not be found.
> 
> Replace of_clk_parent_fill() with a clk_parent_data array that sets
> .index to the array position.
> 
> Fixes: ec7aa25fa483 ("ARM: dts: Use clock-output-names for am3")
> Signed-off-by: Mathieu Dubois-Briand <mathieu.dubois-briand@bootlin.com>

So this only updates of_mux_clk_setup(). of_ti_composite_mux_clk_setup()
calls ti_clk_add_component(), which does a name based matching as well.
It would be nice to have this consistent within the same driver. I know
this is going to require a larger refactor.

Otherwise your fix looks correct to me.

Brian