[PATCH v4 0/7] clk: Add support for clock nexus

[PATCH v4 0/7] clk: Add support for clock nexus

[Miquel Raynal (Schneider Electric)]

Adding support for clock nexus had some prerequisites requested by
Stephen, such as adding new selftests, the initial discussions come
from:

Link: https://lore.kernel.org/linux-clk/20260129201003.288605-1-miquel.raynal@bootlin.com/

Changes in v4:
- Fixed the kernel doc of of_find_node_by_name_kunit() which was lacking
  the fact that it could return NULL upon lookup failure. Also improved
  the commit message by mentioning the addition of that helper.
- All other Sashiko reports have either been disregarded because they
  were way too unrelated or just not relevant enough in my opinion.
- Link to v3: https://lore.kernel.org/r/20260716-schneider-v7-2-rc1-eip201-upstream-v3-0-98454e83845c@bootlin.com

Changes in v3:
- Prevent out-of-bounds clock-ranges fallback in of_parse_clkspec()
- tests: Check of_clk_add_hw_provider_kunit() return value and fix node
  ref leaks
- Link to v2: https://lore.kernel.org/r/20260710-schneider-v7-2-rc1-eip201-upstream-v2-0-b4680787377e@bootlin.com

Changes in v2:
- Collected tags.
- Rebased on top of v7.2-rc1
- Exported (test) clock symbols using the _IF_KUNIT() variant, and
  imported the NS in the test file.
- Fixed a leaking node reported by Brian in the tests. Also used
  existing helpers to simplify the test implementation as he wisely
  suggested.
- Reworded the nexus node binding description as suggested by Stephen.
- Dropped redundant and non restraining properties from the Nexus
  node as suggested by Rob.
- Assigned clock/clock-rate properties now traverse Nexus nodes.
- Rename helpers following Stephen proposals.
- Rework tests following Stephen hints.
- Link to v1: https://lore.kernel.org/r/20260327-schneider-v7-0-rc1-crypto-v1-0-5e6ff7853994@bootlin.com

Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
---
Miquel Raynal (Schneider Electric) (7):
      dt-bindings: clock: Introduce nexus nodes
      clk: tests: Add clk_parse_clkspec() Kunit testing
      clk: tests: Add Kunit testing for of_clk_get_parent_name()
      clk: Improve a couple of comments
      clk: Use the generic OF phandle parsing in only one place
      clk: Add support for clock nexus dt bindings
      clk: tests: Add Kunit testing for nexus nodes

 .../bindings/clock/clock-nexus-node.yaml           |  30 +++++
 drivers/clk/Makefile                               |   1 +
 drivers/clk/clk-conf.c                             |  12 +-
 drivers/clk/clk.c                                  |  15 ++-
 drivers/clk/clk_kunit_helpers.c                    |  31 +++++
 drivers/clk/clk_test.c                             | 139 +++++++++++++++++++++
 drivers/clk/kunit_clk_parse_clkspec.dtso           |  31 +++++
 include/kunit/clk.h                                |   2 +
 8 files changed, 249 insertions(+), 12 deletions(-)
---
base-commit: 7f26e010764df304602f33912a0550dcf46e72c2
change-id: 20260710-schneider-v7-2-rc1-eip201-upstream-a470e5eab92d

Best regards,
-- 
Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>

[PATCH v4 1/7] dt-bindings: clock: Introduce nexus nodes

[Miquel Raynal (Schneider Electric)]

Hardware containers can just decouple external resources like clock
without any more control. Nexus nodes already exist for PWM and GPIOs,
add a binding to allow them for clocks as well.

No examples are given, the file is litteraly a copy-paste from Hervé
Codina's work on PWM Nexus nodes, hence we just point to the examples
there which already illustrate very clearly the concept of the various
properties.

Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
---
 .../bindings/clock/clock-nexus-node.yaml           | 30 ++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/Documentation/devicetree/bindings/clock/clock-nexus-node.yaml b/Documentation/devicetree/bindings/clock/clock-nexus-node.yaml
new file mode 100644
index 000000000000..ff3283bd5fb1
--- /dev/null
+++ b/Documentation/devicetree/bindings/clock/clock-nexus-node.yaml
@@ -0,0 +1,30 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/clock/clock-nexus-node.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Clock Nexus
+
+description: >
+  A nexus node allows to remap a clock specifier list in a consumer node
+  through a container or a connector node in a generic way. With this
+  remapping, the consumer node needs to know only about the nexus
+  node. Resources behind the nexus node are decoupled by the nexus node
+  itself.
+
+maintainers:
+  - Miquel Raynal <miquel.raynal@bootlin.com>
+
+select: true
+
+properties:
+  clock-map:
+    $ref: /schemas/types.yaml#/definitions/uint32-matrix
+
+dependentRequired:
+  clock-map: ['#clock-cells']
+
+additionalProperties: true
+
+# See the original pwm-nexus-node.yaml description for examples

-- 
2.54.0

[PATCH v4 2/7] clk: tests: Add clk_parse_clkspec() Kunit testing

[Miquel Raynal (Schneider Electric)]

Create a new set of kunit tests to make sure clk_parse_clkspec() is
working as expected. We currently verify if we get a proper device when
using indexes and names. If we make an out of bounds request we expect
an error.

For testing purposes, we must ensure of_clk_get_hw()'s symbol is
exported.

Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
---
 drivers/clk/Makefile                     |   1 +
 drivers/clk/clk.c                        |   2 +
 drivers/clk/clk_test.c                   | 110 +++++++++++++++++++++++++++++++
 drivers/clk/kunit_clk_parse_clkspec.dtso |  21 ++++++
 4 files changed, 134 insertions(+)

diff --git a/drivers/clk/Makefile b/drivers/clk/Makefile
index cc108a75a900..035b984db70d 100644
--- a/drivers/clk/Makefile
+++ b/drivers/clk/Makefile
@@ -19,6 +19,7 @@ clk-test-y			:= clk_test.o \
 				   kunit_clk_assigned_rates_zero.dtbo.o \
 				   kunit_clk_assigned_rates_zero_consumer.dtbo.o \
 				   kunit_clk_hw_get_dev_of_node.dtbo.o \
+				   kunit_clk_parse_clkspec.dtbo.o \
 				   kunit_clk_parent_data_test.dtbo.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-divider.o
 obj-$(CONFIG_COMMON_CLK)	+= clk-fixed-factor.o
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 048adfa86a5d..08874cf9b561 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -24,6 +24,7 @@
 #include <linux/spinlock.h>
 #include <linux/string.h>
 #include <linux/stringhash.h>
+#include <kunit/visibility.h>
 
 #include "clk.h"
 
@@ -5300,6 +5301,7 @@ struct clk_hw *of_clk_get_hw(struct device_node *np, int index,
 
 	return hw;
 }
+EXPORT_SYMBOL_IF_KUNIT(of_clk_get_hw);
 
 static struct clk *__of_clk_get(struct device_node *np,
 				int index, const char *dev_id,
diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index b1961daac5e2..f47f81b7d72a 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -3541,10 +3541,119 @@ static struct kunit_suite clk_hw_get_dev_of_node_test_suite = {
 	.test_cases = clk_hw_get_dev_of_node_test_cases,
 };
 
+static const struct clk_init_data clk_parse_clkspec_1_init_data = {
+	.name = "clk_parse_clkspec_1",
+	.ops = &empty_clk_ops,
+};
+
+static const struct clk_init_data clk_parse_clkspec_2_init_data = {
+	.name = "clk_parse_clkspec_2",
+	.ops = &empty_clk_ops,
+};
+
+struct clk_parse_clkspec_ctx {
+	struct device_node *cons_np;
+};
+
+static int clk_parse_clkspec_init(struct kunit *test)
+{
+	struct device_node *prov1_np, *prov2_np;
+	struct clk_parse_clkspec_ctx *ctx;
+	struct clk_hw *hw1, *hw2;
+
+	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
+	test->priv = ctx;
+
+	KUNIT_ASSERT_EQ(test, 0, of_overlay_apply_kunit(test, kunit_clk_parse_clkspec));
+
+	/* Register provider 1 */
+	hw1 = kunit_kzalloc(test, sizeof(*hw1), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, hw1);
+	hw1->init = &clk_parse_clkspec_1_init_data;
+
+	prov1_np = of_find_compatible_node(NULL, NULL, "test,clock-provider1");
+	KUNIT_ASSERT_NOT_NULL(test, prov1_np);
+	of_node_put_kunit(test, prov1_np);
+
+	KUNIT_ASSERT_EQ(test, 0, of_clk_hw_register_kunit(test, prov1_np, hw1));
+	KUNIT_ASSERT_EQ(test, 0, of_clk_add_hw_provider_kunit(test, prov1_np, of_clk_hw_simple_get, hw1));
+
+	/* Register provider 2 */
+	hw2 = kunit_kzalloc(test, sizeof(*hw2), GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, hw2);
+	hw2->init = &clk_parse_clkspec_2_init_data;
+
+	prov2_np = of_find_compatible_node(NULL, NULL, "test,clock-provider2");
+	KUNIT_ASSERT_NOT_NULL(test, prov2_np);
+	of_node_put_kunit(test, prov2_np);
+
+	KUNIT_ASSERT_EQ(test, 0, of_clk_hw_register_kunit(test, prov2_np, hw2));
+	KUNIT_ASSERT_EQ(test, 0, of_clk_add_hw_provider_kunit(test, prov2_np, of_clk_hw_simple_get, hw2));
+
+	ctx->cons_np = of_find_compatible_node(NULL, NULL, "test,clock-consumer");
+	KUNIT_ASSERT_NOT_NULL(test, ctx->cons_np);
+	of_node_put_kunit(test, ctx->cons_np);
+
+	return 0;
+}
+
+/* Test DT phandle lookups using correct index or name succeed */
+static void clk_parse_clkspec_with_correct_index_and_name(struct kunit *test)
+{
+	struct clk_parse_clkspec_ctx *ctx = test->priv;
+	struct clk_hw *hw1, *hw2, *hw3, *hw4;
+
+	/* Get clocks by index */
+	hw1 = of_clk_get_hw(ctx->cons_np, 0, NULL);
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, hw1);
+
+	hw2 = of_clk_get_hw(ctx->cons_np, 1, NULL);
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, hw2);
+	KUNIT_EXPECT_PTR_NE(test, hw1, hw2);
+
+	/* Get clocks by name */
+	hw3 = of_clk_get_hw(ctx->cons_np, 0, "first_clock");
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, hw3);
+	KUNIT_EXPECT_PTR_EQ(test, hw1, hw3);
+
+	hw4 = of_clk_get_hw(ctx->cons_np, 0, "second_clock");
+	KUNIT_EXPECT_NOT_ERR_OR_NULL(test, hw4);
+	KUNIT_EXPECT_PTR_EQ(test, hw2, hw4);
+}
+
+/* Test DT phandle lookups using wrong index or name fail */
+static void clk_parse_clkspec_with_incorrect_index_and_name(struct kunit *test)
+{
+	struct clk_parse_clkspec_ctx *ctx = test->priv;
+	struct clk_hw *hw;
+
+	/* Get clock by index */
+	hw = of_clk_get_hw(ctx->cons_np, 2, NULL);
+	KUNIT_EXPECT_TRUE(test, IS_ERR(hw));
+
+	/* Get clock by name */
+	hw = of_clk_get_hw(ctx->cons_np, 0, "third_clock");
+	KUNIT_EXPECT_TRUE(test, IS_ERR(hw));
+}
+
+static struct kunit_case clk_parse_clkspec_test_cases[] = {
+	KUNIT_CASE(clk_parse_clkspec_with_correct_index_and_name),
+	KUNIT_CASE(clk_parse_clkspec_with_incorrect_index_and_name),
+	{}
+};
+
+/* Test suite to verify clk_parse_clkspec() */
+static struct kunit_suite clk_parse_clkspec_test_suite = {
+	.name = "clk_parse_clkspec",
+	.init = clk_parse_clkspec_init,
+	.test_cases = clk_parse_clkspec_test_cases,
+};
 
 kunit_test_suites(
 	&clk_assigned_rates_suite,
 	&clk_hw_get_dev_of_node_test_suite,
+	&clk_parse_clkspec_test_suite,
 	&clk_leaf_mux_set_rate_parent_test_suite,
 	&clk_test_suite,
 	&clk_multiple_parents_mux_test_suite,
@@ -3562,4 +3671,5 @@ kunit_test_suites(
 	&clk_uncached_test_suite,
 );
 MODULE_DESCRIPTION("Kunit tests for clk framework");
+MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING");
 MODULE_LICENSE("GPL v2");
diff --git a/drivers/clk/kunit_clk_parse_clkspec.dtso b/drivers/clk/kunit_clk_parse_clkspec.dtso
new file mode 100644
index 000000000000..c93feb93e101
--- /dev/null
+++ b/drivers/clk/kunit_clk_parse_clkspec.dtso
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+/dts-v1/;
+/plugin/;
+
+&{/} {
+	kunit_clock_provider1: kunit-clock-provider1 {
+		compatible = "test,clock-provider1";
+		#clock-cells = <1>;
+	};
+
+	kunit_clock_provider2: kunit-clock-provider2 {
+		compatible = "test,clock-provider2";
+		#clock-cells = <1>;
+	};
+
+	kunit-clock-consumer {
+		compatible = "test,clock-consumer";
+		clocks = <&kunit_clock_provider1 0>, <&kunit_clock_provider2 0>;
+		clock-names = "first_clock", "second_clock";
+	};
+};

-- 
2.54.0

[PATCH v4 3/7] clk: tests: Add Kunit testing for of_clk_get_parent_name()

[Miquel Raynal (Schneider Electric)]

Make sure this helper is never broken, especially since we will soon
make some changes in it.

Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
---
 drivers/clk/clk_test.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index f47f81b7d72a..4084559e157d 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -3637,9 +3637,23 @@ static void clk_parse_clkspec_with_incorrect_index_and_name(struct kunit *test)
 	KUNIT_EXPECT_TRUE(test, IS_ERR(hw));
 }
 
+/*
+ * Verify that of_clk_get_parent_name() returns the correct clock name when
+ * looking up by index through the consumer's clocks property.
+ */
+static void of_clk_get_parent_name_gets_parent_name(struct kunit *test)
+{
+	struct clk_parse_clkspec_ctx *ctx = test->priv;
+	const char *expected_name = "clk_parse_clkspec_1";
+
+	KUNIT_EXPECT_STREQ(test, expected_name,
+			   of_clk_get_parent_name(ctx->cons_np, 0));
+}
+
 static struct kunit_case clk_parse_clkspec_test_cases[] = {
 	KUNIT_CASE(clk_parse_clkspec_with_correct_index_and_name),
 	KUNIT_CASE(clk_parse_clkspec_with_incorrect_index_and_name),
+	KUNIT_CASE(of_clk_get_parent_name_gets_parent_name),
 	{}
 };
 

-- 
2.54.0

[PATCH v4 4/7] clk: Improve a couple of comments

[Miquel Raynal (Schneider Electric)]

Avoid mentioning the function names directly in the comments, it makes
them easily out of sync with the rest of the code. Use a more generic
wording.

Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
Reviewed-by: Brian Masney <bmasney@redhat.com>
---
 drivers/clk/clk.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 08874cf9b561..7d63d81ebc09 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -5202,7 +5202,7 @@ static int of_parse_clkspec(const struct device_node *np, int index,
 		/*
 		 * For named clocks, first look up the name in the
 		 * "clock-names" property.  If it cannot be found, then index
-		 * will be an error code and of_parse_phandle_with_args() will
+		 * will be an error code and the OF phandle parser will
 		 * return -EINVAL.
 		 */
 		if (name)
@@ -5275,7 +5275,7 @@ of_clk_get_hw_from_clkspec(struct of_phandle_args *clkspec)
  *
  * This function looks up a struct clk from the registered list of clock
  * providers, an input is a clock specifier data structure as returned
- * from the of_parse_phandle_with_args() function call.
+ * from the OF phandle parser.
  */
 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 {

-- 
2.54.0

[PATCH v4 5/7] clk: Use the generic OF phandle parsing in only one place

[Miquel Raynal (Schneider Electric)]

There should be one single entry in the OF world, so that the way we
parse the DT is always the same. make sure this is the case by avoid
calling of_parse_phandle_with_args() from of_clk_get_parent_name(). This
is even more relevant as we currently fail to parse clock-ranges. As a
result, it seems to be safer to directly call of_parse_clkspec() there,
but doing so implies that we do not try the "clock-ranges" path if we
already found a "clocks" property..

Suggested-by: Stephen Boyd <sboyd@kernel.org>
Fixes: 4472287a3b2f5 ("clk: Introduce of_clk_get_hw_from_clkspec()")
Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
Reviewed-by: Brian Masney <bmasney@redhat.com>
---
 drivers/clk/clk.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 7d63d81ebc09..45f5d7a4ccc1 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -5219,6 +5219,8 @@ static int of_parse_clkspec(const struct device_node *np, int index,
 		 * has a "clock-ranges" property, then we can try one of its
 		 * clocks.
 		 */
+		if (of_property_present(np, "clocks"))
+			break;
 		np = np->parent;
 		if (np && !of_property_present(np, "clock-ranges"))
 			break;
@@ -5364,8 +5366,7 @@ const char *of_clk_get_parent_name(const struct device_node *np, int index)
 	int count;
 	struct clk *clk;
 
-	rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
-					&clkspec);
+	rc = of_parse_clkspec(np, index, NULL, &clkspec);
 	if (rc)
 		return NULL;
 

-- 
2.54.0

[PATCH v4 6/7] clk: Add support for clock nexus dt bindings

[Miquel Raynal (Schneider Electric)]

A nexus node is some kind of parent device abstracting the outer
connections. They are particularly useful for describing connectors-like
interfaces but not only. Certain IP blocks will typically include inner
blocks and distribute resources to them.

In the case of clocks, there is already the concept of clock controller,
but this usually indicates some kind of control over the said clock,
ie. gate or rate control. When there is none of this, an existing
approach is to reference the upper clock, which is wrong from a hardware
point of view.

Nexus nodes are already part of the device-tree specification and clocks
are already mentioned:
https://github.com/devicetree-org/devicetree-specification/blob/v0.4/source/chapter2-devicetree-basics.rst#nexus-nodes-and-specifier-mapping

Following the introductions of nexus nodes support for interrupts, gpios
and pwms, here is the same logic applied again to the clk subsystem,
just by transitioning from of_parse_phandle_with_args() to
of_parse_phandle_with_args_map():

* Nexus OF support:
commit bd6f2fd5a1d5 ("of: Support parsing phandle argument lists through a nexus node")
* GPIO adoption:
commit c11e6f0f04db ("gpio: Support gpio nexus dt bindings")
* PWM adoption:
commit e71e46a6f19c ("pwm: Add support for pwm nexus dt bindings")

Only expected Nexus property:
- clock-map: maps inner clocks to inlet clocks
(the other properties have been judged not relevant for clocks)

Here is an example:

Example:
    soc_clk: clock-controller {
        #clock-cells = <1>;
    };

    container: container {
        #clock-cells = <1>;
        clock-map = <0 &soc_clk 2>,
                    <1 &soc_clk 6>;

        child-device {
            clocks = <&container 1>;
	    /* This is equivalent to <&soc_clk 6> */
        };
    };

The child device does not need to know about the outer implementation,
and only knows about what the nexus provides. The nexus acts as a
pass-through, with no extra control.

Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
Reviewed-by: Herve Codina <herve.codina@bootlin.com>
Reviewed-by: Brian Masney <bmasney@redhat.com>
---
 drivers/clk/clk-conf.c | 12 ++++++------
 drivers/clk/clk.c      |  4 ++--
 2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/clk/clk-conf.c b/drivers/clk/clk-conf.c
index 303a0bb26e54..5380d43b56a4 100644
--- a/drivers/clk/clk-conf.c
+++ b/drivers/clk/clk-conf.c
@@ -25,8 +25,8 @@ static int __set_clk_parents(struct device_node *node, bool clk_supplier)
 		       node);
 
 	for (index = 0; index < num_parents; index++) {
-		rc = of_parse_phandle_with_args(node, "assigned-clock-parents",
-					"#clock-cells",	index, &clkspec);
+		rc = of_parse_phandle_with_args_map(node, "assigned-clock-parents",
+						    "clock", index, &clkspec);
 		if (rc < 0) {
 			/* skip empty (null) phandles */
 			if (rc == -ENOENT)
@@ -47,8 +47,8 @@ static int __set_clk_parents(struct device_node *node, bool clk_supplier)
 			return PTR_ERR(pclk);
 		}
 
-		rc = of_parse_phandle_with_args(node, "assigned-clocks",
-					"#clock-cells", index, &clkspec);
+		rc = of_parse_phandle_with_args_map(node, "assigned-clocks",
+						    "clock", index, &clkspec);
 		if (rc < 0)
 			goto err;
 		if (clkspec.np == node && !clk_supplier) {
@@ -121,8 +121,8 @@ static int __set_clk_rates(struct device_node *node, bool clk_supplier)
 			rate = rates[index];
 
 		if (rate) {
-			rc = of_parse_phandle_with_args(node, "assigned-clocks",
-					"#clock-cells",	index, &clkspec);
+			rc = of_parse_phandle_with_args_map(node, "assigned-clocks",
+							    "clock", index, &clkspec);
 			if (rc < 0) {
 				/* skip empty (null) phandles */
 				if (rc == -ENOENT)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 45f5d7a4ccc1..6acf042673c3 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -5207,8 +5207,8 @@ static int of_parse_clkspec(const struct device_node *np, int index,
 		 */
 		if (name)
 			index = of_property_match_string(np, "clock-names", name);
-		ret = of_parse_phandle_with_args(np, "clocks", "#clock-cells",
-						 index, out_args);
+		ret = of_parse_phandle_with_args_map(np, "clocks", "clock",
+						     index, out_args);
 		if (!ret)
 			break;
 		if (name && index >= 0)

-- 
2.54.0

[PATCH v4 7/7] clk: tests: Add Kunit testing for nexus nodes

[Miquel Raynal (Schneider Electric)]

Add a nexus node with a child requesting a mapped clock in the fake DT
overlay to verify that the parsing is also correctly working.

Create an of_find_node_by_name() like kunit helper to garbage collect the
node automatically in case of failed assertion.

Suggested-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>
---
 drivers/clk/clk_kunit_helpers.c          | 31 +++++++++++++++++++++++++++++++
 drivers/clk/clk_test.c                   | 15 +++++++++++++++
 drivers/clk/kunit_clk_parse_clkspec.dtso | 10 ++++++++++
 include/kunit/clk.h                      |  2 ++
 4 files changed, 58 insertions(+)

diff --git a/drivers/clk/clk_kunit_helpers.c b/drivers/clk/clk_kunit_helpers.c
index 68a28e70bb61..daaf1cf1546c 100644
--- a/drivers/clk/clk_kunit_helpers.c
+++ b/drivers/clk/clk_kunit_helpers.c
@@ -233,5 +233,36 @@ int of_clk_add_hw_provider_kunit(struct kunit *test, struct device_node *np,
 }
 EXPORT_SYMBOL_GPL(of_clk_add_hw_provider_kunit);
 
+KUNIT_DEFINE_ACTION_WRAPPER(of_node_put_wrapper, of_node_put, struct device_node *);
+
+/**
+ * of_find_node_by_name_kunit() - Test managed of_find_node_by_name()
+ * @test: The test context
+ * @from: Parent device node to start searching from, or NULL to search from root
+ * @name: The name string to match against
+ *
+ * Just like of_find_node_by_name(), except the device_noded is managed by
+ * the test case and is automatically put after the test case concludes.
+ *
+ * Return: the device_node on success, NULL if not found, or a negative errno value on failure.
+ */
+struct device_node *of_find_node_by_name_kunit(struct kunit *test, struct device_node *from,
+					       const char *name)
+{
+	struct device_node *np;
+	int ret;
+
+	np = of_find_node_by_name(from, name);
+	if (!np)
+		return NULL;
+
+	ret = kunit_add_action_or_reset(test, of_node_put_wrapper, np);
+	if (ret)
+		return ERR_PTR(ret);
+
+	return np;
+}
+EXPORT_SYMBOL_GPL(of_find_node_by_name_kunit);
+
 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("KUnit helpers for clk providers and consumers");
diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
index 4084559e157d..0c2f1efdaa8e 100644
--- a/drivers/clk/clk_test.c
+++ b/drivers/clk/clk_test.c
@@ -3650,10 +3650,25 @@ static void of_clk_get_parent_name_gets_parent_name(struct kunit *test)
 			   of_clk_get_parent_name(ctx->cons_np, 0));
 }
 
+static void of_clk_get_hw_maps_thru_nexus(struct kunit *test)
+{
+	struct clk_parse_clkspec_ctx *ctx = test->priv;
+	struct clk_hw *expected;
+	struct device_node *np;
+
+	np = of_find_node_by_name_kunit(test, NULL, "kunit-clock-nexus-child");
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, np);
+	expected = of_clk_get_hw(ctx->cons_np, 1, NULL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, expected);
+
+	KUNIT_EXPECT_PTR_EQ(test, expected, of_clk_get_hw(np, 0, NULL));
+}
+
 static struct kunit_case clk_parse_clkspec_test_cases[] = {
 	KUNIT_CASE(clk_parse_clkspec_with_correct_index_and_name),
 	KUNIT_CASE(clk_parse_clkspec_with_incorrect_index_and_name),
 	KUNIT_CASE(of_clk_get_parent_name_gets_parent_name),
+	KUNIT_CASE(of_clk_get_hw_maps_thru_nexus),
 	{}
 };
 
diff --git a/drivers/clk/kunit_clk_parse_clkspec.dtso b/drivers/clk/kunit_clk_parse_clkspec.dtso
index c93feb93e101..a4115216d2aa 100644
--- a/drivers/clk/kunit_clk_parse_clkspec.dtso
+++ b/drivers/clk/kunit_clk_parse_clkspec.dtso
@@ -18,4 +18,14 @@ kunit-clock-consumer {
 		clocks = <&kunit_clock_provider1 0>, <&kunit_clock_provider2 0>;
 		clock-names = "first_clock", "second_clock";
 	};
+
+	kunit_clock_nexus: kunit-clock-nexus {
+		clocks = <&kunit_clock_provider2 0>;
+		clock-map = <&kunit_clock_provider2 0>;
+		#clock-cells = <0>;
+
+		kunit-clock-nexus-child {
+			clocks = <&kunit_clock_nexus>;
+		};
+	};
 };
diff --git a/include/kunit/clk.h b/include/kunit/clk.h
index f226044cc78d..ab24f7747516 100644
--- a/include/kunit/clk.h
+++ b/include/kunit/clk.h
@@ -29,5 +29,7 @@ int of_clk_hw_register_kunit(struct kunit *test, struct device_node *node,
 int of_clk_add_hw_provider_kunit(struct kunit *test, struct device_node *np,
 				 struct clk_hw *(*get)(struct of_phandle_args *clkspec, void *data),
 				 void *data);
+struct device_node *of_find_node_by_name_kunit(struct kunit *test, struct device_node *from,
+					       const char *name);
 
 #endif

-- 
2.54.0

Re: [PATCH v4 1/7] dt-bindings: clock: Introduce nexus nodes

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] The clock nexus node schema omits standard nexus properties (`clock-map-mask`, `clock-map-pass-thru`) and `#clock-cells`, breaking schema validation.
- [Medium] The binding schema entirely omits the mandatory `examples` section.
--

--- Patch [1]: [PATCH v4 1/7] dt-bindings: clock: Introduce nexus nodes ---
commit f0afb8c47352e777825bd7597a7b17705e20153d
Author: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>

dt-bindings: clock: Introduce nexus nodes

This commit introduces a new device tree binding for clock nexus nodes
to allow remapping of clock specifiers. It defines the clock-map property
but explicitly defers examples to the existing PWM nexus node binding.

> diff --git a/Documentation/devicetree/bindings/clock/clock-nexus-node.yaml b/Documentation/devicetree/bindings/clock/clock-nexus-node.yaml
> new file mode 100644
> index 0000000000000..ff3283bd5fb11
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/clock-nexus-node.yaml
[ ... ]
> +properties:
> +  clock-map:
> +    $ref: /schemas/types.yaml#/definitions/uint32-matrix
> +
> +dependentRequired:
> +  clock-map: ['#clock-cells']
> +
> +additionalProperties: true

[Severity: Medium]
The commit message states this is a literal copy-paste from the PWM nexus
node binding, but should this properties block also include the standard
nexus properties like clock-map-mask, clock-map-pass-thru, and #clock-cells?

Without these definitions and their corresponding dependentRequired constraints,
schema validation won't enforce type checks on the mask and pass-thru
properties, and won't ensure that clock-map is present when a mask is used.

> +
> +# See the original pwm-nexus-node.yaml description for examples

[Severity: Medium]
Does omitting the examples section bypass the automated dt_binding_check
tests for this specific binding?

The validation tooling uses the examples section to generate test device
trees to verify logical and syntactical constraints. Providing an example
here would ensure the schema is properly tested by the build tools.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260717-schneider-v7-2-rc1-eip201-upstream-v4-0-751547e160e5@bootlin.com?part=1

Re: [PATCH v4 3/7] clk: tests: Add Kunit testing for of_clk_get_parent_name()

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:

Pre-existing issues:
- [High] Potential use-after-free of device tree strings and clock names when returning clock parent names.
--

--- Patch [3]: [PATCH v4 3/7] clk: tests: Add Kunit testing for of_clk_get_parent_name() ---
commit 4b760cb4ff3b2b61c5f90468c3fd87c387504cd7
Author: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>

clk: tests: Add Kunit testing for of_clk_get_parent_name()

This commit adds a Kunit test to verify that of_clk_get_parent_name()
returns the correct clock name when looking up by index.

> diff --git a/drivers/clk/clk_test.c b/drivers/clk/clk_test.c
> index f47f81b7d72a4..4084559e157df 100644
> --- a/drivers/clk/clk_test.c
> +++ b/drivers/clk/clk_test.c

[ ... ]

> @@ -3637,9 +3637,23 @@ static void clk_parse_clkspec_with_incorrect_index_and_name(struct kunit *test)
>  	KUNIT_EXPECT_TRUE(test, IS_ERR(hw));
>  }
>  
> +/*
> + * Verify that of_clk_get_parent_name() returns the correct clock name when
> + * looking up by index through the consumer's clocks property.
> + */
> +static void of_clk_get_parent_name_gets_parent_name(struct kunit *test)
> +{
> +	struct clk_parse_clkspec_ctx *ctx = test->priv;
> +	const char *expected_name = "clk_parse_clkspec_1";
> +
> +	KUNIT_EXPECT_STREQ(test, expected_name,
> +			   of_clk_get_parent_name(ctx->cons_np, 0));

[Severity: High]
This isn't a bug introduced by this patch, but does of_clk_get_parent_name()
return a potentially dangling pointer here?

Looking at of_clk_get_parent_name() in drivers/clk/clk.c:

    clk_name = __clk_get_name(clk);
    clk_put(clk);
    ...
    of_node_put(clkspec.np);
    return clk_name;

The string pointer is extracted and the reference to its owning object (the
clock or the device node) is dropped before returning. If the node is from a
removed DT overlay or the clock provider is concurrently unregistered, and
this was the last reference, wouldn't the memory backing the string be freed
leaving the caller with a dangling pointer?

> +}
> +
>  static struct kunit_case clk_parse_clkspec_test_cases[] = {
>  	KUNIT_CASE(clk_parse_clkspec_with_correct_index_and_name),
>  	KUNIT_CASE(clk_parse_clkspec_with_incorrect_index_and_name),
> +	KUNIT_CASE(of_clk_get_parent_name_gets_parent_name),
>  	{}
>  };

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260717-schneider-v7-2-rc1-eip201-upstream-v4-0-751547e160e5@bootlin.com?part=3

Re: [PATCH v4 5/7] clk: Use the generic OF phandle parsing in only one place

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 3 potential issue(s) to consider:

Pre-existing issues:
- [High] Returning a dangling pointer to a device node's name after dropping the node's reference count.
- [High] Returning a dangling pointer to a clock core's name after dropping the clock reference.
- [High] Loss of the requested clock index when falling back to a parent node via the `clock-ranges` property.
--

--- Patch [5]: [PATCH v4 5/7] clk: Use the generic OF phandle parsing in only one place ---
commit ae5ff381e475c55a5d269ef4dce5a639c14cc437
Author: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>

clk: Use the generic OF phandle parsing in only one place

This commit replaces the use of of_parse_phandle_with_args() with
of_parse_clkspec() inside of_clk_get_parent_name(). It also modifies
of_parse_clkspec() to stop traversing up the device tree if a "clocks"
property is found.

> diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
> index 7d63d81ebc096..45f5d7a4ccc17 100644
> --- a/drivers/clk/clk.c
> +++ b/drivers/clk/clk.c
> @@ -5219,6 +5219,8 @@ static int of_parse_clkspec(const struct device_node *np, int index,
>  		 * has a "clock-ranges" property, then we can try one of its
>  		 * clocks.
>  		 */
> +		if (of_property_present(np, "clocks"))
> +			break;
>  		np = np->parent;
>  		if (np && !of_property_present(np, "clock-ranges"))
>  			break;

[Severity: High]
This is a pre-existing issue, but this patch significantly exacerbates it.

When falling back to the parent node via the "clock-ranges" property, does
this discard the caller's requested clock index?

drivers/clk/clk.c:of_parse_clkspec() {
		...
		np = np->parent;
		if (np && !of_property_present(np, "clock-ranges"))
			break;
		index = 0;
	}

By hardcoding index to 0 before iterating to the parent, the requested clock
index is lost. The function incorrectly looks up index 0 on the parent node
regardless of what index the caller originally requested. This breaks
index-based clock lookups for devices relying on "clock-ranges" to inherit
clocks.

Since this patch switches of_clk_get_parent_name() to use of_parse_clkspec(),
when of_clk_parent_fill() requests parents 0, 1, 2, etc., will it now silently
receive identical copies of the parent's 0th clock name for all indices and
corrupt the hardware clock tree topology?

> @@ -5364,8 +5366,7 @@ const char *of_clk_get_parent_name(const struct device_node *np, int index)
>  	int count;
>  	struct clk *clk;
>  
> -	rc = of_parse_phandle_with_args(np, "clocks", "#clock-cells", index,
> -					&clkspec);
> +	rc = of_parse_clkspec(np, index, NULL, &clkspec);
>  	if (rc)
>  		return NULL;
>  

[Severity: High]
This isn't a bug introduced by this patch, but looking further down in
of_clk_get_parent_name(), does this return a dangling pointer if the device
tree node is dynamically removed?

drivers/clk/clk.c:of_clk_get_parent_name() {
		...
		if (IS_ERR(clk)) {
			if (clkspec.args_count == 0)
				clk_name = clkspec.np->name;
			else
				clk_name = NULL;
		} else {
		...
	of_node_put(clkspec.np);
	return clk_name;
}

The string pointer clk_name is retrieved from the device node, but the
reference to the node is immediately dropped via of_node_put(clkspec.np). If
the node and its name string are freed, for example via DT overlay removal,
any subsequent access to the child's cached parent name by the clock framework
would lead to a Use-After-Free.

[Severity: High]
This is another pre-existing issue in the same function, but does this also
return a dangling pointer if the parent clock provider is dynamically
unregistered?

drivers/clk/clk.c:of_clk_get_parent_name() {
		...
		} else {
			clk_name = __clk_get_name(clk);
			clk_put(clk);
		}
	}

	of_node_put(clkspec.np);
	return clk_name;
}

The clock name is retrieved via __clk_get_name(clk), but the consumer
reference is immediately dropped via clk_put(clk). If the parent clock
provider unregisters (e.g., on driver unbind or module unload), the parent's
clk_core structure and its name string are freed. This could trigger a
Use-After-Free on any subsequent access by the child clock.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260717-schneider-v7-2-rc1-eip201-upstream-v4-0-751547e160e5@bootlin.com?part=5

Re: [PATCH v4 7/7] clk: tests: Add Kunit testing for nexus nodes

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [Medium] `of_find_node_by_name_kunit()` creates a double-free / use-after-free trap via its `from` argument.
- [Medium] `of_find_node_by_name_kunit()` returns an `ERR_PTR` on failure, breaking the expected `NULL` failure semantic of `of_find_node_by_name()`.
--

--- Patch [7]: [PATCH v4 7/7] clk: tests: Add Kunit testing for nexus nodes ---
commit abd4c1ecb509bcaa0e834d4c06b41750affacb27
Author: Miquel Raynal (Schneider Electric) <miquel.raynal@bootlin.com>

clk: tests: Add Kunit testing for nexus nodes

Add a nexus node with a child requesting a mapped clock in the fake DT
overlay to verify that the parsing is also correctly working. Create an
of_find_node_by_name() like kunit helper to garbage collect the node
automatically in case of failed assertion.

> diff --git a/drivers/clk/clk_kunit_helpers.c b/drivers/clk/clk_kunit_helpers.c
> index 68a28e70bb61c..daaf1cf1546c4 100644
> --- a/drivers/clk/clk_kunit_helpers.c
> +++ b/drivers/clk/clk_kunit_helpers.c
[ ... ]
> +struct device_node *of_find_node_by_name_kunit(struct kunit *test, struct device_node *from,
> +					       const char *name)
> +{
> +	struct device_node *np;
> +	int ret;
> +
> +	np = of_find_node_by_name(from, name);

[Severity: Medium]
Will this lead to a double-free if the from argument is another
KUnit-managed node?

of_find_node_by_name() explicitly drops the reference on its from argument.
If a test author passes a node previously returned by
of_find_node_by_name_kunit(), the underlying of_find_node_by_name() will
consume the reference immediately.

KUnit is unaware of this and will execute its deferred action at the end of the
test, calling of_node_put() a second time on the already freed node.

> +	if (!np)
> +		return NULL;
> +
> +	ret = kunit_add_action_or_reset(test, of_node_put_wrapper, np);
> +	if (ret)
> +		return ERR_PTR(ret);

[Severity: Medium]
Could this ERR_PTR() return value cause crashes for callers using standard OF
node pointer checks?

The standard of_find_node_by_name() strictly returns NULL on failure, and
callers typically check for failure using if (!np). Returning an ERR_PTR()
here means truthy checks will pass, potentially leading to an invalid pointer
dereference when the caller attempts to use the returned error pointer as a
device_node struct.

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260717-schneider-v7-2-rc1-eip201-upstream-v4-0-751547e160e5@bootlin.com?part=7