[PATCH v3] checks: Remove check for graph child addresses

[PATCH v3] checks: Remove check for graph child addresses

[Niklas Söderlund]

The dtc graph_child_address check can't distinguish between bindings
where there can only be a single endpoint, and cases where there can be
multiple endpoints.

In cases where the bindings allow for multiple endpoints but only one is
described false warnings about unnecessary #address-cells/#size-cells
can be generated, but only if the endpoint described have an address of
0 (A), for single endpoints with a non-zero address (B) no warnings are
generated.

A)
    ports {
	#address-cells = <1>;
	#size-cells = <0>;

	port@0 {
	    #address-cells = <1>;
	    #size-cells = <0>;

	    sourceA: endpoint@0 {
		reg = <0>
	    };
	};
    };

B)
    ports {
	#address-cells = <1>;
	#size-cells = <0>;

	port@0 {
	    #address-cells = <1>;
	    #size-cells = <0>;

	    sourceB: endpoint@1 {
		reg = <1>
	    };
	};
    };

Remove the check as it is somewhat redundant now that we can use schemas
to validate the full node.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
---
Changes since v3
- Update test suite in tests/run_tests.sh.
- Add Rb from Rob.

Changes since v2
- Rebase after 6.17-rc1 merge window closed.
---
 checks.c           | 27 +--------------------------
 tests/run_tests.sh |  2 --
 2 files changed, 1 insertion(+), 28 deletions(-)

diff --git a/checks.c b/checks.c
index 7e3fed5005b3..2072e1ea82dc 100644
--- a/checks.c
+++ b/checks.c
@@ -1894,31 +1894,6 @@ static void check_graph_endpoint(struct check *c, struct dt_info *dti,
 }
 WARNING(graph_endpoint, check_graph_endpoint, NULL, &graph_nodes);
 
-static void check_graph_child_address(struct check *c, struct dt_info *dti,
-				      struct node *node)
-{
-	int cnt = 0;
-	struct node *child;
-
-	if (node->bus != &graph_ports_bus && node->bus != &graph_port_bus)
-		return;
-
-	for_each_child(node, child) {
-		struct property *prop = get_property(child, "reg");
-
-		/* No error if we have any non-zero unit address */
-                if (prop && propval_cell(prop) != 0 )
-			return;
-
-		cnt++;
-	}
-
-	if (cnt == 1 && node->addr_cells != -1)
-		FAIL(c, dti, node, "graph node has single child node '%s', #address-cells/#size-cells are not necessary",
-		     node->children->name);
-}
-WARNING(graph_child_address, check_graph_child_address, NULL, &graph_nodes, &graph_port, &graph_endpoint);
-
 static struct check *check_table[] = {
 	&duplicate_node_names, &duplicate_property_names,
 	&node_name_chars, &node_name_format, &property_name_chars,
@@ -2005,7 +1980,7 @@ static struct check *check_table[] = {
 
 	&alias_paths,
 
-	&graph_nodes, &graph_child_address, &graph_port, &graph_endpoint,
+	&graph_nodes, &graph_port, &graph_endpoint,
 
 	&always_fail,
 };
diff --git a/tests/run_tests.sh b/tests/run_tests.sh
index 2e172d7a2fd0..6c604888791f 100755
--- a/tests/run_tests.sh
+++ b/tests/run_tests.sh
@@ -749,7 +749,6 @@ dtc_tests () {
     check_tests "$SRCDIR/bad-phandle-cells.dts" interrupts_extended_property
     check_tests "$SRCDIR/bad-gpio.dts" gpios_property
     check_tests "$SRCDIR/good-gpio.dts" -n gpios_property
-    check_tests "$SRCDIR/bad-graph.dts" graph_child_address
     check_tests "$SRCDIR/bad-graph.dts" graph_port
     check_tests "$SRCDIR/bad-graph.dts" graph_endpoint
     check_tests "$SRCDIR/bad-graph-root1.dts" graph_nodes
@@ -758,7 +757,6 @@ dtc_tests () {
     check_tests "$SRCDIR/bad-graph-root4.dts" graph_nodes
     check_tests "$SRCDIR/bad-graph-reg-cells.dts" graph_endpoint
     check_tests "$SRCDIR/bad-graph-reg-cells.dts" graph_port
-    check_tests "$SRCDIR/bad-graph-child-address.dts" graph_child_address
     run_sh_test "$SRCDIR/dtc-checkfails.sh" deprecated_gpio_property -- -Wdeprecated_gpio_property -I dts -O dtb "$SRCDIR/bad-gpio.dts"
     run_sh_test "$SRCDIR/dtc-checkfails.sh" -n deprecated_gpio_property -- -Wdeprecated_gpio_property -I dts -O dtb "$SRCDIR/good-gpio.dts"
     check_tests "$SRCDIR/bad-interrupt-cells.dts" interrupts_property
-- 
2.50.1

Re: [PATCH v3] checks: Remove check for graph child addresses

[David Gibson]

[-- Attachment #1: Type: text/plain, Size: 1463 bytes --]

On Sun, Aug 17, 2025 at 03:37:33PM +0200, Niklas Söderlund wrote:
> The dtc graph_child_address check can't distinguish between bindings
> where there can only be a single endpoint, and cases where there can be
> multiple endpoints.
> 
> In cases where the bindings allow for multiple endpoints but only one is
> described false warnings about unnecessary #address-cells/#size-cells
> can be generated, but only if the endpoint described have an address of
> 0 (A), for single endpoints with a non-zero address (B) no warnings are
> generated.
> 
> A)
>     ports {
> 	#address-cells = <1>;
> 	#size-cells = <0>;
> 
> 	port@0 {
> 	    #address-cells = <1>;
> 	    #size-cells = <0>;
> 
> 	    sourceA: endpoint@0 {
> 		reg = <0>
> 	    };
> 	};
>     };
> 
> B)
>     ports {
> 	#address-cells = <1>;
> 	#size-cells = <0>;
> 
> 	port@0 {
> 	    #address-cells = <1>;
> 	    #size-cells = <0>;
> 
> 	    sourceB: endpoint@1 {
> 		reg = <1>
> 	    };
> 	};
>     };
> 
> Remove the check as it is somewhat redundant now that we can use schemas
> to validate the full node.
> 
> Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
> Reviewed-by: Rob Herring (Arm) <robh@kernel.org>

Applied, thanks.

-- 
David Gibson (he or they)	| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you, not the other way
				| around.
http://www.ozlabs.org/~dgibson

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