Exempt 'ports' from the rule which asserts that nodes with single child node having reg = 0, should not have the '#size-cells' and '#address-cells' properties. Ports of certain hardware do need to be described as only having a single child node 'port@0', especially when hardware has multiple ports, and the other ports 'port@x' are planned to be added subsequently. In such cases, just using 'port', would be an inaccurate hardware description. For example, Texas Instruments' DSS (display-subsystem), which has 2 or 4 video ports depending on the SoC. Describing the first video port with just 'port' under ports would be inaccurate and even slightly misleading. Simply using port@0 (when other ports are not added) produces the following warning, while making dtbs with W=1 flag set[0]. code-block :: Warning (graph_child_address): /bus@100000/dss@4a00000/ports: graph node has single child node 'port@0', #address-cells/#size-cells are not necessary Signed-off-by: Aradhya Bhatia <a-bhatia1@xxxxxx> [0]: https://lore.kernel.org/all/570903b6-8239-d44a-5fac-71700804cb5d@xxxxxx/ --- scripts/dtc/checks.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/scripts/dtc/checks.c b/scripts/dtc/checks.c index 9f31d2607182..705aa0fbcfa2 100644 --- a/scripts/dtc/checks.c +++ b/scripts/dtc/checks.c @@ -1797,9 +1797,18 @@ static void check_graph_child_address(struct check *c, struct dt_info *dti, cnt++; } - if (cnt == 1 && node->addr_cells != -1) + if (cnt == 1 && node->addr_cells != -1) { + /* + * The graph node "ports" are exempt from this rule, because + * certain hardware do need to be described as only having a + * signle port with reg = 0. + */ + if (!strcmp(node->name, "ports")) + return; + 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); base-commit: e3b18f7200f45d66f7141136c25554ac1e82009b -- 2.40.1
