[PATCH v3 5/6] dtc: dt-check-style: Do not sort top-level nodes in DTS by unit address

[Krzysztof Kozlowski]

Top-level DTS (but not example in the bindings) has only two nodes with
unit-addresses: memory@ and soc@.  There are two special cases here, in
terms of coding style:

1. The unit-address of memory is often not known thus set to @0, because
   it is filled up by bootloader.

2. There is mixture of non-unit-address and unit-address nodes.

Therefore usually the DTS chooses sorting by the node name, not the unit
address, for the top-level part.  Disable sorting by the unit address if
depth of node is less than '2'.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>

---

Changes in v3:
New patch
---
 scripts/dtc/dt-check-style                         |  8 ++++-
 .../dt-style-selftest/bad/dts-digit-node-order.dts | 40 ++++++++++++++++++++++
 .../expected/dts-digit-node-order.dts.txt          |  2 ++
 3 files changed, 49 insertions(+), 1 deletion(-)

diff --git a/scripts/dtc/dt-check-style b/scripts/dtc/dt-check-style
index d9080297bd4d..3c1aa9e28347 100755
--- a/scripts/dtc/dt-check-style
+++ b/scripts/dtc/dt-check-style
@@ -515,12 +515,18 @@ def _natural_sort_key(s):
 
 def check_child_address_order(ctx):
     """Addressed siblings (foo@N) must appear in ascending address
-    order within their parent node body."""
+    order within their parent node body.
+    Exception: Top-level in DTS follows name order, regardless of unit address
+    in memory@N and soc@N nodes
+    """
     for children in _walk_bodies(ctx.lines):
         addressed = []
         for c in children:
             if c.node_addr is None:
                 continue
+            if (ctx.file_type == 'dts') and (c.depth < 2):
+                # Top-level does not use unit address sorting usually
+                continue
             try:
                 parts = tuple(int(p, 16) for p in c.node_addr.split(','))
             except ValueError:
diff --git a/scripts/dtc/dt-style-selftest/bad/dts-digit-node-order.dts b/scripts/dtc/dt-style-selftest/bad/dts-digit-node-order.dts
new file mode 100644
index 000000000000..29b931ccfdbd
--- /dev/null
+++ b/scripts/dtc/dt-style-selftest/bad/dts-digit-node-order.dts
@@ -0,0 +1,40 @@
+// SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+/ {
+	#address-cells = <1>;
+	#size-cells = <1>;
+
+	memory@a0000000 {
+		device_type = "memory";
+		reg = <0x0 0xa0000000 0x0 0x0>;
+	};
+
+	pmu {
+		compatible = "example,pmu";
+	};
+
+	soc@0 {
+		compatible = "simple-bus";
+		ranges = <0 0 0 0xc0000000>;
+
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		serial@20000 {
+			compatible = "example,serial";
+			reg = <0x20000 0x1000>;
+		};
+
+		interrupt-controller@10000 {
+			compatible = "example,intc";
+			reg = <0x10000 0x1000>;
+			interrupts = <1 2 3>,
+				     <4 5 6>,
+				     <7 8 9>;
+		};
+
+		serial@30000 {
+			compatible = "example,serial";
+			reg = <0x30000 0x1000>;
+		};
+	};
+};
diff --git a/scripts/dtc/dt-style-selftest/expected/dts-digit-node-order.dts.txt b/scripts/dtc/dt-style-selftest/expected/dts-digit-node-order.dts.txt
new file mode 100644
index 000000000000..4d681ea4f639
--- /dev/null
+++ b/scripts/dtc/dt-style-selftest/expected/dts-digit-node-order.dts.txt
@@ -0,0 +1,2 @@
+# mode=strict
+bad/dts-digit-node-order.dts:27: [child-address-order] child node @10000 out of address order

-- 
2.53.0