[PATCH 8/9] dtc: dt-check-style: Introduce 'stricter' mode

[Krzysztof Kozlowski]

Two rules, which are enabled in 'strict' mode make little sense for DTS:

1. line-length, limiting length of line to 80 characters: DTS often has
   a bit longer lines, especially for interconnects or heavily nested
   opp-level.  Checkpatch already does not warn for exceeding 80
   characters.

2. unused-labels, discouraging unused labels in DTS or YAML (not DTSI or
   DTSO): while not harming this leads to many false positives, e.g.
   unused PMIC regulators in DTS.

Introduce another 'mode' of running beside existing relaxed and strict:
a 'stricter' one where these two rules are moved for DTS.  Intention is
to have in-tree DTS passing 'strict' mode.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@xxxxxxxxxxxxxxxx>
---
 scripts/dtc/dt-check-style                         | 26 +++++++++++++++-------
 .../dtc/dt-style-selftest/bad/dts-line-length.dts  | 21 +++++++++++++++++
 .../dtc/dt-style-selftest/bad/dts-unused-label.dts | 21 +++++++++++++++++
 .../expected/dts-line-length.dts.txt               |  2 ++
 .../expected/dts-unused-label.dts.txt              |  2 ++
 5 files changed, 64 insertions(+), 8 deletions(-)

diff --git a/scripts/dtc/dt-check-style b/scripts/dtc/dt-check-style
index 8c049c04b865..7e1d80ceab78 100755
--- a/scripts/dtc/dt-check-style
+++ b/scripts/dtc/dt-check-style
@@ -5,12 +5,14 @@
 # .dts/.dtsi/.dtso source files. Enforces rules from
 # Documentation/devicetree/bindings/dts-coding-style.rst.
 #
-# Two modes:
+# Three modes:
 #   --mode=relaxed (default)
 #     Only rules that produce zero warnings on the current tree.
 #     Suitable for dt_binding_check.
 #   --mode=strict
-#     All rules. Required for new submissions.
+#     Most of the rules. Required for new submissions.
+#   --mode=stricter
+#     All rules, including ones having false positives.
 #
 # Two input types (auto-detected by file extension):
 #   *.yaml             -- DT binding; check each example block
@@ -319,7 +321,7 @@ class Ctx:
     def __init__(self, lines, text, mode, file_type):
         self.lines = lines
         self.text = text
-        self.mode = mode               # 'relaxed' or 'strict'
+        self.mode = mode               # 'relaxed', 'strict' or 'stricter'
         if file_type in DTS_FAMILY:
             self.file_type = 'dts'
         else:
@@ -332,7 +334,8 @@ class Rule:
     def __init__(self, name, mode, description, check,
                  applies_to=('yaml', 'dts', 'dtsi', 'dtso')):
         self.name = name
-        self.mode = mode               # 'relaxed' or 'strict'
+        # 'relaxed', 'strict', 'stricter' ordictionary mapping file_type to mode
+        self.mode = mode
         self.description = description
         self.check = check
         self.applies_to = applies_to   # input types this rule covers
@@ -1042,20 +1045,27 @@ RULES = [
          check_node_close_alone),
     Rule('line-length', 'strict',
          'lines must not exceed 80 columns',
-         check_line_length),
+         check_line_length, applies_to=('yaml')),
+    Rule('line-length-dts', 'stricter',
+         'lines must not exceed 80 columns',
+         check_line_length, applies_to=('dts', 'dtsi', 'dtso')),
     Rule('continuation-alignment', 'strict',
          'multi-line property continuations align under "<" or "\\""',
          check_continuation_alignment),
     Rule('unused-labels', 'strict',
          'every label must be &-referenced in the same example/file '
          '(skipped for .dtsi/.dtso since labels there are exported)',
-         check_unused_labels, applies_to=('yaml', 'dts')),
+         check_unused_labels, applies_to=('yaml')),
+    Rule('unused-labels-dts', 'stricter',
+         'every label must be &-referenced in the same example/file '
+         '(skipped for .dtsi/.dtso since labels there are exported)',
+         check_unused_labels, applies_to=('dts')),
 ]
 
 
 def select_rules(mode, file_type):
     """Return rules that apply to the given mode and input type."""
-    rank = {'relaxed': 0, 'strict': 1}
+    rank = {'relaxed': 0, 'strict': 1, 'stricter': 2}
     out = []
     for r in RULES:
         if rank[r.mode] > rank[mode]:
@@ -1183,7 +1193,7 @@ def main():
         description='Check DTS coding style on YAML examples and '
         '.dts/.dtsi/.dtso files.',
         fromfile_prefix_chars='@')
-    ap.add_argument('--mode', choices=('relaxed', 'strict'),
+    ap.add_argument('--mode', choices=('relaxed', 'strict', 'stricter'),
                     default='relaxed',
                     help='which rule set to apply (default: relaxed)')
     ap.add_argument('-j', '--jobs', type=int, default=0,
diff --git a/scripts/dtc/dt-style-selftest/bad/dts-line-length.dts b/scripts/dtc/dt-style-selftest/bad/dts-line-length.dts
new file mode 100644
index 000000000000..d1dacc5c76fb
--- /dev/null
+++ b/scripts/dtc/dt-style-selftest/bad/dts-line-length.dts
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+/*
+ * Test fixture: Unused label in DTS
+ */
+
+/dts-v1/;
+
+/ {
+	soc@0 {
+		compatible = "simple-bus";
+		ranges = <0 0 0 0xc0000000>;
+
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		foo@1000 {
+			compatible = "example,test-line-length-this-is-a-very-long-name-indeed-yeah";
+			reg = <0x1000 0x100>;
+		};
+	};
+};
diff --git a/scripts/dtc/dt-style-selftest/bad/dts-unused-label.dts b/scripts/dtc/dt-style-selftest/bad/dts-unused-label.dts
new file mode 100644
index 000000000000..90802ae107e1
--- /dev/null
+++ b/scripts/dtc/dt-style-selftest/bad/dts-unused-label.dts
@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
+/*
+ * Test fixture: Unused label in DTS
+ */
+
+/dts-v1/;
+
+/ {
+	soc@0 {
+		compatible = "simple-bus";
+		ranges = <0 0 0 0xc0000000>;
+
+		#address-cells = <1>;
+		#size-cells = <1>;
+
+		dev: device@1000 {
+			compatible = "example,test-unused-label";
+			reg = <0x1000 0x100>;
+		};
+	};
+};
diff --git a/scripts/dtc/dt-style-selftest/expected/dts-line-length.dts.txt b/scripts/dtc/dt-style-selftest/expected/dts-line-length.dts.txt
new file mode 100644
index 000000000000..8ed08c309632
--- /dev/null
+++ b/scripts/dtc/dt-style-selftest/expected/dts-line-length.dts.txt
@@ -0,0 +1,2 @@
+# mode=stricter
+bad/dts-line-length.dts:17: [line-length-dts] line exceeds 80 columns (101)
diff --git a/scripts/dtc/dt-style-selftest/expected/dts-unused-label.dts.txt b/scripts/dtc/dt-style-selftest/expected/dts-unused-label.dts.txt
new file mode 100644
index 000000000000..4cdcaba3ba2f
--- /dev/null
+++ b/scripts/dtc/dt-style-selftest/expected/dts-unused-label.dts.txt
@@ -0,0 +1,2 @@
+# mode=stricter
+bad/dts-unused-label.dts:16: [unused-labels-dts] label 'dev' defined but never &-referenced

-- 
2.53.0