Leverage dtsfmt as the standard formatter for DTS and DTSI files

- Add `.dtsfmtrc.toml` with formatting rules and apply dtsfmt in
  .ci/check-format.sh. The formatting rules are as follows:
  * Use spaces for indentation.
  * Indent with 4 spaces.
  * Use Multi-line comment.
  * Use Unix-style line endings (LF).
  * Remove trailing whitespace at the end of lines.
  * Ensure the file ends with a newline.

- Update CONTRIBUTING.md with formatting rules and usage instructions.
  Contributors must ensure consistent DST and DTSI style before code
  submission.

- The .ci/check-format.sh’s exit code includes dtsfmt's exit code, which
  should be 0 if all DTS and DTSI files are properly formatted.

- The make format integrates the dtsfmt.

- All existing DTS and DTSI are reformatted with the aforementioned
  formatting rules.

- Remove non-used REPO_ROOT variable in .ci/check-format.sh.

Author: ChinYikMing

.ci/check-format.sh

@@ -4,8 +4,6 @@
 
 set -u -o pipefail
 
-REPO_ROOT="$(git rev-parse --show-toplevel)"
-
 # Use git ls-files to exclude submodules and untracked files
 C_SOURCES=()
 while IFS= read -r file; do
@@ -58,4 +56,20 @@ else
     PY_FORMAT_EXIT=0
 fi
 
-exit $((C_FORMAT_EXIT + SH_FORMAT_EXIT + PY_FORMAT_EXIT))
+DTS_SOURCES=()
+while IFS= read -r file; do
+    [ -n "$file" ] && DTS_SOURCES+=("$file")
+done < <(git ls-files -- '*.dts' '*.dtsi')
+
+if [ ${#DTS_SOURCES[@]} -gt 0 ]; then
+    echo "Checking DTS/DTSI files..."
+    DTS_FORMAT_EXIT=0
+    for dts_src in "${DTS_SOURCES[@]}"; do
+        dtsfmt --check "${dts_src}"
+        DTS_FORMAT_EXIT=$((DTS_FORMAT_EXIT + $?))
+    done
+else
+    DTS_FORMAT_EXIT=0
+fi
+
+exit $((C_FORMAT_EXIT + SH_FORMAT_EXIT + PY_FORMAT_EXIT + DTS_FORMAT_EXIT))

.dtsfmtrc.toml

@@ -0,0 +1,2 @@
+indent_str = "    "
+warn_on_unhandled_tokens = true

.github/workflows/main.yml

@@ -594,6 +594,7 @@ jobs:
       run: |
             sudo apt-get install -q=2 clang-format-18 shfmt python3-pip
             pip3 install black==25.1.0
+            curl -LSfs https://go.mskelton.dev/dtsfmt/install | sh -s -- -y
             .ci/check-newline.sh
             .ci/check-format.sh
       shell: bash

CONTRIBUTING.md

@@ -50,12 +50,24 @@ Software requirement:
 * [clang-format](https://clang.llvm.org/docs/ClangFormat.html) version 18.
 * [shfmt](https://github.com/mvdan/sh).
 * [black](https://github.com/psf/black) version 25.1.0.
+* [dtsfmt](https://github.com/mskelton/dtsfmt).
 
 To maintain a uniform style across languages, run:
 * `clang-format -i *.{c,h}` to apply the project’s C/C++ formatting rules from the up-to-date .clang-format file.
 * `shfmt -w $(find . -type f -name "*.sh")` to clean and standardize all shell scripts.
 * `black .` to enforce a consistent, idiomatic layout for Python code.
-* `make format` to automatically run all three formatters.
+* `dtsfmt ./src/devices/` to enforce a consistent layout for device tree source (and include).
+* `make format` to automatically run all four formatters.
+
+## Coding Style for Device Tree Source and Device Tree Source Include
+
+Device Tree Source (and Include) must be clean, consistent, and portable. The following `dtsfmt` rules(check `.dtsfmtrc.toml` file) are enforced project-wide:
+* Use spaces for indentation.
+* Indent with 4 spaces.
+* Use multi-line comments.
+* Use Unix-style line endings (LF).
+* Remove trailing whitespace at the end of lines.
+* Ensure the file ends with a newline.
 
 ## Coding Style for Shell Script
 

Makefile

@@ -492,6 +492,8 @@ CLANG_FORMAT := $(shell which clang-format-18 2>/dev/null)
 
 SHFMT := $(shell which shfmt 2>/dev/null)
 
+DTSFMT := $(shell which dtsfmt 2>/dev/null)
+
 BLACK := $(shell which black 2>/dev/null)
 BLACK_VERSION := $(if $(strip $(BLACK)),$(shell $(BLACK) --version | head -n 1 | awk '{print $$2}'),)
 BLACK_MAJOR := $(shell echo $(BLACK_VERSION) | cut -f1 -d.)
@@ -520,6 +522,15 @@ else
 	$(Q)$(SHFMT) -w $(shell find . \( $(SUBMODULES_PRUNE_PATHS) -o -path \"./$(OUT)\" \) \
 		                        -prune -o -name "*.sh" -print)
 endif
+ifeq ($(DTSFMT),)
+	$(error dtsfmt not found. Install dtsfmt and try again)
+else
+	$(Q)for dts_src in $$(find . \( $(SUBMODULES_PRUNE_PATHS) -o -path "./$(OUT)" \) \
+					-prune -o \( -name "*.dts" -o -name "*.dtsi" \) -print); \
+	do \
+		$(DTSFMT) $$dts_src; \
+	done
+endif
 ifeq ($(BLACK),)
 	$(error black not found. Install black version 25.1.0 or above and try again)
 else

src/devices/minimal.dts

@@ -8,24 +8,24 @@
     aliases {
         serial0 = "/soc@F0000000/serial@4000000";
     };
-
     chosen {
         bootargs = "earlycon console=ttyS0";
         stdout-path = "serial0";
         linux,initrd-start = <INITRD_START>;
         linux,initrd-end = <INITRD_END>;
     };
-
     cpus {
         #address-cells = <1>;
         #size-cells = <0>;
         timebase-frequency = <65000000>;
+
         cpu0: cpu@0 {
             device_type = "cpu";
             compatible = "riscv";
             reg = <0>;
             riscv,isa = "rv32ima";
             mmu-type = "riscv,sv32";
+
             cpu0_intc: interrupt-controller {
                 #interrupt-cells = <1>;
                 #address-cells = <0>;
@@ -34,13 +34,11 @@
             };
         };
     };
-
     sram: memory@0 {
         device_type = "memory";
         reg = <MEM_START MEM_END>;
         reg-names = "sram0";
     };
-
     soc: soc@F0000000 {
         #address-cells = <1>;
         #size-cells = <1>;
@@ -57,13 +55,14 @@
             interrupts-extended = <&cpu0_intc 9>;
             riscv,ndev = <31>;
         };
-
         serial@4000000 {
             compatible = "ns16550";
             reg = <0x4000000 0x100000>;
             interrupts = <1>;
             no-loopback-test;
-            clock-frequency = <5000000>; /* the baudrate divisor is ignored */
+            clock-frequency = <5000000>;
+
+            /* the baudrate divisor is ignored */
         };
 
         /*