CLI command to format C code

docs/cli.md

@@ -36,3 +36,13 @@ qmk compile <configuratorExport.json>
 ```
 qmk compile -kb <keyboard_name> -km <keymap_name>
 ```
+
+## `qmk cformat`
+
+This command formats C code using clang-format. Run it with no arguments to format all core code, or pass filenames on the command line to run it on specific files.
+
+**Usage**:
+
+```
+qmk cformat [file1] [file2] [...] [fileN]
+```

lib/python/qmk/cli/cformat.py

@@ -0,0 +1,27 @@
+"""Format C code according to QMK's style.
+"""
+import os
+import subprocess
+
+from milc import cli
+
+
+@cli.entrypoint("Format C code according to QMK's style.")
+def main(cli):
+    """Format C code according to QMK's style.
+    """
+    clang_format = ['clang-format', '-i']
+    code_files = []
+    for dir in ['drivers', 'quantum', 'tests', 'tmk_core']:
+        for dirpath, dirnames, filenames in os.walk(dir):
+            if 'tmk_core/protocol/usb_hid' in dirpath:
+                continue
+            for name in filenames:
+                if name.endswith('.c') or name.endswith('.h') or name.endswith('.cpp'):
+                    code_files.append(os.path.join(dirpath, name))
+
+    try:
+        subprocess.run(clang_format + code_files, check=True)
+        cli.log.info('Successfully formatted the C code.')
+    except subprocess.CalledProcessError:
+        cli.log.error('Error formatting C code!')