adds a way to write query-cc-mode reults as a json

This change provides more programmable way to query CC mode
without dependency on drivers.

Author: stackbaek

cli/per_gpu.py

@@ -221,7 +221,20 @@ def main_per_gpu(gpu, opts):
             return False
 
         cc_mode = gpu.query_cc_mode()
-        info(f"{gpu} CC mode is {cc_mode}")
+        output_data = {
+            "gpu_bdf": str(gpu.bdf),
+            "cc_mode": cc_mode
+        }
+        print(json.dumps(output_data))
+
+        if opts.output_json_file:
+            try:
+                with open(opts.output_json_file, 'w') as f:
+                    json.dump(output_data, f, indent=4)
+                info(f"CC mode query result written to {opts.output_json_file}")
+            except IOError as e:
+                error(f"Failed to write CC mode query result to {opts.output_json_file}: {e}")
+                return False
 
         if opts.output_json_file:
             output_data = {