ecusb: Fix subprocess argument to make it py2/3 compatible

BUG=chromium:1031705
BRANCH=master
TEST=None

Signed-off-by: kerker <kerker@chromium.org>
Change-Id: I78713f635e00cf01e1df641436b3a6d2f5c3c00b
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2431318
Reviewed-by: Yu-Ping Wu <yupingso@chromium.org>

2 files changed, 13 insertions, 8 deletions

diff --git a/extra/tigertool/ecusb/tiny_servo_common.py b/extra/tigertool/ecusb/tiny_servo_common.py
index 0e650a2d1d..dbbe42fea8 100644
--- a/extra/tigertool/ecusb/tiny_servo_common.py
+++ b/extra/tigertool/ecusb/tiny_servo_common.py
@@ -4,6 +4,8 @@
 
 """Utilities for using lightweight console functions."""
 
+# Note: This is a py2/3 compatible file.
+
 import datetime
 import errno
 import os
@@ -12,10 +14,18 @@ import subprocess
 import sys
 import time
 
+import six
+
 from . import pty_driver
 from . import stm32uart
 
 
+def get_subprocess_args():
+  if six.PY3:
+    return {'encoding': 'utf-8'}
+  return {}
+
+
 class TinyServoError(Exception):
   """Exceptions."""
 
@@ -41,7 +51,7 @@ def check_usb(vidpid, serialname=None):
   """
   if serialname:
     output = subprocess.check_output(['lsusb', '-v', '-d', vidpid],
-                                     encoding='utf-8')
+                                     **get_subprocess_args())
     m = re.search(r'^\s*iSerial\s+\d+\s+%s$' % serialname, output, flags=re.M)
     if m:
       return True
@@ -65,7 +75,7 @@ def check_usb_sn(vidpid):
   Returns: string serial number if found, None otherwise.
   """
   output = subprocess.check_output(['lsusb', '-v', '-d', vidpid],
-                                   encoding='utf-8')
+                                   **get_subprocess_args())
   m = re.search(r'^\s*iSerial\s+(.*)$', output, flags=re.M)
   if m:
     return m.group(1)
diff --git a/extra/usb_updater/servo_updater.py b/extra/usb_updater/servo_updater.py
index 397aa28566..80a63636d8 100755
--- a/extra/usb_updater/servo_updater.py
+++ b/extra/usb_updater/servo_updater.py
@@ -16,7 +16,6 @@ import time
 import tempfile
 
 import json
-import six
 
 import fw_update
 import ecusb.tiny_servo_common as c
@@ -240,13 +239,9 @@ def find_available_version(boardname, binfile):
   Returns:
     the version string.
   """
-  args = {}
-  if six.PY3:
-    args['encoding'] = 'utf-8'
-
   rawstrings = subprocess.check_output(
       ['cbfstool', binfile, 'read', '-r', 'RO_FRID', '-f', '/dev/stdout'],
-      **args)
+      **c.get_subprocess_args())
   m = re.match(r'%s_v\S+' % boardname, rawstrings)
   if m:
     newvers = m.group(0).strip(' \t\r\n\0')