patman: check git format.subjectprefix setting when generate patches prefix

For the local project, we may specified format.subjectprefix setting.
Then the patch will be formated as [Project_prefix][PATCH].
But patman will not check this setting. It will remove the
format.subjectprefix.

So This patch will let patman check this setting and add it as a
project prefix.

Signed-off-by: Josh Wu <josh.wu@atmel.com>
Acked-by: Simon Glass <sjg@chromium.org>
Tested-by: Simon Glass <sjg@chromium.org>

tools/patman/README

@@ -154,7 +154,11 @@ Series-version: n
 
 Series-prefix: prefix
 	Sets the subject prefix. Normally empty but it can be RFC for
-	RFC patches, or RESEND if you are being ignored.
+	RFC patches, or RESEND if you are being ignored. The patch subject
+	is like [RFC PATCH] or [RESEND PATCH].
+	In the meantime, git format.subjectprefix option will be added as
+	well. If your format.subjectprefix is set to InternalProject, then
+	the patch shows like: [InternalProject][RFC/RESEND PATCH]
 
 Series-name: name
 	Sets the name of the series. You don't need to have a name, and

tools/patman/gitutil.py

@@ -545,6 +545,17 @@ def GetDefaultUserEmail():
     uemail = command.OutputOneLine('git', 'config', '--global', 'user.email')
     return uemail
 
+def GetDefaultSubjectPrefix():
+    """Gets the format.subjectprefix from local .git/config file.
+
+    Returns:
+        Subject prefix found in local .git/config file, or None if none
+    """
+    sub_prefix = command.OutputOneLine('git', 'config', 'format.subjectprefix',
+                 raise_on_error=False)
+
+    return sub_prefix
+
 def Setup():
     """Set up git utils, by reading the alias files."""
     # Check for a git alias file also

tools/patman/series.py

@@ -254,6 +254,12 @@ class Series(dict):
         Return:
             Patch string, like 'RFC PATCH v5' or just 'PATCH'
         """
+        git_prefix = gitutil.GetDefaultSubjectPrefix()
+        if git_prefix:
+	    git_prefix = '%s][' % git_prefix
+        else:
+            git_prefix = ''
+
         version = ''
         if self.get('version'):
             version = ' v%s' % self['version']
@@ -262,4 +268,4 @@ class Series(dict):
         prefix = ''
         if self.get('prefix'):
             prefix = '%s ' % self['prefix']
-        return '%sPATCH%s' % (prefix, version)
+        return '%s%sPATCH%s' % (git_prefix, prefix, version)