dtoc: Process driver aliases along with drivers

Instead of using a separate step for this processing, handle it while
scanning its associated driver. This allows us to drop the code coverage
exception in this case.

Note that only files containing drivers are scanned by dtoc, so aliases
declared in a file that doesn't hold a driver will not be noticed. It
would be confusing to put them anywhere other than in the driver that they
relate to, but update the documentation to say this explicitly, just in
case.

Signed-off-by: Simon Glass <sjg@chromium.org>

tools/dtoc/src_scan.py

@@ -387,6 +387,7 @@ class Scanner:
                 in the file
             _of_match - updated with each compatible string found in the file
             _compat_to_driver - Maps compatible string to Driver
+            _driver_aliases - Maps alias names to driver name
 
         Args:
             fname (str): Filename being parsed (used for warnings)
@@ -438,6 +439,7 @@ class Scanner:
 
         re_phase = re.compile('^\s*DM_PHASE\((.*)\).*$')
         re_hdr = re.compile('^\s*DM_HEADER\((.*)\).*$')
+        re_alias = re.compile(r'DM_DRIVER_ALIAS\(\s*(\w+)\s*,\s*(\w+)\s*\)')
 
         # Matches the struct name for priv, plat
         re_priv = self._get_re_for_member('priv_auto')
@@ -522,8 +524,11 @@ class Scanner:
                 driver = Driver(driver_name, fname)
             else:
                 ids_m = re_ids.search(line)
+                m_alias = re_alias.match(line)
                 if ids_m:
                     ids_name = ids_m.group(1)
+                elif m_alias:
+                    self._driver_aliases[m_alias[2]] = m_alias[1]
 
         # Make the updates based on what we found
         self._drivers.update(drivers)
@@ -557,17 +562,6 @@ class Scanner:
             if 'UCLASS_DRIVER' in buff:
                 self._parse_uclass_driver(fname, buff)
 
-            # The following re will search for driver aliases declared as
-            # DM_DRIVER_ALIAS(alias, driver_name)
-            driver_aliases = re.findall(
-                r'DM_DRIVER_ALIAS\(\s*(\w+)\s*,\s*(\w+)\s*\)',
-                buff)
-
-            for alias in driver_aliases: # pragma: no cover
-                if len(alias) != 2:
-                    continue
-                self._driver_aliases[alias[1]] = alias[0]
-
     def scan_header(self, fname):
         """Scan a header file to build a list of struct definitions