2 files changed, 31 insertions(+), 17 deletions(-)

M patch/common/pll.yaml
M patch/svdpatch.py

@@ 2,29 2,24 @@
 #
 # - Make the Lock Detector field read-only
 # - Add descriptions for "Input Multiplexer" and "USB Postscaler"
-# - Remove and re-add the "Lock Frequency" and Postscaler fields
-#   to fix <https://github.com/Rahix/atdf2svd/issues/1>.
+# - Add enumerated values to "Lock Frequency" and Postscaler fields
 PLL:
   PLLCSR:
     _modify:
       PLOCK:
         access: read-only
   PLLFRQ:
-    _delete:
-      - PDIV
-      - PLLTM
     _modify:
       PINMUX:
         description: "PLL Input Multiplexer"
       PLLUSB:
         description: "PLL Postscaler for USB Peripheral"
-    _add:
       PDIV:
         description: "PLL Lock Frequency"
-        bitRange: "[3:0]"
+        _write_constraint: none
       PLLTM:
         description: "PLL Postscaler for High Speed Timer"
-        bitRange: "[5:4]"
+        _write_constraint: enum
     PDIV:
       MHZ40: [0b0011, "40 MHz"]
       MHZ48: [0b0100, "48 MHz"]

@@ 10,6 10,7 @@ To be integrated into the build system, support for an input / output svd argume
 Additional changes:
     - Support for _replace_enum to overwrite existing <enumeratedValues>
     - Fix field modifications not being able to add new elements
+    - Add _write_constraint modifier for changing the <writeConstraint>
 """
 
 import copy


@@ 221,16 222,34 @@ def process_register_modify(rtag, fspec, fmod):
     """Modify fspec inside rtag according to fmod."""
     for ftag in iter_fields(rtag, fspec):
         for (key, value) in fmod.items():
-            try:
-                tag = ftag.find(key)
-                if tag is None:
-                    tag = ET.SubElement(ftag, key)
+            if key == "_write_constraint":
+                key = "writeConstraint"
+
+            tag = ftag.find(key)
+            if tag is None:
+                tag = ET.SubElement(ftag, key)
+
+            if key == "writeConstraint":
+                # Remove existing constraint contents
+                for child in list(tag):
+                    tag.remove(child)
+                if value == "none":
+                    # Completely remove the existing writeConstraint
+                    ftag.remove(tag)
+                elif value == "enum":
+                    # Only allow enumerated values
+                    enum_tag = ET.SubElement(tag, "useEnumeratedValues")
+                    enum_tag.text = "true"
+                elif isinstance(value, list):
+                    # Allow a certain range
+                    range_tag = make_write_constraint(value).find("range")
+                    tag.append(range_tag)
+                else:
+                    raise SvdPatchError('Unknown writeConstraint type {}'
+                                        .format(repr(value)))
+            else:
+                # For all other tags, just set the value
                 tag.text = str(value)
-            except AttributeError:
-                raise SvdPatchError('invalid attribute {!r} for '
-                                    'register {}, field {}'
-                                    .format(key, rtag.find('name').text,
-                                            ftag.find('name').text))
 
 
 def process_device_add(device, pname, padd):