migen/genlib/misc: replace Timeout with WaitTimer from artiq

migen/genlib/misc.py

@@ -118,12 +118,16 @@ class Counter(Module):
         self.sync += self.value.eq(self.value+increment)
 
 
-@ResetInserter()
-@CEInserter()
-class Timeout(Module):
-    def __init__(self, length):
-        self.reached = Signal()
-        ###
-        value = Signal(max=length)
-        self.sync += If(~self.reached, value.eq(value+1))
-        self.comb += self.reached.eq(value == (length-1))
+class WaitTimer(Module):
+    def __init__(self, t):
+        self.wait = Signal()
+        self.done = Signal()
+
+        # # #
+
+        count = Signal(bits_for(t), reset=t)
+        self.comb += self.done.eq(count == 0)
+        self.sync += \
+            If(self.wait,
+                If(~self.done, count.eq(count - 1))
+            ).Else(count.eq(count.reset))