timer: revert prescaler (we will in fact use a software prescaler for uIP)

misoclib/cpu/peripherals/timer/__init__.py

@@ -1,14 +1,12 @@
 from migen.fhdl.std import *
 from migen.bank.description import *
 from migen.bank.eventmanager import *
-from migen.genlib.misc import Counter
 
 class Timer(Module, AutoCSR):
-	def __init__(self, width=32, prescaler_width=32):
+	def __init__(self, width=32):
 		self._load = CSRStorage(width)
 		self._reload = CSRStorage(width)
 		self._en = CSRStorage()
-		self._prescaler = CSRStorage(prescaler_width, reset=1)
 		self._update_value = CSR()
 		self._value = CSRStatus(width)
 
@@ -17,28 +15,14 @@ class Timer(Module, AutoCSR):
 		self.ev.finalize()
 
 		###
-		enable = self._en.storage
-		tick = Signal()
-
-		counter = Counter(prescaler_width)
-		self.submodules += counter
-		self.comb += [
-			If(enable,
-				tick.eq(counter.value >= (self._prescaler.storage-1)),
-				counter.ce.eq(1),
-				counter.reset.eq(tick),
-			).Else(
-				counter.reset.eq(1)
-			)
-		]
 
 		value = Signal(width)
 		self.sync += [
-			If(enable,
+			If(self._en.storage,
 				If(value == 0,
 					# set reload to 0 to disable reloading
 					value.eq(self._reload.storage)
-				).Elif(tick,
+				).Else(
 					value.eq(value - 1)
 				)
 			).Else(