diff --git a/constants/ecp5_platforms.py b/constants/ecp5_platforms.py
index c973967a7..8bca17145 100644
--- a/constants/ecp5_platforms.py
+++ b/constants/ecp5_platforms.py
@@ -60,6 +60,7 @@ def named_pin(self, names: list[str]):
             if name in self.pin_bag:
                 self.pin_bag.remove(name)
                 return name
+        raise RuntimeError("Named pins %s not free" % ", ".join(names))
 
 
 ResourceBuilder: TypeAlias = Callable[[PinManager], list[Resource]]
@@ -124,8 +125,6 @@ class ECP5BG756Platform(LatticeECP5Platform):
         default_rst = "rst"
 
         clk_pin = pins.named_pin(ecp5_bg756_pclk)
-        if clk_pin is None:
-            raise RuntimeError("No free clk pin found.")
         resources = [
             Resource("rst", 0, PinsN(pins.p(), dir="i"), Attrs(IO_TYPE="LVCMOS33")),
             Resource("clk", 0, Pins(clk_pin, dir="i"), Clock(12e6), Attrs(IO_TYPE="LVCMOS33")),