MMIO.write raises ValueError for IntEnum/IntFlag values

[gweesip]

• PYNQ version: all current versions
• Board name: any, pure Python issue
• Pull request type: bug fix
• Pull request number: N/A
• Description:

MMIO.write uses type(data) is int to check whether the supplied data is an integer, which excludes IntEnum and IntFlag values despite them being fully int-compatible (isinstance(data, int) returns True for both). This means that passing an IntEnum or IntFlag value directly raises a ValueError: Data type must be int or bytes, requiring an explicit int() cast at the call site as a workaround.

Reproduction:

from enum import IntEnum
from pynq import MMIO

class MyReg(IntEnum):
    ENABLE = 1

mmio = MMIO(0x40000000, 0x1000)
mmio.write(0x0, MyReg.ENABLE)      # raises ValueError: Data type must be int or bytes.
mmio.write(0x0, int(MyReg.ENABLE)) # workaround

The relevant check in mmio.py:

if type(data) is int:
    self.array[idx] = data
elif type(data) is bytes:
    self._hook.write(offset, data)
else:
    raise ValueError("Data type must be int or bytes.")

The numpy assignment (self.array[idx] = np.uint32(data)) on the integer path handles IntEnum/IntFlag values without issue, so there is no technical reason to exclude them. The fix is to replace the strict identity checks with isinstance checks:

if isinstance(data, int):
    self.array[idx] = data
elif isinstance(data, bytes):
    self._hook.write(offset, data)
else:
    raise ValueError("Data type must be int or bytes.")

This is consistent with Python's duck-typing conventions and would allow IntEnum and IntFlag values to be passed without requiring the caller to manually cast them.