refactor(dbus): Move ResetDriverWatchdog to process_image_helper.py

The ResetDriverWatchdog class was relocated from dbus_helper.py to a new
helper module, process_image_helper.py, to improve code organization
and maintainability. Updated imports in relevant files to reflect this
change.

src/revpi_middleware/dbus_middleware1/dbus_helper.py

@@ -1,17 +1,9 @@
 # -*- coding: utf-8 -*-
-# SPDX-FileCopyrightText: 2020-2023 Sven Sager
+# SPDX-FileCopyrightText: 2025 KUNBUS GmbH
 # SPDX-License-Identifier: GPL-2.0-or-later
-"""
+"""Helper for dbus."""
-Helper for the process image.
 
-The ResetDriverWatchdog class is a copy of revpipyload project module "watchdogs"
-https://github.com/naruxde/revpipyload/blob/b51c2b617a57cc7d96fd67e1da9f090a0624eacb/src/revpipyload/watchdogs.py
-"""
-
-import os
-from fcntl import ioctl
 from logging import getLogger
-from threading import Thread
 
 log = getLogger(__name__)
 
@@ -19,93 +11,6 @@ REVPI_DBUS_NAME = "com.revolutionpi.middleware1"
 REVPI_DBUS_BASE_PATH = "/com/revolutionpi/middleware1"
 
 
-class ResetDriverWatchdog(Thread):
-    """Watchdog to catch the reset_driver action."""
-
-    def __init__(self, pi_control_device="/dev/piControl0"):
-        super(ResetDriverWatchdog, self).__init__()
-        self.procimg = pi_control_device
-        self.daemon = True
-        self._calls = []
-        self._exit = False
-        self._fh = None
-        self.not_implemented = False
-        """True, if KB_WAIT_FOR_EVENT is not implemented in piControl."""
-        self._triggered = False
-        self.start()
-
-    def run(self):
-        """
-        Mainloop of watchdog for reset_driver.
-
-        If the thread can not open the process image or the IOCTL is not
-        implemented (wheezy), the thread function will stop. The trigger
-        property will always return True.
-        """
-        log.debug("enter ResetDriverWatchdog.run()")
-
-        try:
-            self._fh = os.open(self.procimg, os.O_RDONLY)
-        except Exception:
-            self.not_implemented = True
-            log.error(
-                "can not open process image at '{0}' for reset_driver watchdog"
-                "".format(self.procimg)
-            )
-            return
-
-        # The ioctl will return 2 byte (c-type int)
-        byte_buff = bytearray(2)
-        while not self._exit:
-            try:
-                rc = ioctl(self._fh, 19250, byte_buff)
-                if rc == 0 and byte_buff[0] == 1:
-                    self._triggered = True
-                    log.debug("reset_driver detected")
-                    for func in self._calls:
-                        func()
-            except Exception:
-                self.not_implemented = True
-                os.close(self._fh)
-                self._fh = None
-                log.warning("IOCTL KB_WAIT_FOR_EVENT is not implemented")
-                return
-
-        log.debug("leave ResetDriverWatchdog.run()")
-
-    def register_call(self, function):
-        """Register a function, if watchdog triggers."""
-        if not callable(function):
-            return ValueError("Function is not callable.")
-        if function not in self._calls:
-            self._calls.append(function)
-
-    def stop(self):
-        """Stop watchdog for reset_driver."""
-        log.debug("enter ResetDriverWatchdog.stop()")
-
-        self._exit = True
-        if self._fh is not None:
-            os.close(self._fh)
-            self._fh = None
-
-        log.debug("leave ResetDriverWatchdog.stop()")
-
-    def unregister_call(self, function=None):
-        """Remove a function call on watchdog trigger."""
-        if function is None:
-            self._calls.clear()
-        elif function in self._calls:
-            self._calls.remove(function)
-
-    @property
-    def triggered(self):
-        """Will return True one time after watchdog was triggered."""
-        rc = self._triggered
-        self._triggered = False
-        return rc
-
-
 def extend_interface(*args) -> str:
     """
     Extends an interface name by appending additional segments to a pre-defined base name.

src/revpi_middleware/dbus_middleware1/process_image/interface_picontrol.py

@@ -8,7 +8,7 @@ from logging import getLogger
 
 from pydbus.generic import signal
 
-from ..dbus_helper import ResetDriverWatchdog
+from .process_image_helper import ResetDriverWatchdog
 
 log = getLogger(__name__)
 

src/revpi_middleware/dbus_middleware1/process_image/process_image_helper.py

@@ -0,0 +1,102 @@
+# -*- coding: utf-8 -*-
+# SPDX-FileCopyrightText: 2025 KUNBUS GmbH
+# SPDX-License-Identifier: GPL-2.0-or-later
+"""
+Helper for the process image.
+
+The ResetDriverWatchdog class is a copy of revpipyload project module "watchdogs"
+https://github.com/naruxde/revpipyload/blob/b51c2b617a57cc7d96fd67e1da9f090a0624eacb/src/revpipyload/watchdogs.py
+"""
+import os
+from fcntl import ioctl
+from logging import getLogger
+from threading import Thread
+
+log = getLogger(__name__)
+
+
+class ResetDriverWatchdog(Thread):
+    """Watchdog to catch the reset_driver action."""
+
+    def __init__(self, pi_control_device="/dev/piControl0"):
+        super(ResetDriverWatchdog, self).__init__()
+        self.procimg = pi_control_device
+        self.daemon = True
+        self._calls = []
+        self._exit = False
+        self._fh = None
+        self.not_implemented = False
+        """True, if KB_WAIT_FOR_EVENT is not implemented in piControl."""
+        self._triggered = False
+        self.start()
+
+    def run(self):
+        """
+        Mainloop of watchdog for reset_driver.
+
+        If the thread cannot open the process image or the IOCTL is not
+        implemented (wheezy), the thread function will stop. The trigger
+        property will always return True.
+        """
+        log.debug("enter ResetDriverWatchdog.run()")
+
+        try:
+            self._fh = os.open(self.procimg, os.O_RDONLY)
+        except Exception:
+            self.not_implemented = True
+            log.error(
+                "can not open process image at '{0}' for reset_driver watchdog"
+                "".format(self.procimg)
+            )
+            return
+
+        # The ioctl will return 2 bytes (c-type int)
+        byte_buff = bytearray(2)
+        while not self._exit:
+            try:
+                rc = ioctl(self._fh, 19250, byte_buff)
+                if rc == 0 and byte_buff[0] == 1:
+                    self._triggered = True
+                    log.debug("reset_driver detected")
+                    for func in self._calls:
+                        func()
+            except Exception:
+                self.not_implemented = True
+                os.close(self._fh)
+                self._fh = None
+                log.warning("IOCTL KB_WAIT_FOR_EVENT is not implemented")
+                return
+
+        log.debug("leave ResetDriverWatchdog.run()")
+
+    def register_call(self, function):
+        """Register a function, if watchdog triggers."""
+        if not callable(function):
+            raise ValueError("Function is not callable.")
+        if function not in self._calls:
+            self._calls.append(function)
+
+    def stop(self):
+        """Stop watchdog for reset_driver."""
+        log.debug("enter ResetDriverWatchdog.stop()")
+
+        self._exit = True
+        if self._fh is not None:
+            os.close(self._fh)
+            self._fh = None
+
+        log.debug("leave ResetDriverWatchdog.stop()")
+
+    def unregister_call(self, function=None):
+        """Remove a function from the watchdog trigger."""
+        if function is None:
+            self._calls.clear()
+        elif function in self._calls:
+            self._calls.remove(function)
+
+    @property
+    def triggered(self):
+        """Will return True one time after watchdog was triggered."""
+        rc = self._triggered
+        self._triggered = False
+        return rc