There are currently 7 ports that implement machine.WDT and a lot of code is
duplicated across these implementations. This commit factors the common
parts of all these implementations to a single location in
extmod/machine_wdt.c. This common code provides the top-level Python
bindings (class and method wrappers), and then each port implements the
back end specific to that port.
With this refactor the ports remain functionally the same except for:
- The esp8266 WDT constructor now takes keyword arguments, and accepts the
"timeout" argument but raises an exception if it's not the default value
(this port doesn't support changing the timeout).
- The mimxrt and samd ports now interpret the argument to WDT.timeout_ms()
as signed and if it's negative truncate it to the minimum timeout (rather
than it being unsigned and a negative value truncating to the maximum
timeout).
Signed-off-by: Damien George <damien@micropython.org>
60929ec7e2