extmod/machine_wdt: Factor ports' WDT Python bindings to common code.

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>

extmod/extmod.cmake

@@ -14,6 +14,7 @@ set(MICROPY_SOURCE_EXTMOD
     ${MICROPY_EXTMOD_DIR}/machine_pwm.c
     ${MICROPY_EXTMOD_DIR}/machine_signal.c
     ${MICROPY_EXTMOD_DIR}/machine_spi.c
+    ${MICROPY_EXTMOD_DIR}/machine_wdt.c
     ${MICROPY_EXTMOD_DIR}/modbluetooth.c
     ${MICROPY_EXTMOD_DIR}/modframebuf.c
     ${MICROPY_EXTMOD_DIR}/modlwip.c

extmod/extmod.mk

@@ -11,6 +11,7 @@ SRC_EXTMOD_C += \
 	extmod/machine_signal.c \
 	extmod/machine_spi.c \
 	extmod/machine_timer.c \
+	extmod/machine_wdt.c \
 	extmod/modasyncio.c \
 	extmod/modbinascii.c \
 	extmod/modbluetooth.c \

extmod/machine_wdt.c

@@ -0,0 +1,95 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2020-2023 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "py/runtime.h"
+
+#if MICROPY_PY_MACHINE_WDT
+
+#include "extmod/modmachine.h"
+
+// The port must provide implementations of these low-level WDT functions.
+STATIC machine_wdt_obj_t *mp_machine_wdt_make_new_instance(mp_int_t id, mp_int_t timeout_ms);
+STATIC void mp_machine_wdt_feed(machine_wdt_obj_t *self);
+#if MICROPY_PY_MACHINE_WDT_TIMEOUT_MS
+STATIC void mp_machine_wdt_timeout_ms_set(machine_wdt_obj_t *self_in, mp_int_t timeout_ms);
+#endif
+
+// The port provides implementations of the above in this file.
+#include MICROPY_PY_MACHINE_WDT_INCLUDEFILE
+
+STATIC mp_obj_t machine_wdt_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *all_args) {
+    enum { ARG_id, ARG_timeout };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_id, MP_ARG_INT, {.u_int = 0} },
+        { MP_QSTR_timeout, MP_ARG_INT, {.u_int = 5000} },
+    };
+
+    // Parse the arguments.
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all_kw_array(n_args, n_kw, all_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
+
+    // Create WDT instance.
+    machine_wdt_obj_t *self = mp_machine_wdt_make_new_instance(args[ARG_id].u_int, args[ARG_timeout].u_int);
+
+    return MP_OBJ_FROM_PTR(self);
+}
+
+// WDT.feed()
+STATIC mp_obj_t machine_wdt_feed(mp_obj_t self_in) {
+    machine_wdt_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_machine_wdt_feed(self);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_wdt_feed_obj, machine_wdt_feed);
+
+#if MICROPY_PY_MACHINE_WDT_TIMEOUT_MS
+// WDT.timeout_ms(timeout)
+STATIC mp_obj_t machine_wdt_timeout_ms(mp_obj_t self_in, mp_obj_t timeout_in) {
+    machine_wdt_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_int_t timeout_ms = mp_obj_get_int(timeout_in);
+    mp_machine_wdt_timeout_ms_set(self, timeout_ms);
+    return mp_const_none;
+}
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(machine_wdt_timeout_ms_obj, machine_wdt_timeout_ms);
+#endif
+
+STATIC const mp_rom_map_elem_t machine_wdt_locals_dict_table[] = {
+    { MP_ROM_QSTR(MP_QSTR_feed), MP_ROM_PTR(&machine_wdt_feed_obj) },
+    #if MICROPY_PY_MACHINE_WDT_TIMEOUT_MS
+    { MP_ROM_QSTR(MP_QSTR_timeout_ms), MP_ROM_PTR(&machine_wdt_timeout_ms_obj) },
+    #endif
+};
+STATIC MP_DEFINE_CONST_DICT(machine_wdt_locals_dict, machine_wdt_locals_dict_table);
+
+MP_DEFINE_CONST_OBJ_TYPE(
+    machine_wdt_type,
+    MP_QSTR_WDT,
+    MP_TYPE_FLAG_NONE,
+    make_new, machine_wdt_make_new,
+    locals_dict, &machine_wdt_locals_dict
+    );
+
+#endif // MICROPY_PY_MACHINE_WDT

extmod/modmachine.h

@@ -0,0 +1,43 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2023 Damien P. George
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef MICROPY_INCLUDED_EXTMOD_MODMACHINE_H
+#define MICROPY_INCLUDED_EXTMOD_MODMACHINE_H
+
+#include "py/obj.h"
+
+// A port must provide these types, but they are otherwise opaque.
+typedef struct _machine_wdt_obj_t machine_wdt_obj_t;
+
+// These classes correspond to machine.Type entries in the machine module.
+// Their Python bindings are implemented in extmod, and their implementation
+// is provided by a port.
+extern const mp_obj_type_t machine_i2c_type;
+extern const mp_obj_type_t machine_spi_type;
+extern const mp_obj_type_t machine_timer_type;
+extern const mp_obj_type_t machine_wdt_type;
+
+#endif // MICROPY_INCLUDED_EXTMOD_MODMACHINE_H