Add a `gamepad` module for handling buttons in the background. (#295)

The `GamePad` singleton monitors buttons in the background to make sure a button press is never missed and debouncing happens consistently.

4 files changed, 236 insertions, 2 deletions

diff --git a/shared-bindings/gamepad/GamePad.c b/shared-bindings/gamepad/GamePad.c
new file mode 100644
index 000000000..bdc3359fb
--- /dev/null
+++ b/shared-bindings/gamepad/GamePad.c
@@ -0,0 +1,146 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Radomir Dopieralski for Adafruit Industries
+ *
+ * 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/obj.h"
+#include "py/runtime.h"
+#include "py/mphal.h"
+#include "shared-module/gamepad/GamePad.h"
+#include "GamePad.h"
+
+
+gamepad_obj_t* gamepad_singleton = NULL;
+
+//| .. currentmodule:: gamepad
+//|
+//| :class:`GamePad` -- Scan buttons for presses
+//| ============================================
+//|
+//| Usage::
+//|
+//|     import board
+//|     import digitalio
+//|     import gamepad
+//|     import time
+//|
+//|     B_UP = 1 << 0
+//|     B_DOWN = 1 << 1
+//|
+//|
+//|     pad = gamepad.GamePad(
+//|         digitalio.DigitalInOut(board.D0),
+//|         digitalio.DigitalInOut(board.D1),
+//|     )
+//|
+//|     y = 0
+//|     while True:
+//|         buttons = pad.get_pressed()
+//|         if buttons & B_UP:
+//|             y -= 1
+//|             print(y)
+//|         elif buttons & B_DOWN:
+//|             y += 1
+//|             print(y)
+//|         time.sleep(0.1)
+//|         while pad.get_pressed():
+//|             # Wait for all buttons to be released.
+//|             time.sleep(0.1)
+//|
+
+//| .. class:: GamePad([b1[, b2[, b3[, b4[, b5[, b6[, b7[, b8]]]]]]]])
+//|
+//|     Initializes button scanning routines.
+//|
+//|     The ``b1``-``b8`` parameters are ``DigitalInOut`` objects, which
+//|     immediately get switched to input with a pull-up, and then scanned
+//|     regularly for button presses. The order is the same as the order of
+//|     bits returned by the ``get_pressed`` function. You can re-initialize
+//|     it with different keys, then the new object will replace the previous
+//|     one.
+//|
+//|     The basic feature required here is the ability to poll the keys at
+//|     regular intervals (so that de-bouncing is consistent) and fast enough
+//|     (so that we don't miss short button presses) while at the same time
+//|     letting the user code run normally, call blocking functions and wait
+//|     on delays.
+//|
+//|     They button presses are accumulated, until the ``get_pressed`` method
+//|     is called, at which point the button state is cleared, and the new
+//|     button presses start to be recorded.
+//|
+STATIC mp_obj_t gamepad_make_new(const mp_obj_type_t *type, size_t n_args,
+        size_t n_kw, const mp_obj_t *args) {
+    if (!gamepad_singleton) {
+        gamepad_singleton = m_new_obj(gamepad_obj_t);
+        gamepad_singleton->base.type = &gamepad_type;
+    }
+    gamepad_init(n_args, args);
+    return MP_OBJ_FROM_PTR(gamepad_singleton);
+}
+
+
+//|     .. method:: get_pressed()
+//|
+//|         Get the status of buttons pressed since the last call and clear it.
+//|
+//|         Returns an 8-bit number, with bits that correspond to buttons,
+//|         which have been pressed (or held down) since the last call to this
+//|         function set to 1, and the remaining bits set to 0. Then it clears
+//|         the button state, so that new button presses (or buttons that are
+//|         held down) can be recorded for the next call.
+//|
+STATIC mp_obj_t gamepad_get_pressed(mp_obj_t self_in) {
+    gamepad_obj_t *self = MP_OBJ_TO_PTR(self_in);
+    mp_obj_t gamepad = MP_OBJ_NEW_SMALL_INT(self->pressed);
+    self->pressed = 0;
+    return gamepad;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(gamepad_get_pressed_obj, gamepad_get_pressed);
+
+
+//|     .. method:: deinit()
+//|
+//|         Disable button scanning.
+//|
+STATIC mp_obj_t gamepad_deinit(mp_obj_t self_in) {
+    gamepad_singleton = NULL;
+    return mp_const_none;
+}
+MP_DEFINE_CONST_FUN_OBJ_1(gamepad_deinit_obj, gamepad_deinit);
+
+
+STATIC mp_obj_t gamepad_make_new(const mp_obj_type_t *type, size_t n_args,
+        size_t n_kw, const mp_obj_t *args);
+STATIC const mp_rom_map_elem_t gamepad_locals_dict_table[] = {
+    { MP_OBJ_NEW_QSTR(MP_QSTR_get_pressed),  MP_ROM_PTR(&gamepad_get_pressed_obj)},
+    { MP_OBJ_NEW_QSTR(MP_QSTR_deinit),  MP_ROM_PTR(&gamepad_deinit_obj)},
+};
+STATIC MP_DEFINE_CONST_DICT(gamepad_locals_dict, gamepad_locals_dict_table);
+const mp_obj_type_t gamepad_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_GamePad,
+    .make_new = gamepad_make_new,
+    .locals_dict = (mp_obj_dict_t*)&gamepad_locals_dict,
+};
+
diff --git a/shared-bindings/gamepad/GamePad.h b/shared-bindings/gamepad/GamePad.h
new file mode 100644
index 000000000..172c95ace
--- /dev/null
+++ b/shared-bindings/gamepad/GamePad.h
@@ -0,0 +1,33 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Radomir Dopieralski for Adafruit Industries
+ *
+ * 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_SHARED_BINDINGS_GAMEPAD_GAMEPAD_H
+#define MICROPY_INCLUDED_SHARED_BINDINGS_GAMEPAD_GAMEPAD_H
+
+extern const mp_obj_type_t gamepad_type;
+
+#endif // MICROPY_INCLUDED_SHARED_BINDINGS_GAMEPAD_GAMEPAD_H
diff --git a/shared-bindings/gamepad/__init__.c b/shared-bindings/gamepad/__init__.c
new file mode 100644
index 000000000..0c99d0d52
--- /dev/null
+++ b/shared-bindings/gamepad/__init__.c
@@ -0,0 +1,54 @@
+/*
+ * This file is part of the MicroPython project, http://micropython.org/
+ *
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2016 Radomir Dopieralski for Adafruit Industries
+ *
+ * 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/obj.h"
+#include "py/runtime.h"
+#include "py/mphal.h"
+#include "GamePad.h"
+
+
+//| :mod:`gamepad` --- Button handling
+//| ==================================
+//|
+//| .. module:: gamepad
+//|   :synopsis: Button handling
+//|   :platform: SAMD21
+//|
+//| .. toctree::
+//|     :maxdepth: 3
+//|
+//|     GamePad
+//|
+STATIC const mp_rom_map_elem_t gamepad_module_globals_table[] = {
+    { MP_ROM_QSTR(MP_QSTR___name__), MP_ROM_QSTR(MP_QSTR_gamepad) },
+    { MP_OBJ_NEW_QSTR(MP_QSTR_GamePad),  MP_ROM_PTR(&gamepad_type)},
+};
+STATIC MP_DEFINE_CONST_DICT(gamepad_module_globals,
+        gamepad_module_globals_table);
+
+const mp_obj_module_t gamepad_module = {
+    .base = { &mp_type_module },
+    .globals = (mp_obj_dict_t*)&gamepad_module_globals,
+};
diff --git a/shared-bindings/index.rst b/shared-bindings/index.rst
index 49b6ce5bc..556626268 100644
--- a/shared-bindings/index.rst
+++ b/shared-bindings/index.rst
@@ -21,9 +21,10 @@ Module / Port      SAMD21   SAMD21 Express  ESP8266
 `board`            **Yes**  **Yes**         **Yes**
 `busio`            **Yes**  **Yes**         **Yes**
 `digitalio`        **Yes**  **Yes**         **Yes**
-`microcontroller`  **Yes**  **Yes**         **Yes**  
+`gamepad`          No       **Yes**         No
+`microcontroller`  **Yes**  **Yes**         **Yes**
 `multiterminal`    No       No              **Yes**
-`neopixel_write`   **Yes**  **Yes**         **Yes**  
+`neopixel_write`   **Yes**  **Yes**         **Yes**
 `nvm`              No       **Yes**         No
 `os`               **Yes**  **Yes**         **Yes**
 `pulseio`          No       **Yes**         No