Add GamePadShift for handling shift-register-based buttons

6 files changed, 119 insertions, 17 deletions

diff --git a/shared-bindings/gamepad/GamePad.c b/shared-bindings/gamepad/GamePad.c
index 4458c972f..b211e229d 100644
--- a/shared-bindings/gamepad/GamePad.c
+++ b/shared-bindings/gamepad/GamePad.c
@@ -35,6 +35,15 @@
 #include "supervisor/shared/translate.h"
 #include "GamePad.h"
 
+digitalio_digitalinout_obj_t *validate_pin(mp_obj_t obj) {
+    if (!MP_OBJ_IS_TYPE(obj, &digitalio_digitalinout_type)) {
+        mp_raise_TypeError(translate("expected a DigitalInOut"));
+    }
+    digitalio_digitalinout_obj_t *pin = MP_OBJ_TO_PTR(obj);
+    raise_error_if_deinited(
+        common_hal_digitalio_digitalinout_deinited(pin));
+    return pin;
+}
 
 //| .. currentmodule:: gamepad
 //|
@@ -100,19 +109,52 @@ STATIC mp_obj_t gamepad_make_new(const mp_obj_type_t *type, size_t n_args,
         mp_raise_TypeError(translate("too many arguments"));
     }
     for (size_t i = 0; i < n_args; ++i) {
-        if (!MP_OBJ_IS_TYPE(args[i], &digitalio_digitalinout_type)) {
-            mp_raise_TypeError(translate("expected a DigitalInOut"));
-        }
-        digitalio_digitalinout_obj_t *pin = MP_OBJ_TO_PTR(args[i]);
-        raise_error_if_deinited(
-            common_hal_digitalio_digitalinout_deinited(pin));
+        validate_pin(args[i]);
+    }
+    if (!MP_STATE_VM(gamepad_singleton)) {
+        gamepad_obj_t* gamepad_singleton = m_new_obj(gamepad_obj_t);
+        gamepad_singleton->base.type = &gamepad_type;
+        MP_STATE_VM(gamepad_singleton) = gc_make_long_lived(gamepad_singleton);
     }
+    gamepad_init_pins(n_args, args);
+    return MP_OBJ_FROM_PTR(MP_STATE_VM(gamepad_singleton));
+}
+
+
+//| .. class:: GamePadShift(data, clock, latch)
+//|
+//|     Initializes button scanning routines.
+//|
+//|     The ``data``, ``clock`` and ``latch`` parameters are ``DigitalInOut``
+//|     objects connected to the shift register controlling the buttons.
+//|
+//|     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 gamepadshift_make_new(const mp_obj_type_t *type, size_t n_args,
+        const mp_obj_t *pos_args, mp_map_t *kw_args) {
+
+    enum { ARG_data, ARG_clock, ARG_latch };
+    static const mp_arg_t allowed_args[] = {
+        { MP_QSTR_data, MP_ARG_REQUIRED | MP_ARG_OBJ },
+        { MP_QSTR_clock, MP_ARG_REQUIRED | MP_ARG_OBJ},
+        { MP_QSTR_latch, MP_ARG_REQUIRED | MP_ARG_OBJ},
+    };
+    mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
+    mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args),
+                     allowed_args, args);
+
+    digitalio_digitalinout_obj_t *data_pin = validate_pin(args[ARG_data].u_obj);
+    digitalio_digitalinout_obj_t *clock_pin = validate_pin(args[ARG_clock].u_obj);
+    digitalio_digitalinout_obj_t *latch_pin = validate_pin(args[ARG_latch].u_obj);
+
     if (!MP_STATE_VM(gamepad_singleton)) {
         gamepad_obj_t* gamepad_singleton = m_new_obj(gamepad_obj_t);
         gamepad_singleton->base.type = &gamepad_type;
         MP_STATE_VM(gamepad_singleton) = gc_make_long_lived(gamepad_singleton);
     }
-    gamepad_init(n_args, args);
+    gamepad_init_shift(data_pin, clock_pin, latch_pin);
     return MP_OBJ_FROM_PTR(MP_STATE_VM(gamepad_singleton));
 }
 
@@ -158,3 +200,15 @@ const mp_obj_type_t gamepad_type = {
     .make_new = gamepad_make_new,
     .locals_dict = (mp_obj_dict_t*)&gamepad_locals_dict,
 };
+
+STATIC const mp_rom_map_elem_t gamepadshift_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(gamepadshift_locals_dict, gamepadshift_locals_dict_table);
+const mp_obj_type_t gamepadshift_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_GamePadShift,
+    .make_new = gamepadshift_make_new,
+    .locals_dict = (mp_obj_dict_t*)&gamepadshift_locals_dict,
+};
diff --git a/shared-bindings/gamepad/GamePad.h b/shared-bindings/gamepad/GamePad.h
index 172c95ace..350331193 100644
--- a/shared-bindings/gamepad/GamePad.h
+++ b/shared-bindings/gamepad/GamePad.h
@@ -29,5 +29,6 @@
 #define MICROPY_INCLUDED_SHARED_BINDINGS_GAMEPAD_GAMEPAD_H
 
 extern const mp_obj_type_t gamepad_type;
+extern const mp_obj_type_t gamepadshift_type;
 
 #endif // MICROPY_INCLUDED_SHARED_BINDINGS_GAMEPAD_GAMEPAD_H
diff --git a/shared-bindings/gamepad/__init__.c b/shared-bindings/gamepad/__init__.c
index 0c99d0d52..0775d6abf 100644
--- a/shared-bindings/gamepad/__init__.c
+++ b/shared-bindings/gamepad/__init__.c
@@ -44,6 +44,7 @@
 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)},
+    { MP_OBJ_NEW_QSTR(MP_QSTR_GamePadShift),  MP_ROM_PTR(&gamepadshift_type)},
 };
 STATIC MP_DEFINE_CONST_DICT(gamepad_module_globals,
         gamepad_module_globals_table);
diff --git a/shared-module/gamepad/GamePad.c b/shared-module/gamepad/GamePad.c
index 2c14fa02a..ed574db53 100644
--- a/shared-module/gamepad/GamePad.c
+++ b/shared-module/gamepad/GamePad.c
@@ -35,7 +35,7 @@
 #include "shared-bindings/util.h"
 
 
-void gamepad_init(size_t n_pins, const mp_obj_t* pins) {
+void gamepad_init_pins(size_t n_pins, const mp_obj_t* pins) {
     gamepad_obj_t* gamepad_singleton = MP_STATE_VM(gamepad_singleton);
     for (size_t i = 0; i < 8; ++i) {
         gamepad_singleton->pins[i] = NULL;
@@ -57,4 +57,23 @@ void gamepad_init(size_t n_pins, const mp_obj_t* pins) {
         gamepad_singleton->pins[i] = pin;
     }
     gamepad_singleton->last = 0;
+    gamepad_singleton->kind = GAMEPAD_KIND_PINS;
+}
+
+void gamepad_init_shift(digitalio_digitalinout_obj_t *data_pin,
+                        digitalio_digitalinout_obj_t *clock_pin,
+                        digitalio_digitalinout_obj_t *latch_pin) {
+    gamepad_obj_t* gamepad_singleton = MP_STATE_VM(gamepad_singleton);
+
+    common_hal_digitalio_digitalinout_switch_to_input(data_pin, PULL_NONE);
+    gamepad_singleton->pins[0] = data_pin;
+
+    common_hal_digitalio_digitalinout_switch_to_output(clock_pin, 0, DRIVE_MODE_PUSH_PULL);
+    gamepad_singleton->pins[1] = clock_pin;
+
+    common_hal_digitalio_digitalinout_switch_to_output(clock_pin, 1, DRIVE_MODE_PUSH_PULL);
+    gamepad_singleton->pins[2] = latch_pin;
+
+    gamepad_singleton->last = 0;
+    gamepad_singleton->kind = GAMEPAD_KIND_PINS;
 }
diff --git a/shared-module/gamepad/GamePad.h b/shared-module/gamepad/GamePad.h
index 9fd5c9626..9bc5a711c 100644
--- a/shared-module/gamepad/GamePad.h
+++ b/shared-module/gamepad/GamePad.h
@@ -37,8 +37,15 @@ typedef struct {
     volatile uint8_t last;
     volatile uint8_t pressed;
     uint8_t pulls;
+    uint8_t kind;
 } gamepad_obj_t;
 
-void gamepad_init(size_t n_pins, const mp_obj_t* pins);
+#define GAMEPAD_KIND_PINS 0
+#define GAMEPAD_KIND_SHIFT 1
+
+void gamepad_init_pins(size_t n_pins, const mp_obj_t* pins);
+void gamepad_init_shift(digitalio_digitalinout_obj_t *data_pin,
+                        digitalio_digitalinout_obj_t *clock_pin,
+                        digitalio_digitalinout_obj_t *latch_pin);
 
 #endif  // MICROPY_INCLUDED_GAMEPAD_GAMEPAD_H
diff --git a/shared-module/gamepad/__init__.c b/shared-module/gamepad/__init__.c
index 8414ddfbe..c79ee30ba 100644
--- a/shared-module/gamepad/__init__.c
+++ b/shared-module/gamepad/__init__.c
@@ -40,17 +40,37 @@ void gamepad_tick(void) {
     }
     uint8_t gamepad_current = 0;
     uint8_t bit = 1;
-    for (int i = 0; i < 8; ++i) {
-        digitalio_digitalinout_obj_t* pin = gamepad_singleton->pins[i];
-        if (!pin) {
-            break;
+    switch (gamepad_singleton->kind) {
+    case GAMEPAD_KIND_PINS:
+        for (int i = 0; i < 8; ++i) {
+            digitalio_digitalinout_obj_t* pin = gamepad_singleton->pins[i];
+            if (!pin) {
+                break;
+            }
+            if (common_hal_digitalio_digitalinout_get_value(pin)) {
+                gamepad_current |= bit;
+            }
+            bit <<= 1;
         }
-        if (common_hal_digitalio_digitalinout_get_value(pin)) {
-            gamepad_current |= bit;
+        gamepad_current ^= gamepad_singleton->pulls;
+        break;
+    case GAMEPAD_KIND_SHIFT:
+        bit = 1;
+        digitalio_digitalinout_obj_t* data_pin = gamepad_singleton->pins[0];
+        digitalio_digitalinout_obj_t* clock_pin = gamepad_singleton->pins[1];
+        digitalio_digitalinout_obj_t* latch_pin = gamepad_singleton->pins[2];
+        common_hal_digitalio_digitalinout_set_value(latch_pin, 0);
+        for (int i = 0; i < 8; ++i) {
+            common_hal_digitalio_digitalinout_set_value(clock_pin, 1);
+            if (common_hal_digitalio_digitalinout_get_value(data_pin)) {
+                gamepad_current |= bit;
+            }
+            bit <<= 1;
+            common_hal_digitalio_digitalinout_set_value(clock_pin, 0);
         }
-        bit <<= 1;
+        common_hal_digitalio_digitalinout_set_value(latch_pin, 1);
+        break;
     }
-    gamepad_current ^= gamepad_singleton->pulls;
     gamepad_singleton->pressed |= gamepad_singleton->last & gamepad_current;
     gamepad_singleton->last = gamepad_current;
 }