From 52d05bbc37d063a1fdc359b18b9b112665f92276 Mon Sep 17 00:00:00 2001
From: Radomir Dopieralski <openstack@sheep.art.pl>
Date: Wed, 23 May 2018 11:26:16 +0200
Subject: Cache pullup state in gamepad

Don't check the pin's pull direction on every tick, instead cache it
at the beginning. Also avoid a "can't get pull of output pin" error
when one of the pins passed is in output mode.
---
 shared-bindings/gamepad/GamePad.c |  2 +-
 shared-module/gamepad/GamePad.c   | 11 +++++++++--
 shared-module/gamepad/GamePad.h   |  3 ++-
 shared-module/gamepad/__init__.c  | 11 ++++++-----
 4 files changed, 18 insertions(+), 9 deletions(-)

diff --git a/shared-bindings/gamepad/GamePad.c b/shared-bindings/gamepad/GamePad.c
index d80d1fcf6..43efc3b18 100644
--- a/shared-bindings/gamepad/GamePad.c
+++ b/shared-bindings/gamepad/GamePad.c
@@ -31,7 +31,7 @@
 #include "GamePad.h"
 
 
-gamepad_obj_t* gamepad_singleton = NULL;
+gamepad_obj_t* volatile gamepad_singleton = NULL;
 
 //| .. currentmodule:: gamepad
 //|
diff --git a/shared-module/gamepad/GamePad.c b/shared-module/gamepad/GamePad.c
index cd1df9b57..540c882da 100644
--- a/shared-module/gamepad/GamePad.c
+++ b/shared-module/gamepad/GamePad.c
@@ -38,14 +38,21 @@ void gamepad_init(size_t n_pins, const mp_obj_t* pins) {
     for (size_t i=0; i<8; ++i) {
         gamepad_singleton->pins[i] = NULL;
     }
+    gamepad_singleton->pulls = 0;
     for (size_t i=0; i<n_pins; ++i) {
         digitalio_digitalinout_obj_t *pin = MP_OBJ_TO_PTR(pins[i]);
         raise_error_if_deinited(common_hal_digitalio_digitalinout_deinited(pin));
         digitalio_direction_t direction = common_hal_digitalio_digitalinout_get_direction(pin);
-        digitalio_pull_t pull = common_hal_digitalio_digitalinout_get_pull(pin);
-        if (direction != DIRECTION_INPUT || pull == PULL_NONE) {
+        if (direction != DIRECTION_INPUT) {
             common_hal_digitalio_digitalinout_switch_to_input(pin, PULL_UP);
         }
+        digitalio_pull_t pull = common_hal_digitalio_digitalinout_get_pull(pin);
+        if (pull == PULL_NONE) {
+            common_hal_digitalio_digitalinout_set_pull(pin, PULL_UP);
+        }
+        if (pull != PULL_DOWN) {
+            gamepad_singleton->pulls |= 1 << i;
+        }
         gamepad_singleton->pins[i] = pin;
     }
     gamepad_singleton->last = 0;
diff --git a/shared-module/gamepad/GamePad.h b/shared-module/gamepad/GamePad.h
index e5f709134..77fdb8b0a 100644
--- a/shared-module/gamepad/GamePad.h
+++ b/shared-module/gamepad/GamePad.h
@@ -36,9 +36,10 @@ typedef struct {
     digitalio_digitalinout_obj_t* pins[8];
     volatile uint8_t last;
     volatile uint8_t pressed;
+    uint8_t pulls;
 } gamepad_obj_t;
 
-extern gamepad_obj_t* gamepad_singleton;
+extern gamepad_obj_t* volatile gamepad_singleton;
 
 void gamepad_init(size_t n_pins, const mp_obj_t* pins);
 
diff --git a/shared-module/gamepad/__init__.c b/shared-module/gamepad/__init__.c
index 591a2fa0a..b1cdac2a7 100644
--- a/shared-module/gamepad/__init__.c
+++ b/shared-module/gamepad/__init__.c
@@ -37,17 +37,18 @@ void gamepad_tick(void) {
         return;
     }
     uint8_t gamepad_current = 0;
-    for (int i=0; i<8; ++i) {
+    uint8_t bit = 1;
+    for (int i = 0; i < 8; ++i) {
         digitalio_digitalinout_obj_t* pin = gamepad_singleton->pins[i];
         if (!pin) {
             break;
         }
-        digitalio_pull_t pull = common_hal_digitalio_digitalinout_get_pull(pin);
-        bool value = common_hal_digitalio_digitalinout_get_value(pin);
-        if ((pull == PULL_UP && !value) || (pull == PULL_DOWN && value)) {
-            gamepad_current |= 1 << i;
+        if (common_hal_digitalio_digitalinout_get_value(pin)) {
+            gamepad_current |= bit;
         }
+        bit <<= 1;
     }
+    gamepad_current ^= gamepad_singleton->pulls;
     gamepad_singleton->pressed |= gamepad_singleton->last & gamepad_current;
     gamepad_singleton->last = gamepad_current;
 }
-- 
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