From e19b2b9085d42df5790103d9dd8bd388f5fea16a Mon Sep 17 00:00:00 2001
From: Romain Goyet <romain.goyet@numworks.com>
Date: Fri, 31 Mar 2017 17:59:34 +0200
Subject: [PATCH] [ion] Add a Display::waitForVBlank method

Change-Id: Ie744ec4a73eeb7c2d7c549fd7f47ff4c74aab5ee
---
 ion/include/ion/display.h  |  2 ++
 ion/src/device/display.cpp | 19 +++++++++++++++++++
 ion/src/device/display.h   |  2 ++
 ion/src/simulator/init.cpp |  3 +++
 4 files changed, 26 insertions(+)

diff --git a/ion/include/ion/display.h b/ion/include/ion/display.h
index cd6412586..4db471ba7 100644
--- a/ion/include/ion/display.h
+++ b/ion/include/ion/display.h
@@ -21,6 +21,8 @@ void pushRect(KDRect r, const KDColor * pixels);
 void pushRectUniform(KDRect r, KDColor c);
 void pullRect(KDRect r, KDColor * pixels);
 
+void waitForVBlank();
+
 constexpr int Width = 320;
 constexpr int Height = 240;
 
diff --git a/ion/src/device/display.cpp b/ion/src/device/display.cpp
index 1b479ecfa..a3732c9d2 100644
--- a/ion/src/device/display.cpp
+++ b/ion/src/device/display.cpp
@@ -31,6 +31,18 @@ void pullRect(KDRect r, KDColor * pixels) {
   Device::pullPixels(pixels, r.width()*r.height());
 }
 
+void waitForVBlank() {
+  // We want to return as soon as the TE line is transitionning from "DOWN" to "UP"
+  while (Device::TearingEffectPin.group().IDR()->get(Device::TearingEffectPin.pin())) {
+    // Loop while high, exit when low
+    // Wait for zero
+  }
+  while (!Device::TearingEffectPin.group().IDR()->get(Device::TearingEffectPin.pin())) {
+    // Loop while low, exit when high
+  }
+  // Here, we went from low to high
+}
+
 }
 }
 
@@ -69,6 +81,10 @@ void initGPIO() {
   ResetPin.group().MODER()->setMode(ResetPin.pin(), GPIO::MODER::Mode::Output);
   ResetPin.group().ODR()->set(ResetPin.pin(), true);
 
+  // Turn on the Tearing Effect pin
+  TearingEffectPin.group().MODER()->setMode(TearingEffectPin.pin(), GPIO::MODER::Mode::Input);
+  TearingEffectPin.group().PUPDR()->setPull(TearingEffectPin.pin(), GPIO::PUPDR::Pull::None);
+
   msleep(120);
 }
 
@@ -86,6 +102,8 @@ void shutdownGPIO() {
 
   PowerPin.group().MODER()->setMode(PowerPin.pin(), GPIO::MODER::Mode::Analog);
   PowerPin.group().PUPDR()->setPull(PowerPin.pin(), GPIO::PUPDR::Pull::None);
+
+  TearingEffectPin.group().MODER()->setMode(TearingEffectPin.pin(), GPIO::MODER::Mode::Analog);
 }
 
 void initFSMC() {
@@ -173,6 +191,7 @@ void initPanel() {
 
   SEND_COMMAND(PixelFormatSet, 0x05);
   SEND_COMMAND(MemoryAccessControl, 0xA0);
+  SEND_COMMAND(TearingEffectLineOn, 0x00);
 
   *CommandAddress = Command::DisplayOn;
   //msleep(50);
diff --git a/ion/src/device/display.h b/ion/src/device/display.h
index 63b31d2c2..46c744ea5 100644
--- a/ion/src/device/display.h
+++ b/ion/src/device/display.h
@@ -64,6 +64,7 @@ enum class Command : uint16_t {
   PageAddressSet = 0x2B,
   MemoryWrite = 0x2C,
   MemoryRead = 0x2E,
+  TearingEffectLineOn = 0x35,
   MemoryAccessControl = 0x36,
   PixelFormatSet = 0x3A,
 };
@@ -79,6 +80,7 @@ constexpr static GPIOPin FSMCPins[] = {
 
 constexpr static GPIOPin PowerPin = GPIOPin(GPIOB, 14);
 constexpr static GPIOPin ResetPin = GPIOPin(GPIOE, 9);
+constexpr static GPIOPin TearingEffectPin = GPIOPin(GPIOB, 10);
 
 constexpr static int FSMCMemoryBank = 1;
 constexpr static int FSMCDataCommandAddressBit = 16;
diff --git a/ion/src/simulator/init.cpp b/ion/src/simulator/init.cpp
index 10dbf48cc..1b92fcd8f 100644
--- a/ion/src/simulator/init.cpp
+++ b/ion/src/simulator/init.cpp
@@ -58,6 +58,9 @@ void Ion::Display::pullRect(KDRect r, KDColor * pixels) {
   sFrameBuffer->pullRect(r, pixels);
 }
 
+void Ion::Display::waitForVBlank() {
+}
+
 Ion::Keyboard::State Ion::Keyboard::scan() {
   Ion::Keyboard::State result = 0;
   for (int i=0; i<Ion::Keyboard::NumberOfKeys; i++) {