Add patch saving and loading

app/open-nsynth/.gitignore

@@ -1,3 +1,4 @@
 /bin/data/localSettings.json
+/bin/data/patches.json
 /bin/open-nsynth
 /obj

app/open-nsynth/src/AnalogInput.cpp

@@ -22,17 +22,21 @@ void AnalogInput::init(uint8_t value){
 }
 
 
-bool AnalogInput::update(uint8_t value, bool currentScreen){
-	int8_t delta = abs(static_cast<int8_t>(value - displayedValue));
+bool AnalogInput::update(uint8_t value, bool software, bool currentScreen){
 	bool changed;
 
-	if(currentScreen){
-		changed = delta > CURRENT_SCREEN_DELTA;
+	if(software){
+		changed = value != displayedValue;
 	}else{
-		changed = delta > HIDDEN_SCREEN_DELTA;
+		int delta = abs(int(value) - int(readValue));
+		if(currentScreen){
+			changed = delta > CURRENT_SCREEN_DELTA;
+		}else{
+			changed = delta > HIDDEN_SCREEN_DELTA;
+		}
+		readValue = value;
 	}
 
-	readValue = value;
 	if(changed){
 		displayedValue = value;
 	}

app/open-nsynth/src/AnalogInput.h

@@ -24,9 +24,9 @@ class AnalogInput{
 
 		// Updates the value.
 		// Returns true if the value has changed more than a threshold.
-		bool update(uint8_t value, bool currentScreen);
+		bool update(uint8_t value, bool software, bool currentScreen=false);
 
-		// Returns the value as a float in the range 0.0 - 1.0.
+		// Returns the displayedValue as a float in the range 0.0 - 1.0.
 		float getNormalized() const;
 
 		static constexpr int CURRENT_SCREEN_DELTA = 2;

app/open-nsynth/src/Gpio.cpp

@@ -0,0 +1,124 @@
+/*
+Copyright 2017 Google Inc. All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include "Gpio.h"
+
+#include <chrono>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/mman.h>
+#include <thread>
+#include <unistd.h>
+
+
+constexpr int SET = 7;
+constexpr int CLEAR = 10;
+constexpr int GET = 13;
+constexpr int MAP_SIZE = 0xb4;
+constexpr int GPPUD = 37;
+constexpr int GPPUDCLK = 38;
+
+
+Gpio::Gpio(){
+	int fd = open("/dev/gpiomem", O_RDWR | O_SYNC);
+	if(fd >= 0){
+		gpioReg = (uint32_t *)mmap(
+				NULL, MAP_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+
+		if(gpioReg == MAP_FAILED){
+			gpioReg = nullptr;
+		}
+
+		close(fd);
+	}
+}
+
+
+Gpio::~Gpio(){
+	if(gpioReg){
+		munmap(const_cast<uint32_t *>(gpioReg), MAP_SIZE);
+	}
+}
+
+
+Gpio::operator bool() const{
+	return gpioReg != nullptr;
+}
+
+
+bool Gpio::setInput(int pin, Pull pull){
+	if(!gpioReg || pin < 2 || pin > 27){
+		return false;
+	}
+
+	int reg = pin / 10;
+	int shift = (pin % 10) * 3;
+
+	gpioReg[reg] = (gpioReg[reg] & ~(7<<shift));
+
+	gpioReg[GPPUD] = pull & 3;
+	std::this_thread::sleep_for(std::chrono::milliseconds(1));
+	gpioReg[GPPUDCLK] = 1 << pin;
+	std::this_thread::sleep_for(std::chrono::milliseconds(1));
+
+	gpioReg[GPPUD] = 0;
+	gpioReg[GPPUDCLK] = 0;
+
+	return true;
+}
+
+
+bool Gpio::setOutput(int pin){
+	if(!gpioReg || pin < 2 || pin > 27){
+		return false;
+	}
+
+	int reg = pin / 10;
+	int shift = (pin % 10) * 3;
+
+	gpioReg[reg] = (gpioReg[reg] & ~(7<<shift)) | (1<<shift);
+
+	return true;
+}
+
+
+bool Gpio::write(int pin, bool high){
+	if(!gpioReg || pin < 2 || pin > 27){
+		return false;
+	}
+
+	gpioReg[high ? SET : CLEAR] = 1 << (pin & 0x1f);
+	return true;
+}
+
+
+bool Gpio::read(int pin){
+	if(!gpioReg || pin < 2 || pin > 27){
+		return false;
+	}
+
+	return (gpioReg[GET] & (1 << (pin & 0x1f))) != 0;
+}
+
+
+void Gpio::reset(int pin, size_t uSecHold, size_t uSecDelay){
+	// Set the pin to an output and drive it low.
+	setOutput(pin);
+	write(pin, false);
+	std::this_thread::sleep_for(std::chrono::microseconds(uSecHold));
+
+	// Restore the pin
+	write(pin, 1);
+	setInput(pin, PULL_UP);
+	std::this_thread::sleep_for(std::chrono::microseconds(uSecDelay));
+}

app/open-nsynth/src/Gpio.h

@@ -0,0 +1,45 @@
+/*
+Copyright 2017 Google Inc. All Rights Reserved.
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+    http://www.apache.org/licenses/LICENSE-2.0
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#pragma once
+
+#include <cstddef>
+#include <stdint.h>
+
+
+// Provides access to the GPIO pins on a Raspberry Pi
+class Gpio{
+	public:
+		enum Pull{
+			PULL_NONE=0,
+			PULL_DOWN,
+			PULL_UP
+		};
+
+		Gpio();
+		~Gpio();
+
+		operator bool() const;
+
+		bool setInput(int pin, Pull pull=PULL_NONE);
+		bool setOutput(int pin);
+
+		bool write(int pin, bool high);
+		bool read(int pin);
+
+		// Sends a reset signal by pulsing a pin low.
+		void reset(int pin, size_t uSecHold, size_t uSecDelay);
+
+	protected:
+		volatile uint32_t *gpioReg = nullptr;
+};

app/open-nsynth/src/OledScreenDriver.cpp

@@ -20,7 +20,7 @@ limitations under the License.
 #include <unistd.h>
 
 
-bool OledScreenDriver::setup(int i2cFd_, uint8_t address_, int resetPin){
+bool OledScreenDriver::setup(int i2cFd_, uint8_t address_){
 	i2cFd = i2cFd_;
 	address = address_;
 
@@ -31,10 +31,7 @@ bool OledScreenDriver::setup(int i2cFd_, uint8_t address_, int resetPin){
 		return false;
 	}
 
-	// First use the reset pin to reset the screen.
-	reset(resetPin);
-
-	// Now send the screen setup commands.
+	// Send the screen setup commands.
 	static uint8_t setup0[] = {
 		0, 174, 213, 128, 168, 63, 211, 0, 64, 141, 20, 32,
 		0, 161, 200, 218, 18, 217, 241, 219, 64, 164, 166
@@ -110,62 +107,3 @@ void OledScreenDriver::draw(ofFbo &fbo){
 		return;
 	}
 }
-
-
-void OledScreenDriver::reset(int resetPin){
-	constexpr int INPUT = 1;
-	constexpr int OUTPUT = 1;
-	constexpr int SET = 7;
-	constexpr int CLEAR = 10;
-	constexpr int MAP_SIZE = 0xb4;
-
-	if(resetPin < 0){
-		return;
-	}
-
-	// Mmap the GPIO device to access the pins.
-	int fd = open("/dev/gpiomem", O_RDWR | O_SYNC);
-	if(fd < 0){
-		return;
-	}
-
-	volatile uint32_t *gpioReg = (uint32_t *)mmap(
-			NULL, MAP_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
-
-	close(fd);
-
-	if(gpioReg == MAP_FAILED){
-		return;
-	}
-
-	// Sets the mode to either INPUT or OUTPUT.
-	auto setMode = [&](int mode){
-		int reg = resetPin / 10;
-		int shift = (resetPin % 10) * 3;
-
-		gpioReg[reg] = (gpioReg[reg] & ~(7<<shift)) | (mode<<shift);
-	};
-
-	// Sets the level to high (1) or low (0).
-	auto writeLevel = [&](int level){
-		int bank = resetPin >> 5;
-		int val = 1 << (resetPin & 0x1f);
-		if(level){
-			gpioReg[bank+SET] = val;
-		}else{
-			gpioReg[bank+CLEAR] = val;
-		}
-	};
-
-	// Drive the reset pin low for 1ms.
-	setMode(OUTPUT);
-	writeLevel(0);
-	usleep(1000);
-	writeLevel(1);
-
-	// Then change it back to an input and wait for the screen to initialise.
-	setMode(INPUT);
-	usleep(1000);
-
-	munmap(const_cast<uint32_t *>(gpioReg), MAP_SIZE);
-}

app/open-nsynth/src/OledScreenDriver.h

@@ -14,19 +14,18 @@ limitations under the License.
 #pragma once
 
 #include "ofMain.h"
+#include "Gpio.h"
 
 
 // Drives the SSD1306 based screen over I2C.
 class OledScreenDriver{
 	public:
 		// Sends the initial configuration to the screen.
-		bool setup(int i2cFd, uint8_t address, int resetPin=-1);
+		bool setup(int i2cFd, uint8_t address);
 		// Draws a 128x64 frame buffer on the screen.
 		void draw(ofFbo &fbo);
 
 	private:
-		// Resets the screen by driving a GPIO reset pin low.
-		void reset(int resetPin);
 		// The file descriptor of the I2C device.
 		int i2cFd;
 		// The I2C address of the screen.