Add WM8960 support (#133)

Patch in WM8960 support by using Circle ae22928 from the develop branch
Thanks @matemaciek and @rsta2

.github/workflows/build.yml

@@ -20,6 +20,12 @@ jobs:
       run: |
            set -ex
            git submodule update --init --recursive
+    - name: Use Circle develop branch for WM8960 support until it is merged upstream
+      run: |
+           set -ex
+           cd circle-stdlib/libs/circle
+           git checkout ae22928 # develop
+           cd -
     - name: Install toolchains
       run: |
            set -ex

src/patches/WM8960.diff

@@ -0,0 +1,182 @@
+diff --git a/include/circle/i2ssoundbasedevice.h b/include/circle/i2ssoundbasedevice.h
+index 3cfe21a3..39dea460 100644
+--- a/include/circle/i2ssoundbasedevice.h
++++ b/include/circle/i2ssoundbasedevice.h
+@@ -26,6 +26,7 @@
+ #include <circle/gpiopin.h>
+ #include <circle/gpioclock.h>
+ #include <circle/dmasoundbuffers.h>
++#include <circle/logger.h>
+ #include <circle/types.h>
+ 
+ class CI2SSoundBaseDevice : public CSoundBaseDevice	/// Low level access to the I2S sound device
+@@ -98,7 +99,10 @@ class CI2SSoundBaseDevice : public CSoundBaseDevice	/// Low level access to the
+ 	static unsigned RXCompletedHandler (boolean bStatus, u32 *pBuffer,
+ 					    unsigned nChunkSize, void *pParam);
+ 
+-	boolean InitPCM51xx (u8 ucI2CAddress);
++	void LogWrite (TLogSeverity Severity, const char *pMessage, ...);
++	void DetectDAC ();
++	boolean InitDAC ();
++	template <size_t N> boolean SendAll (const u8 (&initBytes)[N][2]);
+ 
+ private:
+ 	CInterruptSystem *m_pInterruptSystem;
+diff --git a/lib/i2ssoundbasedevice.cpp b/lib/i2ssoundbasedevice.cpp
+index c5df60a1..0825031b 100644
+--- a/lib/i2ssoundbasedevice.cpp
++++ b/lib/i2ssoundbasedevice.cpp
+@@ -164,21 +164,13 @@ boolean CI2SSoundBaseDevice::Start (void)
+ 	    && m_pI2CMaster != 0
+ 	    && !m_bI2CInited)
+ 	{
+-		if (m_ucI2CAddress != 0)
+-		{
+-			if (!InitPCM51xx (m_ucI2CAddress))	// fixed address, must succeed
+-			{
+-				m_bError = TRUE;
++		DetectDAC ();
+ 
+-				return FALSE;
+-			}
+-		}
+-		else
++		if (!InitDAC ())
+ 		{
+-			if (!InitPCM51xx (0x4C))		// auto probing, ignore failure
+-			{
+-				InitPCM51xx (0x4D);
+-			}
++			m_bError = TRUE;
++
++			return FALSE;
+ 		}
+ 
+ 		m_bI2CInited = TRUE;
+@@ -422,17 +414,51 @@ unsigned CI2SSoundBaseDevice::RXCompletedHandler (boolean bStatus, u32 *pBuffer,
+ 	return 0;
+ }
+ 
++void CI2SSoundBaseDevice::LogWrite (TLogSeverity Severity, const char *pMessage, ...)
++{
++	va_list var;
++	va_start (var, pMessage);
++	CLogger::Get ()->WriteV ("CI2SSoundBaseDevice", Severity, pMessage, var);
++	va_end (var);
++}
++
++void CI2SSoundBaseDevice::DetectDAC () {
++	if (m_ucI2CAddress != 0)
++	{
++		return; // No need to guess if address is provided
++	}
++	static const u8 knownAddresses[] = {0x1A, 0x4C, 0x4D};
++	for (auto &address : knownAddresses)
++	{
++		int written = m_pI2CMaster->Write (address, nullptr, 0);
++		LogWrite (LogNotice, "Scan result at i2c address %u: %d", address, written);
++		if (written == 0) {
++			m_ucI2CAddress = address;
++			return;
++		}
++	}
++}
++
++// For WM8960 i2c register is 7 bits and value is 9 bits,
++// so let's have a helper for packing this into two bytes
++#define SHIFT_BIT(r, v) {((v&0x0100)>>8) | (r<<1), (v&0xff)}
++
+ //
+-// Taken from the file mt32pi.cpp from this project:
++// Based on the file mt32pi.cpp from this project:
+ //
+ // mt32-pi - A baremetal MIDI synthesizer for Raspberry Pi
+ // Copyright (C) 2020-2021 Dale Whinham <daleyo@gmail.com>
+ //
+ // Licensed under GPLv3
+ //
+-boolean CI2SSoundBaseDevice::InitPCM51xx (u8 ucI2CAddress)
++boolean CI2SSoundBaseDevice::InitDAC ()
+ {
+-	static const u8 initBytes[][2] =
++	if (m_ucI2CAddress == 0)
++	{
++		return TRUE; // No DAC, no need to init
++	}
++
++	static const u8 initBytesPCM51xx[][2] =
+ 	{
+ 		// Set PLL reference clock to BCK (set SREF to 001b)
+ 		{ 0x0d, 0x10 },
+@@ -444,9 +470,70 @@ boolean CI2SSoundBaseDevice::InitPCM51xx (u8 ucI2CAddress)
+ 		{ 0x41, 0x04 }
+ 	};
+ 
++	// based on https://github.com/RASPIAUDIO/ULTRA/blob/main/ultra.c
++	static const u8 initBytesWM8960[][2] =
++	{
++		// reset
++		SHIFT_BIT(15, 0x000),
++		// Power
++		SHIFT_BIT(25, 0x1FC),
++		SHIFT_BIT(26, 0x1F9),
++		SHIFT_BIT(47, 0x03C),
++		// Clock PLL
++		SHIFT_BIT(4, 0x001),
++		SHIFT_BIT(52, 0x027),
++		SHIFT_BIT(53, 0x086),
++		SHIFT_BIT(54, 0x0C2),
++		SHIFT_BIT(55, 0x026),
++		// ADC/DAC
++		SHIFT_BIT(5, 0x000),
++		SHIFT_BIT(7, 0x002),
++		// ALC and Noise control
++		SHIFT_BIT(20, 0x0F9),
++		SHIFT_BIT(17, 0x1FB),
++		SHIFT_BIT(18, 0x000),
++		SHIFT_BIT(19, 0x032),
++		// OUT1 volume
++		SHIFT_BIT(2, 0x16F),
++		SHIFT_BIT(3, 0x16F),
++		//SPK volume
++		SHIFT_BIT(40, 0x17F),
++		SHIFT_BIT(41, 0x178),
++		SHIFT_BIT(51, 0x08D),
++		// input volume
++		SHIFT_BIT(0, 0x13F),
++		SHIFT_BIT(1, 0x13F),
++		// INPUTS
++		SHIFT_BIT(32, 0x138),
++		SHIFT_BIT(33, 0x138),
++		// OUTPUTS
++		SHIFT_BIT(49, 0x0F7),
++		SHIFT_BIT(10, 0x1FF),
++		SHIFT_BIT(11, 0x1FF),
++		SHIFT_BIT(34, 0x100),
++		SHIFT_BIT(37, 0x100)
++	};
++
++	switch (m_ucI2CAddress)
++	{
++	case 0x4C:
++	case 0x4D:
++		return SendAll(initBytesPCM51xx);
++
++	case 0x1A:
++		return SendAll(initBytesWM8960);
++	
++	default:
++		LogWrite (LogError, "Don't know how to init device at i2c address %u", m_ucI2CAddress);
++		return FALSE;
++	}
++}
++
++template <size_t N> boolean CI2SSoundBaseDevice::SendAll (const u8 (&initBytes)[N][2])
++{
+ 	for (auto &command : initBytes)
+ 	{
+-		if (   m_pI2CMaster->Write (ucI2CAddress, &command, sizeof (command))
++		if (   m_pI2CMaster->Write (m_ucI2CAddress, &command, sizeof (command))
+ 		    != sizeof (command))
+ 		{
+ 			return FALSE;