Inital support for I2C bus scanning

- needs to be configurable
- needs to NOT trash the i2c bus when finished

src/main.cpp

@@ -1126,6 +1126,31 @@ void DisplayOptions(int y_pos)
 	screen.PrintText(false, 0, y_pos += 16, tempBuffer, COLOUR_WHITE, COLOUR_BLACK);
 }
 
+void DisplayI2CScan(int y_pos)
+{
+	int BSCMaster = options.I2CBusMaster();
+
+	snprintf(tempBuffer, tempBufferSize, "Scanning i2c devices on bus %d ...\r\n", BSCMaster);
+	screen.PrintText(false, 0, y_pos += 16, tempBuffer, COLOUR_WHITE, COLOUR_BLACK);
+	RPI_I2CInit(BSCMaster, 1);
+	int address = 0;
+	for (int y=0; y<8; y++)
+	{
+		int x=0;
+		for (x=0; x<16; x++)
+		{
+			int ret = RPI_I2CScan(BSCMaster, address);
+			if (ret)
+				tempBuffer[x] = '*';
+			else
+				tempBuffer[x] = '.';
+			address++;
+		}
+		tempBuffer[x] = 0;
+		screen.PrintText(false, 0, y_pos += 16, tempBuffer, COLOUR_WHITE, COLOUR_BLACK);
+	}
+}
+
 static void CheckOptions()
 {
 	FIL fp;
@@ -1255,6 +1280,9 @@ extern "C"
 		if (options.ShowOptions())
 			DisplayOptions(y_pos+32);
 
+//		if (options.I2CScan())
+			DisplayI2CScan(y_pos+32);
+
 		if (!options.QuickBoot())
 			IEC_Bus::WaitMicroSeconds(3 * 1000000);
 

src/rpi-i2c.c

@@ -184,3 +184,32 @@ int RPI_I2CWrite(int BSCMaster, unsigned char slaveAddress, void* buffer, unsign
 	//DEBUG_LOG("I2C Write %d %d\r\n", count, success);
 	return success;
 }
+
+int RPI_I2CScan(int BSCMaster, unsigned char slaveAddress)
+{
+	int success = 1;
+	if (slaveAddress < 0x80)
+	{
+		unsigned baseAddress = GetBaseAddress(BSCMaster);
+
+		write32(baseAddress + I2C_BSC_A, slaveAddress);
+		write32(baseAddress + I2C_BSC_C, CONTROL_BIT_CLEAR1);
+		write32(baseAddress + I2C_BSC_S, STATUS_BIT_CLKT | STATUS_BIT_ERR | STATUS_BIT_DONE);
+		write32(baseAddress + I2C_BSC_DLEN, 1);
+		write32(baseAddress + I2C_BSC_C, CONTROL_BIT_I2CEN | CONTROL_BIT_ST | CONTROL_BIT_READ);
+
+		while (!(read32(baseAddress + I2C_BSC_S) & STATUS_BIT_DONE))
+		{
+		}
+
+		unsigned status = read32(baseAddress + I2C_BSC_S);
+		if (status & (STATUS_BIT_ERR | STATUS_BIT_CLKT) )
+		{
+			success = 0;
+		}
+
+		write32(baseAddress + I2C_BSC_S, STATUS_BIT_CLKT | STATUS_BIT_ERR | STATUS_BIT_DONE);
+	}
+	return success;
+}
+

src/rpi-i2c.h

@@ -1,5 +1,5 @@
-#ifndef RPI_AUX_H
+#ifndef RPI_I2C_H
-#define RPI_AUX_H
+#define RPI_I2C_H
 
 #include "rpi-base.h"
 
@@ -7,5 +7,6 @@ extern void RPI_I2CInit(int BSCMaster, int fast);
 extern void RPI_I2CSetClock(int BSCMaster, int clock_freq);
 extern int RPI_I2CRead(int BSCMaster, unsigned char slaveAddress, void* buffer, unsigned count);
 extern int RPI_I2CWrite(int BSCMaster, unsigned char slaveAddress, void* buffer, unsigned count);
+extern int RPI_I2CScan(int BSCMaster, unsigned char slaveAddress);
 
 #endif