board: aplhax-silver: read board revsion from PCA9555

firmware/config/boards/hellen/alphax-silver/board_configuration.cpp

@@ -1,10 +1,13 @@
 #include "pch.h"
 #include "hellen_meta.h"
+#include "i2c_bb.h"
 #include "defaults.h"
 #include "hellen_leds_100.cpp"
 #include "smart_gpio.h"
 #include "drivers/gpio/tle9104.h"
 
+#define PCA9555_I2C_ADDR	0x20
+
 static OutputPin alphaTempPullUp;
 
 static void setInjectorPins() {
@@ -35,6 +38,44 @@ static void setupDefaultSensorInputs() {
 	engineConfiguration->iat.adcChannel = MM100_IN_IAT_ANALOG;
 }
 
+
+static uint32_t getBoardRevision() {
+	static bool isFirstInvocation = true;
+	static uint32_t variant;
+
+	if (isFirstInvocation) {
+		BitbangI2c m_i2c;
+		const uint8_t set_out[3] = {0x06, 0xff, 0xff};
+		const uint8_t read_inputs_cmd[1] = {0x00};
+		uint8_t rx[2] = {0xff, 0xff};
+
+		//same pins as for LPS25
+		m_i2c.init(Gpio::B10, Gpio::B11);
+
+		// configuration registers:
+		// after reset all IO pins should be configured as output, so ttis step can be skipped
+		m_i2c.write(PCA9555_I2C_ADDR, set_out, sizeof(set_out));
+
+		// read registers 0 and 1: Input port registers
+		m_i2c.writeRead(PCA9555_I2C_ADDR, read_inputs_cmd, sizeof(read_inputs_cmd), rx, sizeof(rx));
+
+		variant = (rx[1] << 8) | (rx[0] << 0);
+
+		efiPrintf("Board variant 0x%04x\n", (unsigned int)variant);
+
+		isFirstInvocation = false;
+
+		// release gpios for LPS25 driver
+		m_i2c.deinit();
+	}
+
+	return variant;
+}
+
+int hackHellenBoardId(int /* detectedId */) {
+	return getBoardRevision();
+}
+
 void setBoardConfigOverrides() {
 	/* Force PWR_EN as TLE9104s are powered from +5VA */
 	setHellenMegaEnPin();