not all listeners are sensors (#2514)

Co-authored-by: Matthew Kennedy <makenne@microsoft.com>

firmware/controllers/can/can.h

@@ -17,12 +17,14 @@
 #define CAN_TIMEOUT MS2NT(100)
 
 class Logging;
+class CanListener;
 class CanSensorBase;
 
 #if EFI_CAN_SUPPORT
 void processCanRxMessage(const CANRxFrame& msg, Logging* logger, efitick_t nowNt);
 #endif // EFI_CAN_SUPPORT
 
+void registerCanListener(CanListener& listener);
 void registerCanSensor(CanSensorBase& sensor);
 
 // Indicate that an ack response was received from the wideband bootloader

firmware/controllers/can/can_listener.h

@@ -0,0 +1,45 @@
+/**
+ * @file	can_listener.h
+ *
+ * @date March 31, 2021
+ * @author Matthew Kennedy, (c) 2021
+ */
+
+#pragma once
+
+#include "can.h"
+
+class CanListener {
+public:
+	CanListener(uint32_t eid)
+		: m_eid(eid)
+	{
+	}
+
+	CanListener* processFrame(const CANRxFrame& frame, efitick_t nowNt) {
+		if (CAN_EID(frame) == m_eid) {
+			decodeFrame(frame, nowNt);
+		}
+
+		return m_next;
+	}
+
+	uint32_t getEid() {
+		return m_eid;
+	}
+
+	void setNext(CanListener* next) {
+		m_next = next;
+	}
+
+	virtual CanListener* request() {
+		return m_next;
+	}
+
+protected:
+	virtual void decodeFrame(const CANRxFrame& frame, efitick_t nowNt) = 0;
+	CanListener* m_next = nullptr;
+
+private:
+	const uint32_t m_eid;
+};

firmware/controllers/can/can_rx.cpp

@@ -80,19 +80,23 @@ static void printPacket(const CANRxFrame &rx, Logging *logger) {
 
 volatile float canMap = 0;
 
-CanSensorBase *cansensors_head = nullptr;
+CanListener *canListeners_head = nullptr;
 
 void serviceCanSubscribers(const CANRxFrame &frame, efitick_t nowNt) {
-	CanSensorBase *current = cansensors_head;
+	CanListener *current = canListeners_head;
 
 	while (current) {
 		current = current->processFrame(frame, nowNt);
 	}
 }
 
+void registerCanListener(CanListener& listener) {
+	listener.setNext(canListeners_head);
+	canListeners_head = &listener;
+}
+
 void registerCanSensor(CanSensorBase& sensor) {
-	sensor.setNext(cansensors_head);
+	registerCanListener(sensor);
-	cansensors_head = &sensor;
 	sensor.Register();
 }
 

firmware/controllers/can/can_tx.cpp

@@ -20,7 +20,7 @@
 
 EXTERN_ENGINE;
 
-extern CanSensorBase* cansensors_head;
+extern CanListener* canListeners_head;
 
 CanWrite::CanWrite()
 	: PeriodicController("CAN TX", PRIO_CAN_TX, 50)
@@ -35,7 +35,7 @@ void CanWrite::PeriodicTask(efitime_t nowNt) {
 		sendCanVerbose();
 	}
 
-	CanSensorBase* current = cansensors_head;
+	CanListener* current = canListeners_head;
 
 	while (current) {
 		current = current->request();

firmware/controllers/sensors/can_sensor.h

@@ -13,46 +13,20 @@
 #include "can_msg_tx.h"
 #include "obd2.h"
 #include "can.h"
+#include "can_listener.h"
 
 /**
  * Sensor which reads it's value from CAN
  */
-class CanSensorBase : public StoredValueSensor {
+class CanSensorBase : public StoredValueSensor, public CanListener {
 public:
 	CanSensorBase(uint32_t eid, SensorType type, efitick_t timeout)
 		: StoredValueSensor(type, timeout)
-		, m_eid(eid)
+		, CanListener(eid)
 	{
 	}
 
-	virtual CanSensorBase* request() {
-		return m_next;
-	}
-
 	void showInfo(Logging* logger, const char* sensorName) const override;
-
-	CanSensorBase* processFrame(const CANRxFrame& frame, efitick_t nowNt) {
-		if (CAN_EID(frame) == m_eid) {
-			decodeFrame(frame, nowNt);
-		}
-
-		return m_next;
-	}
-
-	uint32_t getEid() {
-		return m_eid;
-	}
-
-	void setNext(CanSensorBase* next) {
-		m_next = next;
-	}
-
-protected:
-	virtual void decodeFrame(const CANRxFrame& frame, efitick_t nowNt) = 0;
-	CanSensorBase* m_next = nullptr;
-
-private:
-	const uint32_t m_eid;
 };
 
 template <typename TStorage, int TScale>
@@ -105,7 +79,7 @@ public:
 		setValidValue(fValue, nowNt);
 	}
 
-	CanSensorBase* request() override {
+	CanListener* request() override {
 		{
 			CanTxMessage msg(OBD_TEST_REQUEST);
 			msg[0] = _OBD_2;
@@ -115,7 +89,7 @@ public:
 		// let's sleep on write update after each OBD request, this would give read thread a chance to read response
 		// todo: smarter logic of all this with with semaphore not just sleep
 		chThdSleepMilliseconds(300);
-		return m_next;
+		return CanListener::request();
 	}
 
 	int PID;