drivers/foc: support for BEMF sensing

drivers/motor/foc/Kconfig

@@ -22,6 +22,10 @@ config MOTOR_FOC_SHUNTS
 		Number of shunts supported (or other types of current sensors).
 		Any current reconstruction must be done on the lower-half side.
 
+config MOTOR_FOC_BEMF_SENSE
+	bool "FOC support for Back-EMF sensing"
+	default n
+
 config MOTOR_FOC_TRACE
 	bool "FOC trace support"
 	default n

drivers/motor/foc/foc_dev.c

@@ -62,7 +62,8 @@ static int foc_info_get(FAR struct foc_dev_s *dev,
                         FAR struct foc_info_s *info);
 
 static int foc_notifier(FAR struct foc_dev_s *dev,
-                        FAR foc_current_t *current);
+                        FAR foc_current_t *current,
+                        FAR foc_voltage_t *voltage);
 
 /****************************************************************************
  * Private Data
@@ -726,7 +727,8 @@ static int foc_info_get(FAR struct foc_dev_s *dev,
  ****************************************************************************/
 
 static int foc_notifier(FAR struct foc_dev_s *dev,
-                        FAR foc_current_t *current)
+                        FAR foc_current_t *current,
+                        FAR foc_voltage_t *voltage)
 {
   int ret  = OK;
   int sval = 0;
@@ -743,6 +745,18 @@ static int foc_notifier(FAR struct foc_dev_s *dev,
          current,
          sizeof(foc_current_t) * CONFIG_MOTOR_FOC_PHASES);
 
+#ifdef CONFIG_MOTOR_FOC_BEMF_SENSE
+  /* Copy voltage */
+
+  memcpy(&dev->state.volt,
+         voltage,
+         sizeof(foc_voltage_t) * CONFIG_MOTOR_FOC_PHASES);
+#else
+  /* If BEMF sampling is not enabled then voltage must be NULL */
+
+  DEBUGASSERT(voltage == NULL);
+#endif
+
   /* Check if the previous cycle was handled */
 
   ret = nxsem_get_value(&dev->statesem, &sval);

drivers/motor/foc/foc_dummy.c

@@ -79,6 +79,12 @@ struct foc_dummy_data_s
 
   foc_current_t current[CONFIG_MOTOR_FOC_PHASES];
 
+#ifdef CONFIG_MOTOR_FOC_BEMF_SENSE
+  /* BEMF voltage */
+
+  foc_voltage_t volt[CONFIG_MOTOR_FOC_PHASES];
+#endif
+
   /* FOC worker loop helpers */
 
   bool     state;
@@ -464,7 +470,11 @@ static void foc_dummy_notifier_handler(FAR struct foc_dev_s *dev)
     {
       /* Call FOC notifier */
 
-      sim->cb->notifier(dev, sim->current);
+#ifdef CONFIG_MOTOR_FOC_BEMF_SENSE
+      sim->cb->notifier(dev, sim->current, sim->voltage);
+#else
+      sim->cb->notifier(dev, sim->current, NULL);
+#endif
     }
 
   /* Increase counter */