Add func to get nbr of PMU event counters

Small bugfix to a print in driver

Change-Id: I277a441a9f65c647c338b92af5a908176929102c
diff --git a/include/pmu_ethosu.h b/include/pmu_ethosu.h
index 0c1475d..1a9bfd8 100644
--- a/include/pmu_ethosu.h
+++ b/include/pmu_ethosu.h
@@ -154,6 +154,12 @@
 void ETHOSU_PMU_Set_EVTYPER(struct ethosu_driver *drv, uint32_t num, enum ethosu_pmu_event_type type);
 
 /**
+ * \brief   Get number of PMU event counters
+ * \return                Number of event counters
+ */
+uint32_t ETHOSU_PMU_Get_NumEventCounters(void);
+
+/**
  * \brief   Get event to count for PMU eventer counter
  * \param [in]    num     Event counter (0-ETHOSU_PMU_NCOUNTERS) to configure
  * \return        type    Event to count
diff --git a/src/ethosu_device.h b/src/ethosu_device.h
index 2f41d5c..cc9ea8b 100644
--- a/src/ethosu_device.h
+++ b/src/ethosu_device.h
@@ -35,6 +35,7 @@
  * Defines
  ******************************************************************************/
 
+// NOTE: Deprecated
 #ifndef ETHOSU_PMU_NCOUNTERS
 #define ETHOSU_PMU_NCOUNTERS 4
 #endif
diff --git a/src/ethosu_driver.c b/src/ethosu_driver.c
index 522f3e8..fedb2a1 100644
--- a/src/ethosu_driver.c
+++ b/src/ethosu_driver.c
@@ -285,7 +285,7 @@
         drv = drv->next;
     }
 
-    LOG_DEBUG("No NPU driver handle available.", drv);
+    LOG_WARN("No NPU driver handle available.");
 
     return NULL;
 }
diff --git a/src/ethosu_pmu.c b/src/ethosu_pmu.c
index 647f3b0..e11636a 100644
--- a/src/ethosu_pmu.c
+++ b/src/ethosu_pmu.c
@@ -101,6 +101,11 @@
     set_clock_and_power_request(drv, ETHOSU_PMU_REQUEST, ETHOSU_CLOCK_Q_ENABLE, ETHOSU_POWER_Q_ENABLE);
 }
 
+uint32_t ETHOSU_PMU_Get_NumEventCounters(void)
+{
+    return NPU_REG_PMEVCNTR_ARRLEN;
+}
+
 void ETHOSU_PMU_Set_EVTYPER(struct ethosu_driver *drv, uint32_t num, enum ethosu_pmu_event_type type)
 {
     assert(num < ETHOSU_PMU_NCOUNTERS);