DataFlash: Use battery singleton

libraries/DataFlash/DataFlash.h

@@ -139,7 +139,7 @@ public:
     void Log_Write_Airspeed(AP_Airspeed &airspeed);
     void Log_Write_Attitude(AP_AHRS &ahrs, const Vector3f &targets);
     void Log_Write_AttitudeView(AP_AHRS_View &ahrs, const Vector3f &targets);
-    void Log_Write_Current(const AP_BattMonitor &battery);
+    void Log_Write_Current();
     void Log_Write_Compass(const Compass &compass, uint64_t time_us=0);
     void Log_Write_Mode(uint8_t mode, uint8_t reason = 0);
 
@@ -304,8 +304,7 @@ private:
                                     uint64_t time_us,
                                     uint8_t mag_instance,
                                     enum LogMessages type);
-    void Log_Write_Current_instance(const AP_BattMonitor &battery,
-                                    uint64_t time_us,
+    void Log_Write_Current_instance(uint64_t time_us,
                                     uint8_t battery_instance,
                                     enum LogMessages type,
                                     enum LogMessages celltype);

libraries/DataFlash/LogFile.cpp

@@ -1547,12 +1547,12 @@ void DataFlash_Class::Log_Write_AttitudeView(AP_AHRS_View &ahrs, const Vector3f
     WriteBlock(&pkt, sizeof(pkt));
 }
 
-void DataFlash_Class::Log_Write_Current_instance(const AP_BattMonitor &battery,
-                                                 const uint64_t time_us,
+void DataFlash_Class::Log_Write_Current_instance(const uint64_t time_us,
                                                  const uint8_t battery_instance,
                                                  const enum LogMessages type,
                                                  const enum LogMessages celltype)
 {
+    AP_BattMonitor &battery = AP::battery();
     float temp;
     bool has_temp = battery.get_temperature(temp, battery_instance);
     struct log_Current pkt = {
@@ -1587,20 +1587,19 @@ void DataFlash_Class::Log_Write_Current_instance(const AP_BattMonitor &battery,
 }
 
 // Write an Current data packet
-void DataFlash_Class::Log_Write_Current(const AP_BattMonitor &battery)
+void DataFlash_Class::Log_Write_Current()
 {
     const uint64_t time_us = AP_HAL::micros64();
-    if (battery.num_instances() >= 1) {
-        Log_Write_Current_instance(battery,
-                                   time_us,
+    const uint8_t num_instances = AP::battery().num_instances();
+    if (num_instances >= 1) {
+        Log_Write_Current_instance(time_us,
                                    0,
                                    LOG_CURRENT_MSG,
                                    LOG_CURRENT_CELLS_MSG);
     }
 
-    if (battery.num_instances() >= 2) {
-        Log_Write_Current_instance(battery,
-                                   time_us,
+    if (num_instances >= 2) {
+        Log_Write_Current_instance(time_us,
                                    1,
                                    LOG_CURRENT2_MSG,
                                    LOG_CURRENT_CELLS2_MSG);