From 7aea21bd4029d258b8ff4baa1bdf8d1dcaf04bb3 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Sat, 2 Sep 2023 20:36:40 +1000
Subject: [PATCH] AP_BattMonitor: log external temperature if available

---
 libraries/AP_BattMonitor/AP_BattMonitor.cpp        | 11 +----------
 .../AP_BattMonitor/AP_BattMonitor_Backend.cpp      | 14 ++++++++++++++
 libraries/AP_BattMonitor/AP_BattMonitor_Backend.h  |  3 +++
 .../AP_BattMonitor/AP_BattMonitor_Logging.cpp      |  8 +++++++-
 4 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/libraries/AP_BattMonitor/AP_BattMonitor.cpp b/libraries/AP_BattMonitor/AP_BattMonitor.cpp
index 0c0dc8b314..b53fb55465 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor.cpp
@@ -879,18 +879,9 @@ bool AP_BattMonitor::get_temperature(float &temperature, const uint8_t instance)
 {
     if (instance >= _num_instances || drivers[instance] == nullptr) {
         return false;
-    } 
-    
-#if AP_TEMPERATURE_SENSOR_ENABLED
-    if (state[instance].temperature_external_use) {
-        temperature = state[instance].temperature_external;
-        return true;
     }
-#endif
 
-    temperature = state[instance].temperature;
-
-    return drivers[instance]->has_temperature();
+    return drivers[instance]->get_temperature(temperature);
 }
 
 #if AP_TEMPERATURE_SENSOR_ENABLED
diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_Backend.cpp b/libraries/AP_BattMonitor/AP_BattMonitor_Backend.cpp
index 729d5d0247..c137aa2c14 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_Backend.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_Backend.cpp
@@ -272,6 +272,20 @@ void AP_BattMonitor_Backend::update_esc_telem_outbound()
 }
 #endif
 
+// returns true if battery monitor provides temperature
+bool AP_BattMonitor_Backend::get_temperature(float &temperature) const
+{
+#if AP_TEMPERATURE_SENSOR_ENABLED
+    if (_state.temperature_external_use) {
+        temperature = _state.temperature_external;
+        return true;
+    }
+#endif
+
+    temperature = _state.temperature;
+
+    return has_temperature();
+}
 
 /*
   default implementation for reset_remaining(). This sets consumed_wh
diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_Backend.h b/libraries/AP_BattMonitor/AP_BattMonitor_Backend.h
index 84ec427fe8..85d6212770 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_Backend.h
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_Backend.h
@@ -48,6 +48,9 @@ public:
     // returns true if battery monitor provides temperature
     virtual bool has_temperature() const { return false; }
 
+    // returns true if temperature retrieved successfully
+    virtual bool get_temperature(float &temperature) const;
+
     // capacity_remaining_pct - returns true if the battery % is available and writes to the percentage argument
     // returns false if the battery is unhealthy, does not have current monitoring, or the pack_capacity is too small
     virtual bool capacity_remaining_pct(uint8_t &percentage) const WARN_IF_UNUSED;
diff --git a/libraries/AP_BattMonitor/AP_BattMonitor_Logging.cpp b/libraries/AP_BattMonitor/AP_BattMonitor_Logging.cpp
index bb32de92f7..f5595d321a 100644
--- a/libraries/AP_BattMonitor/AP_BattMonitor_Logging.cpp
+++ b/libraries/AP_BattMonitor/AP_BattMonitor_Logging.cpp
@@ -10,6 +10,12 @@ void AP_BattMonitor_Backend::Log_Write_BAT(const uint8_t instance, const uint64_
     uint8_t percent = -1;
     IGNORE_RETURN(capacity_remaining_pct(percent));
 
+    float temperature;
+    int16_t temperature_cd = 0;
+    if (get_temperature(temperature)) {
+        temperature_cd = temperature * 100.0;
+    }
+
     const struct log_BAT pkt{
         LOG_PACKET_HEADER_INIT(LOG_BAT_MSG),
         time_us             : time_us,
@@ -19,7 +25,7 @@ void AP_BattMonitor_Backend::Log_Write_BAT(const uint8_t instance, const uint64_
         current_amps        : has_curr ? _state.current_amps : AP::logger().quiet_nanf(),
         current_total       : has_curr ? _state.consumed_mah : AP::logger().quiet_nanf(),
         consumed_wh         : has_curr ? _state.consumed_wh : AP::logger().quiet_nanf(),
-        temperature         : (int16_t) ( has_temperature() ? _state.temperature * 100 : 0),
+        temperature         : temperature_cd,
         resistance          : _state.resistance,
         rem_percent         : percent,
         health              : _state.healthy