TM: Store only the last autotune result state

- Remove tm::valid and temp_model_valid as it's a duplicate of the
  calibrated() state.
- Add temp_model_autotune_result() for future use.

Firmware/temp_model.h

@@ -60,7 +60,6 @@ struct model_data
 };
 
 static bool enabled;          // model check enabled
-static bool valid = false;    // model is valid
 static bool warn_beep = true; // beep on warning threshold
 static model_data data;       // default heater data
 

Firmware/temperature.cpp

@@ -2506,7 +2506,6 @@ static void temp_model_reset_enabled(bool enabled)
 {
     TempMgrGuard temp_mgr_guard;
     temp_model::enabled = enabled;
-    temp_model::valid = enabled;
     temp_model::data.flag_bits.uninitialized = true;
 }
 
@@ -2517,19 +2516,11 @@ void temp_model_set_enabled(bool enabled)
         TempMgrGuard temp_mgr_guard;
         temp_model::enabled = enabled;
         temp_model::setup();
-        temp_model::valid = true;
     }
 
     // verify that the model has been enabled
-    if(enabled && !temp_model::enabled) {
+    if(enabled && !temp_model::enabled)
         SERIAL_ECHOLNPGM("TM: invalid parameters, cannot enable");
-        temp_model::valid = false;
-    }
-}
-
-bool temp_model_valid()
-{
-  return temp_model::valid;
 }
 
 void temp_model_set_warn_beep(bool enabled)
@@ -2590,7 +2581,6 @@ void temp_model_reset_settings()
     temp_model::data.err = TEMP_MODEL_E;
     temp_model::warn_beep = true;
     temp_model::enabled = true;
-    temp_model::valid = false;
 }
 
 void temp_model_load_settings()
@@ -2888,8 +2878,12 @@ static bool autotune(int16_t cal_temp)
 
 } // namespace temp_model_cal
 
+static bool temp_model_autotune_err = true;
+
 void temp_model_autotune(int16_t temp, bool selftest)
 {
+    temp_model_autotune_err = true;
+
     char tm_message[LCD_WIDTH+1];
     if(moves_planned() || printer_active()) {
         sprintf_P(tm_message, PSTR("TM: Cal. NOT IDLE"));
@@ -2907,12 +2901,12 @@ void temp_model_autotune(int16_t temp, bool selftest)
     temp_model_reset_enabled(selftest);
 
     SERIAL_ECHOLNPGM("TM: calibration start");
-    bool err = temp_model_cal::autotune(temp > 0 ? temp : TEMP_MODEL_CAL_Th);
+    temp_model_autotune_err = temp_model_cal::autotune(temp > 0 ? temp : TEMP_MODEL_CAL_Th);
 
     // always reset temperature
     disable_heater();
 
-    if(err) {
+    if(temp_model_autotune_err) {
         sprintf_P(tm_message, PSTR("TM: calibr. failed!"));
         lcd_setstatus_serial(tm_message);
         if(temp_error_state.v)
@@ -2928,6 +2922,11 @@ void temp_model_autotune(int16_t temp, bool selftest)
     menu_unset_block(MENU_BLOCK_TEMP_MODEL_AUTOTUNE);
 }
 
+bool temp_model_autotune_result()
+{
+    return !temp_model_autotune_err;
+}
+
 #ifdef TEMP_MODEL_DEBUG
 void temp_model_log_enable(bool enable)
 {

Firmware/temperature.h

@@ -218,7 +218,6 @@ void PID_autotune(float temp, int extruder, int ncycles);
 
 #ifdef TEMP_MODEL
 void temp_model_set_enabled(bool enabled);
-bool temp_model_valid();
 void temp_model_set_warn_beep(bool enabled);
 void temp_model_set_params(float C = NAN, float P = NAN, float Ta_corr = NAN, float warn = NAN, float err = NAN);
 void temp_model_set_resistance(uint8_t index, float R);
@@ -229,6 +228,7 @@ void temp_model_load_settings();
 void temp_model_save_settings();
 
 void temp_model_autotune(int16_t temp = 0, bool selftest = false);
+bool temp_model_autotune_result(); // return true if the last autotune was complete and successful
 
 #ifdef TEMP_MODEL_DEBUG
 void temp_model_log_enable(bool enable);