Suppress some compiler warnings

Marlin/Marlin.h

@@ -5,6 +5,10 @@
 #define MARLIN_H
 
 #define  FORCE_INLINE __attribute__((always_inline)) inline
+/**
+ * Compiler warning on unused varable.
+ */
+#define UNUSED(x) (void) (x)
 
 #include <math.h>
 #include <stdio.h>

Marlin/buzzer.cpp

@@ -1,8 +1,8 @@
 #include "Marlin.h"
-#include "buzzer.h"
-#include "ultralcd.h"
-
 #if HAS_BUZZER
+  #include "buzzer.h"
+  #include "ultralcd.h"
+
   void buzz(long duration, uint16_t freq) {
     if (freq > 0) {
       #if ENABLED(LCD_USE_I2C_BUZZER)

Marlin/configuration_store.cpp

@@ -168,7 +168,7 @@ void Config_StoreSettings()  {
     EEPROM_WRITE_VAR(i, mesh_num_x);
     EEPROM_WRITE_VAR(i, mesh_num_y);
     dummy = 0.0f;
-    for (int q=0; q<mesh_num_x*mesh_num_y; q++) EEPROM_WRITE_VAR(i, dummy);
+    for (uint q=0; q<mesh_num_x*mesh_num_y; q++) EEPROM_WRITE_VAR(i, dummy);
   #endif // MESH_BED_LEVELING
 
   #if DISABLED(ENABLE_AUTO_BED_LEVELING)
@@ -470,7 +470,7 @@ void Config_ResetDefault() {
   float tmp1[] = DEFAULT_AXIS_STEPS_PER_UNIT;
   float tmp2[] = DEFAULT_MAX_FEEDRATE;
   long tmp3[] = DEFAULT_MAX_ACCELERATION;
-  for (uint16_t i = 0; i < NUM_AXIS; i++) {
+  for (uint8_t i = 0; i < NUM_AXIS; i++) {
     axis_steps_per_unit[i] = tmp1[i];
     max_feedrate[i] = tmp2[i];
     max_acceleration_units_per_sq_second[i] = tmp3[i];
@@ -565,7 +565,7 @@ void Config_ResetDefault() {
   #endif
 
   volumetric_enabled = false;
-  for (int q=0; q<COUNT(filament_size); q++)
+  for (uint8_t q=0; q<COUNT(filament_size); q++)
     filament_size[q] = DEFAULT_NOMINAL_FILAMENT_DIA;
   calculate_volumetric_multipliers();
 

Marlin/planner.cpp

@@ -217,6 +217,7 @@ FORCE_INLINE float max_allowable_speed(float acceleration, float target_velocity
 // The kernel called by planner_recalculate() when scanning the plan from last to first entry.
 void planner_reverse_pass_kernel(block_t *previous, block_t *current, block_t *next) {
   if (!current) return;
+  UNUSED(previous);
 
   if (next) {
     // If entry speed is already at the maximum entry speed, no need to recheck. Block is cruising.
@@ -265,6 +266,7 @@ void planner_reverse_pass() {
 // The kernel called by planner_recalculate() when scanning the plan from first to last entry.
 void planner_forward_pass_kernel(block_t *previous, block_t *current, block_t *next) {
   if (!previous) return;
+  UNUSED(next);
 
   // If the previous block is an acceleration block, but it is not long enough to complete the
   // full speed change within the block, we need to adjust the entry speed accordingly. Entry

Marlin/stepper.cpp

@@ -1185,6 +1185,9 @@ void digitalPotWrite(int address, int value) {
     SPI.transfer(value);
     digitalWrite(DIGIPOTSS_PIN,HIGH); // take the SS pin high to de-select the chip:
     //delay(10);
+  #else
+    UNUSED(address);
+    UNUSED(value);
   #endif
 }
 
@@ -1216,14 +1219,16 @@ void digipot_current(uint8_t driver, int current) {
   #if HAS_DIGIPOTSS
     const uint8_t digipot_ch[] = DIGIPOT_CHANNELS;
     digitalPotWrite(digipot_ch[driver], current);
-  #endif
-  #ifdef MOTOR_CURRENT_PWM_XY_PIN
+  #elif defined(MOTOR_CURRENT_PWM_XY_PIN)
     switch(driver) {
       case 0: analogWrite(MOTOR_CURRENT_PWM_XY_PIN, 255L * current / MOTOR_CURRENT_PWM_RANGE); break;
       case 1: analogWrite(MOTOR_CURRENT_PWM_Z_PIN, 255L * current / MOTOR_CURRENT_PWM_RANGE); break;
       case 2: analogWrite(MOTOR_CURRENT_PWM_E_PIN, 255L * current / MOTOR_CURRENT_PWM_RANGE); break;
     }
-  #endif
+  #else
+    UNUSED(driver);
+    UNUSED(current);
+#endif
 }
 
 void microstep_init() {

Marlin/ultralcd.h

@@ -2,9 +2,9 @@
 #define ULTRALCD_H
 
 #include "Marlin.h"
-#include "buzzer.h"
-
 #if ENABLED(ULTRA_LCD)
+  #include "buzzer.h"
+
   int lcd_strlen(char *s);
   int lcd_strlen_P(const char *s);
   void lcd_update();
@@ -105,8 +105,8 @@
   FORCE_INLINE void lcd_update() {}
   FORCE_INLINE void lcd_init() {}
   FORCE_INLINE bool lcd_hasstatus() { return false; }
-  FORCE_INLINE void lcd_setstatus(const char* message, const bool persist=false) {}
-  FORCE_INLINE void lcd_setstatuspgm(const char* message, const uint8_t level=0) {}
+  FORCE_INLINE void lcd_setstatus(const char* message, const bool persist=false) {UNUSED(message); UNUSED(persist);}
+  FORCE_INLINE void lcd_setstatuspgm(const char* message, const uint8_t level=0) {UNUSED(message); UNUSED(level);}
   FORCE_INLINE void lcd_buttons_update() {}
   FORCE_INLINE void lcd_reset_alert_level() {}
   FORCE_INLINE bool lcd_detected(void) { return true; }