AP_Notify: Display backend methods become void

We never use the return value so might as well remove it

libraries/AP_Notify/Display_Backend.h

@@ -13,8 +13,8 @@ class Display_Backend {
 
 public:
     virtual bool hw_init() = 0;
-    virtual bool hw_update() = 0;
-    virtual bool set_pixel(uint16_t x, uint16_t y) = 0;
-    virtual bool clear_pixel(uint16_t x, uint16_t y) = 0;
-    virtual bool clear_screen() = 0;
+    virtual void hw_update() = 0;
+    virtual void set_pixel(uint16_t x, uint16_t y) = 0;
+    virtual void clear_pixel(uint16_t x, uint16_t y) = 0;
+    virtual void clear_screen() = 0;
 };

libraries/AP_Notify/Display_SH1106_I2C.cpp

@@ -71,10 +71,9 @@ bool Display_SH1106_I2C::hw_init()
     return success;
 }
 
-bool Display_SH1106_I2C::hw_update()
+void Display_SH1106_I2C::hw_update()
 {
     _need_hw_update = true;
-    return true;
 }
 
 void Display_SH1106_I2C::_timer()
@@ -109,31 +108,29 @@ void Display_SH1106_I2C::_timer()
     }
 }
 
-bool Display_SH1106_I2C::set_pixel(uint16_t x, uint16_t y)
+void Display_SH1106_I2C::set_pixel(uint16_t x, uint16_t y)
 {
     // check x, y range
     if ((x >= SH1106_COLUMNS) || (y >= SH1106_ROWS)) {
-        return false;
+        return;
     }
     // set pixel in buffer
     _displaybuffer[x + (y / 8 * SH1106_COLUMNS)] |= 1 << (y % 8);
 
-    return true;
 }
 
-bool Display_SH1106_I2C::clear_pixel(uint16_t x, uint16_t y)
+void Display_SH1106_I2C::clear_pixel(uint16_t x, uint16_t y)
 {
     // check x, y range
     if ((x >= SH1106_COLUMNS) || (y >= SH1106_ROWS)) {
-        return false;
+        return;
     }
     // clear pixel in buffer
     _displaybuffer[x + (y / 8 * SH1106_COLUMNS)] &= ~(1 << (y % 8));
 
-    return true;
 }
-bool Display_SH1106_I2C::clear_screen()
+void Display_SH1106_I2C::clear_screen()
 {
      memset(_displaybuffer, 0, SH1106_COLUMNS * SH1106_ROWS_PER_PAGE);
-     return true;
+        return;
 }

libraries/AP_Notify/Display_SH1106_I2C.h

@@ -14,10 +14,10 @@ public:
     Display_SH1106_I2C(AP_HAL::OwnPtr<AP_HAL::Device> dev);
 
     bool hw_init() override;
-    bool hw_update() override;
-    bool set_pixel(uint16_t x, uint16_t y) override;
-    bool clear_pixel(uint16_t x, uint16_t y) override;
-    bool clear_screen() override;
+    void hw_update() override;
+    void set_pixel(uint16_t x, uint16_t y) override;
+    void clear_pixel(uint16_t x, uint16_t y) override;
+    void clear_screen() override;
 
 private:
     void _timer();

libraries/AP_Notify/Display_SSD1306_I2C.cpp

@@ -79,10 +79,9 @@ bool Display_SSD1306_I2C::hw_init()
     return success;
 }
 
-bool Display_SSD1306_I2C::hw_update()
+void Display_SSD1306_I2C::hw_update()
 {
     _need_hw_update = true;
-    return true;
 }
 
 void Display_SSD1306_I2C::_timer()
@@ -115,31 +114,28 @@ void Display_SSD1306_I2C::_timer()
     }
 }
 
-bool Display_SSD1306_I2C::set_pixel(uint16_t x, uint16_t y)
+void Display_SSD1306_I2C::set_pixel(uint16_t x, uint16_t y)
 {
     // check x, y range
     if ((x >= SSD1306_COLUMNS) || (y >= SSD1306_ROWS)) {
-        return false;
+        return;
     }
     // set pixel in buffer
     _displaybuffer[x + (y / 8 * SSD1306_COLUMNS)] |= 1 << (y % 8);
 
-    return true;
 }
 
-bool Display_SSD1306_I2C::clear_pixel(uint16_t x, uint16_t y)
+void Display_SSD1306_I2C::clear_pixel(uint16_t x, uint16_t y)
 {
     // check x, y range
     if ((x >= SSD1306_COLUMNS) || (y >= SSD1306_ROWS)) {
-        return false;
+        return;
     }
     // clear pixel in buffer
     _displaybuffer[x + (y / 8 * SSD1306_COLUMNS)] &= ~(1 << (y % 8));
 
-    return true;
 }
-bool Display_SSD1306_I2C::clear_screen()
+void Display_SSD1306_I2C::clear_screen()
 {
      memset(_displaybuffer, 0, SSD1306_COLUMNS * SSD1306_ROWS_PER_PAGE);
-     return true;
 }

libraries/AP_Notify/Display_SSD1306_I2C.h

@@ -14,10 +14,10 @@ public:
     Display_SSD1306_I2C(AP_HAL::OwnPtr<AP_HAL::Device> dev);
 
     bool hw_init() override;
-    bool hw_update() override;
-    bool set_pixel(uint16_t x, uint16_t y) override;
-    bool clear_pixel(uint16_t x, uint16_t y) override;
-    bool clear_screen() override;
+    void hw_update() override;
+    void set_pixel(uint16_t x, uint16_t y) override;
+    void clear_pixel(uint16_t x, uint16_t y) override;
+    void clear_screen() override;
 
 private:
     void _timer();