M256 LCD brightness (#22478)

Marlin/src/gcode/gcode.cpp

         case 250: M250(); break;                                  // M250: Set LCD contrast
       #endif
 
+      #if HAS_LCD_BRIGHTNESS
+        case 256: M256(); break;                                  // M256: Set LCD brightness
+      #endif
+
       #if ENABLED(EXPERIMENTAL_I2CBUS)
         case 260: M260(); break;                                  // M260: Send data to an i2c slave
         case 261: M261(); break;                                  // M261: Request data from an i2c slave

Marlin/src/gcode/gcode.h

  * M226 - Wait until a pin is in a given state: "M226 P<pin> S<state>" (Requires DIRECT_PIN_CONTROL)
  * M240 - Trigger a camera to take a photograph. (Requires PHOTO_GCODE)
  * M250 - Set LCD contrast: "M250 C<contrast>" (0-63). (Requires LCD support)
+ * M256 - Set LCD brightness: "M256 B<brightness>" (0-255). (Requires an LCD with brightness control)
  * M260 - i2c Send Data (Requires EXPERIMENTAL_I2CBUS)
  * M261 - i2c Request Data (Requires EXPERIMENTAL_I2CBUS)
  * M280 - Set servo position absolute: "M280 P<index> S<angle|µs>". (Requires servos)
     static void M250();
   #endif
 
+  #if HAS_LCD_BRIGHTNESS
+    static void M256();
+  #endif
+
   #if ENABLED(EXPERIMENTAL_I2CBUS)
     static void M260();
     static void M261();

Marlin/src/gcode/lcd/M256.cpp

+/**
+ * Marlin 3D Printer Firmware
+ * Copyright (c) 2021 MarlinFirmware [https://github.com/MarlinFirmware/Marlin]
+ *
+ * Based on Sprinter and grbl.
+ * Copyright (c) 2011 Camiel Gubbels / Erik van der Zalm
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+#include "../../inc/MarlinConfig.h"
+
+#if HAS_LCD_BRIGHTNESS
+
+#include "../gcode.h"
+#include "../../lcd/marlinui.h"
+
+/**
+ * M256: Set the LCD brightness
+ */
+void GcodeSuite::M256() {
+  if (parser.seenval('B')) ui.set_brightness(parser.value_int());
+  SERIAL_ECHOLNPAIR("LCD Brightness: ", ui.brightness);
+}
+
+#endif // HAS_LCD_BRIGHTNESS

Marlin/src/gcode/lcd/M73.cpp

  *   M73 P25 ; Set progress to 25%
  */
 void GcodeSuite::M73() {
-  if (parser.seen('P'))
+  if (parser.seenval('P'))
     ui.set_progress((PROGRESS_SCALE) > 1
       ? parser.value_float() * (PROGRESS_SCALE)
       : parser.value_byte()
     );
   #if BOTH(LCD_SET_PROGRESS_MANUALLY, USE_M73_REMAINING_TIME)
-    if (parser.seen('R')) ui.set_remaining_time(60 * parser.value_ulong());
+    if (parser.seenval('R')) ui.set_remaining_time(60 * parser.value_ulong());
   #endif
 }
 

Marlin/src/lcd/marlinui.cpp

   }
 #endif
 
+#if HAS_LCD_BRIGHTNESS
+  uint8_t MarlinUI::brightness = DEFAULT_LCD_BRIGHTNESS;
+  bool MarlinUI::backlight = true;
+
+  void MarlinUI::set_brightness(const uint8_t value) {
+    backlight = !!value;
+    if (backlight) brightness = constrain(value, MIN_LCD_BRIGHTNESS, MAX_LCD_BRIGHTNESS);
+    // Set brightness on enabled LCD here
+  }
+#endif
+
 #if ENABLED(SOUND_MENU_ITEM)
   bool MarlinUI::buzzer_enabled = true;
 #endif

Marlin/src/lcd/marlinui.h

     static void media_changed(const uint8_t old_stat, const uint8_t stat);
   #endif
 
+  #if HAS_LCD_BRIGHTNESS
+    #ifndef MIN_LCD_BRIGHTNESS
+      #define MIN_LCD_BRIGHTNESS   1
+    #endif
+    #ifndef MAX_LCD_BRIGHTNESS
+      #define MAX_LCD_BRIGHTNESS 255
+    #endif
+    #ifndef DEFAULT_LCD_BRIGHTNESS
+      #define DEFAULT_LCD_BRIGHTNESS MAX_LCD_BRIGHTNESS
+    #endif
+    static uint8_t brightness;
+    static bool backlight;
+    static void set_brightness(const uint8_t value);
+    FORCE_INLINE static void refresh_brightness() { set_brightness(brightness); }
+  #endif
+
   #if ENABLED(DWIN_CREALITY_LCD)
     static void refresh();
   #else

Marlin/src/module/settings.cpp

  */
 
 // Change EEPROM version if the structure changes
-#define EEPROM_VERSION "V83"
+#define EEPROM_VERSION "V84"
 #define EEPROM_OFFSET 100
 
 // Check the integrity of data offsets.
   int16_t lcd_contrast;                                 // M250 C
 
   //
+  // HAS_LCD_BRIGHTNESS
+  //
+  uint8_t lcd_brightness;                               // M256 B
+
+  //
   // Controller fan settings
   //
   controllerFan_settings_t controllerFan_settings;      // M710
     //
     {
       _FIELD_TEST(lcd_contrast);
-
-      const int16_t lcd_contrast =
-        #if HAS_LCD_CONTRAST
-          ui.contrast
-        #else
-          127
-        #endif
-      ;
+      const int16_t lcd_contrast = TERN(HAS_LCD_CONTRAST, ui.contrast, 127);
       EEPROM_WRITE(lcd_contrast);
     }
 
     //
+    // LCD Brightness
+    //
+    {
+      _FIELD_TEST(lcd_brightness);
+      const uint8_t lcd_brightness = TERN(HAS_LCD_BRIGHTNESS, ui.brightness, 255);
+      EEPROM_WRITE(lcd_brightness);
+    }
+
+    //
     // Controller Fan
     //
     {
       }
 
       //
+      // LCD Brightness
+      //
+      {
+        _FIELD_TEST(lcd_brightness);
+        uint8_t lcd_brightness;
+        EEPROM_READ(lcd_brightness);
+        TERN_(HAS_LCD_BRIGHTNESS, if (!validating) ui.set_brightness(lcd_brightness));
+      }
+
+      //
       // Controller Fan
       //
       {
   TERN_(HAS_LCD_CONTRAST, ui.set_contrast(DEFAULT_LCD_CONTRAST));
 
   //
+  // LCD Brightness
+  //
+  TERN_(HAS_LCD_BRIGHTNESS, ui.set_brightness(DEFAULT_LCD_BRIGHTNESS));
+
+  //
   // Controller Fan
   //
   TERN_(USE_CONTROLLER_FAN, controllerFan.reset());
       CONFIG_ECHO_MSG("  M250 C", ui.contrast);
     #endif
 
+    #if HAS_LCD_BRIGHTNESS
+      CONFIG_ECHO_HEADING("LCD Brightness:");
+      CONFIG_ECHO_MSG("  M256 B", ui.brightness);
+    #endif
+
     TERN_(CONTROLLER_FAN_EDITABLE, M710_report(forReplay));
 
     #if ENABLED(POWER_LOSS_RECOVERY)

Marlin/src/module/stepper/trinamic.cpp

     TMC_SW_DETAIL(Y), TMC_SW_DETAIL(Y2),
     TMC_SW_DETAIL(Z), TMC_SW_DETAIL(Z2), TMC_SW_DETAIL(Z3), TMC_SW_DETAIL(Z4),
     TMC_SW_DETAIL(I), TMC_SW_DETAIL(J), TMC_SW_DETAIL(K),
-  	TMC_SW_DETAIL(E0), TMC_SW_DETAIL(E1), TMC_SW_DETAIL(E2), TMC_SW_DETAIL(E3), TMC_SW_DETAIL(E4), TMC_SW_DETAIL(E5), TMC_SW_DETAIL(E6), TMC_SW_DETAIL(E7)
+    TMC_SW_DETAIL(E0), TMC_SW_DETAIL(E1), TMC_SW_DETAIL(E2), TMC_SW_DETAIL(E3), TMC_SW_DETAIL(E4), TMC_SW_DETAIL(E5), TMC_SW_DETAIL(E6), TMC_SW_DETAIL(E7)
   };
 
   constexpr bool sc_sw_done(size_t start, size_t end) { return start == end; }

ini/features.ini

 HAS_RESUME_CONTINUE                    = src_filter=+<src/gcode/lcd/M0_M1.cpp>
 HAS_STATUS_MESSAGE                     = src_filter=+<src/gcode/lcd/M117.cpp>
 HAS_LCD_CONTRAST                       = src_filter=+<src/gcode/lcd/M250.cpp>
+HAS_LCD_BRIGHTNESS                     = src_filter=+<src/gcode/lcd/M256.cpp>
 HAS_BUZZER                             = src_filter=+<src/gcode/lcd/M300.cpp>
 LCD_SET_PROGRESS_MANUALLY              = src_filter=+<src/gcode/lcd/M73.cpp>
 TOUCH_SCREEN_CALIBRATION               = src_filter=+<src/gcode/lcd/M995.cpp>

platformio.ini

   -<src/gcode/host/M876.cpp>
   -<src/gcode/lcd/M0_M1.cpp>
   -<src/gcode/lcd/M117.cpp>
-  -<src/gcode/lcd/M250.cpp>
+  -<src/gcode/lcd/M250.cpp> -<src/gcode/lcd/M256.cpp>
   -<src/gcode/lcd/M300.cpp>
   -<src/gcode/lcd/M414.cpp>
   -<src/gcode/lcd/M73.cpp>