Module17: removed screen contrast setting, added screen brightness setting

Module17 uses an OLED display, which does not have contrast regulation. The
contrast control register, however, allows to change the brightness of the
display.

openrtx/include/ui/ui_mod17.h

@@ -108,13 +108,8 @@ enum backupRestoreItems
 
 enum displayItems
 {
-#ifdef CONFIG_SCREEN_CONTRAST
-    D_CONTRAST = 0
-    ,D_TIMER
-#endif
-#ifndef CONFIG_SCREEN_CONTRAST
-    D_TIMER = 0
-#endif
+    D_BRIGHTNESS = 0,
+    D_TIMER
 };
 
 #ifdef CONFIG_GPS

openrtx/src/ui/module17/ui.c

@@ -88,9 +88,7 @@ const char *settings_items[] =
 
 const char *display_items[] =
 {
-#ifdef CONFIG_SCREEN_CONTRAST
-    "Contrast",
-#endif
+    "Brightness",
     "Timer"
 };
 
@@ -502,15 +500,18 @@ void _ui_fsm_insertVFONumber(kbd_msg_t msg, bool *sync_rtx)
     }
 }
 
-void _ui_changeContrast(int variation)
+static void _ui_changeBrightness(int variation)
 {
-    if(variation >= 0)
-        state.settings.contrast =
-        (255 - state.settings.contrast < variation) ? 255 : state.settings.contrast + variation;
-    else
-        state.settings.contrast =
-        (state.settings.contrast < -variation) ? 0 : state.settings.contrast + variation;
-    display_setContrast(state.settings.contrast);
+    // Avoid rollover if current value is zero.
+    if((state.settings.brightness == 0) && (variation < 0))
+        return;
+
+    // Cap max brightness to 100
+    if((state.settings.brightness == 100) && (variation > 0))
+        return;
+
+    state.settings.brightness += variation;
+    display_setBacklightLevel(state.settings.brightness);
 }
 
 void _ui_changeTimer(int variation)
@@ -929,11 +930,9 @@ void ui_updateFSM(bool *sync_rtx)
                 {
                     switch(ui_state.menu_selected)
                     {
-#ifdef CONFIG_SCREEN_CONTRAST
-                        case D_CONTRAST:
-                            _ui_changeContrast(-4);
+                        case D_BRIGHTNESS:
+                            _ui_changeBrightness(-5);
                             break;
-#endif
                         case D_TIMER:
                             _ui_changeTimer(-1);
                             break;
@@ -945,11 +944,9 @@ void ui_updateFSM(bool *sync_rtx)
                 {
                     switch(ui_state.menu_selected)
                     {
-#ifdef CONFIG_SCREEN_CONTRAST
-                        case D_CONTRAST:
-                            _ui_changeContrast(+4);
+                        case D_BRIGHTNESS:
+                            _ui_changeBrightness(+5);
                             break;
-#endif
                         case D_TIMER:
                             _ui_changeTimer(+1);
                             break;

openrtx/src/ui/module17/ui_menu.c

@@ -177,11 +177,9 @@ int _ui_getDisplayValueName(char *buf, uint8_t max_len, uint8_t index)
     uint8_t value = 0;
     switch(index)
     {
-#ifdef CONFIG_SCREEN_CONTRAST
-        case D_CONTRAST:
-            value = last_state.settings.contrast;
+        case D_BRIGHTNESS:
+            value = last_state.settings.brightness;
             break;
-#endif
         case D_TIMER:
             snprintf(buf, max_len, "%s",
                      display_timer_values[last_state.settings.display_timer]);

platform/drivers/display/SH110x_Mod17.c

@@ -122,16 +122,24 @@ void display_render(void *fb)
 
 void display_setContrast(uint8_t contrast)
 {
-    gpio_clearPin(LCD_CS);
-
-    gpio_clearPin(LCD_RS);             /* RS low -> command mode              */
-    (void) spi2_sendRecv(0x81);        /* Set Electronic Volume               */
-    (void) spi2_sendRecv(contrast);    /* Controller contrast range is 0 - 63 */
-
-    gpio_setPin(LCD_CS);
+    /* OLED display do not have contrast regulation */
+    (void) contrast;
 }
 
 void display_setBacklightLevel(uint8_t level)
 {
-    (void) level;
+    /*
+     * Module17 uses an OLED display, so contrast channel is actually controlling
+     * the brightness. The usable range is 0 - 128, above which there is no
+     * noticeable change in the brightness level (already at maximum).
+     */
+    uint16_t bl = (level * 128) / 100;
+
+    gpio_clearPin(LCD_CS);
+
+    gpio_clearPin(LCD_RS);             /* RS low -> command mode    */
+    (void) spi2_sendRecv(0x81);        /* Contrast control register */
+    (void) spi2_sendRecv(bl);
+
+    gpio_setPin(LCD_CS);
 }

platform/targets/Module17/hwconfig.h

@@ -29,10 +29,6 @@
 #define CONFIG_SCREEN_WIDTH 128
 #define CONFIG_SCREEN_HEIGHT 64
 
-/* Screen has adjustable contrast */
-#define CONFIG_SCREEN_CONTRAST
-#define CONFIG_DEFAULT_CONTRAST 91
-
 /* Screen pixel format */
 #define CONFIG_PIX_FMT_BW