tests: Introduce greyscale-related tests modifications

This introduces greyscale-related changes to tests

Signed-off-by: Camille BAUD <mail@massdriver.space>

Author: VynDragon

tests/drivers/display/display_read_write/src/main.c

@@ -34,6 +34,7 @@ static inline uint8_t bytes_per_pixel(enum display_pixel_format pixel_format)
 	case PIXEL_FORMAT_RGB_565:
 	case PIXEL_FORMAT_BGR_565:
 		return 2;
+	case PIXEL_FORMAT_L_8:
 	case PIXEL_FORMAT_MONO01:
 	case PIXEL_FORMAT_MONO10:
 	default:

tests/lib/gui/lvgl/src/main.c

@@ -104,8 +104,9 @@ void *setup_lvgl(void)
 
 #if CONFIG_LV_COLOR_DEPTH_1 == 1
 	display_set_pixel_format(display_dev, PIXEL_FORMAT_MONO10);
-#elif CONFIG_LV_COLOR_DEPTH_8 == 1 || CONFIG_LV_COLOR_DEPTH_24 == 1
-	/* No 8bit display pixel format not supported */
+#elif CONFIG_LV_COLOR_DEPTH_8 == 1
+	display_set_pixel_format(display_dev, PIXEL_FORMAT_L_8);
+#elif CONFIG_LV_COLOR_DEPTH_24 == 1
 	display_set_pixel_format(display_dev, PIXEL_FORMAT_RGB_888);
 #elif CONFIG_LV_COLOR_DEPTH_16 == 1
 	display_set_pixel_format(display_dev, PIXEL_FORMAT_RGB_565);