drivers: display: Introduce Greyscale pixel format

This introduces greyscale Luminance 8 pixel format

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

Author: VynDragon

include/zephyr/drivers/display.h

@@ -46,6 +46,8 @@ enum display_pixel_format {
 	PIXEL_FORMAT_ARGB_8888		= BIT(3), /**< 32-bit ARGB */
 	PIXEL_FORMAT_RGB_565		= BIT(4), /**< 16-bit RGB */
 	PIXEL_FORMAT_BGR_565		= BIT(5), /**< 16-bit BGR */
+	PIXEL_FORMAT_L_8		= BIT(6), /**< 8-bit Grayscale/Luminance, equivalent to */
+						  /**< GRAY, GREY, GRAY8, Y8, R8, etc...        */
 };
 
 /**
@@ -61,7 +63,8 @@ enum display_pixel_format {
 	(((fmt & PIXEL_FORMAT_MONO10) >> 2) * 1U) +				\
 	(((fmt & PIXEL_FORMAT_ARGB_8888) >> 3) * 32U) +				\
 	(((fmt & PIXEL_FORMAT_RGB_565) >> 4) * 16U) +				\
-	(((fmt & PIXEL_FORMAT_BGR_565) >> 5) * 16U))
+	(((fmt & PIXEL_FORMAT_BGR_565) >> 5) * 16U) +				\
+	(((fmt & PIXEL_FORMAT_L_8) >> 6) * 8U))
 
 /**
  * @brief Display screen information

include/zephyr/dt-bindings/display/panel.h

@@ -23,12 +23,13 @@
  * since enum definitions are not supported by devicetree tooling.
  */
 
-#define PANEL_PIXEL_FORMAT_RGB_888		(0x1 << 0)
-#define PANEL_PIXEL_FORMAT_MONO01		(0x1 << 1) /* 0=Black 1=White */
-#define PANEL_PIXEL_FORMAT_MONO10		(0x1 << 2) /* 1=Black 0=White */
-#define PANEL_PIXEL_FORMAT_ARGB_8888		(0x1 << 3)
-#define PANEL_PIXEL_FORMAT_RGB_565		(0x1 << 4)
-#define PANEL_PIXEL_FORMAT_BGR_565		(0x1 << 5)
+#define PANEL_PIXEL_FORMAT_RGB_888   (0x1 << 0)
+#define PANEL_PIXEL_FORMAT_MONO01    (0x1 << 1) /* 0=Black 1=White */
+#define PANEL_PIXEL_FORMAT_MONO10    (0x1 << 2) /* 1=Black 0=White */
+#define PANEL_PIXEL_FORMAT_ARGB_8888 (0x1 << 3)
+#define PANEL_PIXEL_FORMAT_RGB_565   (0x1 << 4)
+#define PANEL_PIXEL_FORMAT_BGR_565   (0x1 << 5)
+#define PANEL_PIXEL_FORMAT_L_8       (0x1 << 6)
 
 /**
  * @}