drm: introduce bus_flags in drm_display_info

Introduce bus_flags to specify display bus properties like signal
polarities. This is useful for parallel display buses, e.g. to
specify the pixel clock or data enable polarity.

Suggested-by: Thierry Reding <thierry.reding@gmail.com>
Acked-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Stefan Agner <stefan@agner.ch>

drivers/gpu/drm/panel/panel-simple.c

@@ -72,6 +72,7 @@ struct panel_desc {
 	} delay;
 
 	u32 bus_format;
+	u32 bus_flags;
 };
 
 struct panel_simple {
@@ -144,6 +145,7 @@ static int panel_simple_get_fixed_modes(struct panel_simple *panel)
 	if (panel->desc->bus_format)
 		drm_display_info_set_bus_formats(&connector->display_info,
 						 &panel->desc->bus_format, 1);
+	connector->display_info.bus_flags = panel->desc->bus_flags;
 
 	return num;
 }

include/drm/drm_crtc.h

@@ -118,6 +118,14 @@ enum subpixel_order {
 #define DRM_COLOR_FORMAT_RGB444		(1<<0)
 #define DRM_COLOR_FORMAT_YCRCB444	(1<<1)
 #define DRM_COLOR_FORMAT_YCRCB422	(1<<2)
+
+#define DRM_BUS_FLAG_DE_LOW		(1<<0)
+#define DRM_BUS_FLAG_DE_HIGH		(1<<1)
+/* drive data on pos. edge */
+#define DRM_BUS_FLAG_PIXDATA_POSEDGE	(1<<2)
+/* drive data on neg. edge */
+#define DRM_BUS_FLAG_PIXDATA_NEGEDGE	(1<<3)
+
 /*
  * Describes a given display (e.g. CRT or flat panel) and its limitations.
  */
@@ -139,6 +147,7 @@ struct drm_display_info {
 
 	const u32 *bus_formats;
 	unsigned int num_bus_formats;
+	u32 bus_flags;
 
 	/* Mask of supported hdmi deep color modes */
 	u8 edid_hdmi_dc_modes;