drm/panel: lvds: Use bus_flags from DT panel-timing property

This driver currently rewrites bus_flags based solely on the value of
DT property 'data-mirror' and ignores bus_flags which might have been
set in DT panel-timing node. Specificaly, the 'de-active' DT property
sets DRM_BUS_FLAG_DE_ bus_flags.

Since of_get_drm_panel_display_mode() conveniently parses the bus_flags
out of DT panel-timing property, just ORR them with bus_flags inferred
from 'data-mirror' DT property and use the result as panel bus_flags.

This fixes handling of panels with 'panel-timing { de-active = <1>; };'.
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Christoph Niedermaier <cniedermaier@dh-electronics.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Dmitry Osipenko <digetx@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Robert Foss <robert.foss@linaro.org>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
To: dri-devel@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20220401162154.295152-2-marex@denx.de

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

@@ -33,7 +33,6 @@ struct panel_lvds {
 	struct drm_display_mode dmode;
 	u32 bus_flags;
 	unsigned int bus_format;
-	bool data_mirror;
 
 	struct regulator *supply;
 
@@ -99,9 +98,7 @@ static int panel_lvds_get_modes(struct drm_panel *panel,
 	connector->display_info.height_mm = lvds->dmode.height_mm;
 	drm_display_info_set_bus_formats(&connector->display_info,
 					 &lvds->bus_format, 1);
-	connector->display_info.bus_flags = lvds->data_mirror
-					  ? DRM_BUS_FLAG_DATA_LSB_TO_MSB
-					  : DRM_BUS_FLAG_DATA_MSB_TO_LSB;
+	connector->display_info.bus_flags = lvds->bus_flags;
 	drm_connector_set_panel_orientation(connector, lvds->orientation);
 
 	return 1;
@@ -154,7 +151,9 @@ static int panel_lvds_parse_dt(struct panel_lvds *lvds)
 
 	lvds->bus_format = ret;
 
-	lvds->data_mirror = of_property_read_bool(np, "data-mirror");
+	lvds->bus_flags |= of_property_read_bool(np, "data-mirror") ?
+			   DRM_BUS_FLAG_DATA_LSB_TO_MSB :
+			   DRM_BUS_FLAG_DATA_MSB_TO_LSB;
 
 	return 0;
 }