drm/i915/dsi: start using enum mipi_dsi_pixel_format

A small step moving us closer to DRM MIPI DSI code. Use enum
mipi_dsi_pixel_format instead of our own. The first benefit is being
able to use common mipi_dsi_pixel_format_to_bpp().

There's a little back and forth conversion with the VBT -> enum ->
register, since we have just shoved the VBT value into the register
directly. Longer term, all the VBT parsing and deciphering should be
done in intel_bios.c, and abstracted there.

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1458123700-16003-2-git-send-email-jani.nikula@intel.com
diff --git a/drivers/gpu/drm/i915/intel_dsi.h b/drivers/gpu/drm/i915/intel_dsi.h
index 92f3922..54f072c 100644
--- a/drivers/gpu/drm/i915/intel_dsi.h
+++ b/drivers/gpu/drm/i915/intel_dsi.h
@@ -34,8 +34,6 @@
 #define DSI_DUAL_LINK_FRONT_BACK	1
 #define DSI_DUAL_LINK_PIXEL_ALT		2
 
-int dsi_pixel_format_bpp(int pixel_format);
-
 struct intel_dsi_host;
 
 struct intel_dsi {
@@ -64,8 +62,12 @@
 	/* number of DSI lanes */
 	unsigned int lane_count;
 
-	/* video mode pixel format for MIPI_DSI_FUNC_PRG register */
-	u32 pixel_format;
+	/*
+	 * video mode pixel format
+	 *
+	 * XXX: consolidate on .format in struct mipi_dsi_device.
+	 */
+	enum mipi_dsi_pixel_format pixel_format;
 
 	/* video mode format for MIPI_VIDEO_MODE_FORMAT register */
 	u32 video_mode_format;