OMAPDSS: DISPC: Add writeback register offsets and dss features structs

Since writeback has many overlay like properties, and most of it's registers are
similar to that of overlays, it's possible to reuse most of the overlay related
DISPC code for writeback when considering it as a plane. Writeback was added as
a plane in the omap_plane field as OMAP_DSS_WB.

Add the writeback register offsets in dispc.h, add minimal WB plane related info
needed in dss_features. Add a function which returns the number of writeback
pipelines an OMAP version has.

Signed-off-by: Archit Taneja <archit@ti.com>
diff --git a/drivers/video/omap2/dss/dss_features.c b/drivers/video/omap2/dss/dss_features.c
index 5a5c25b..acbc1e1 100644
--- a/drivers/video/omap2/dss/dss_features.c
+++ b/drivers/video/omap2/dss/dss_features.c
@@ -46,6 +46,7 @@
 
 	const int num_mgrs;
 	const int num_ovls;
+	const int num_wbs;
 	const enum omap_display_type *supported_displays;
 	const enum omap_dss_output_id *supported_outputs;
 	const enum omap_color_mode *supported_color_modes;
@@ -310,6 +311,16 @@
 	OMAP_DSS_COLOR_ARGB16 | OMAP_DSS_COLOR_XRGB16_1555 |
 	OMAP_DSS_COLOR_ARGB32 | OMAP_DSS_COLOR_RGBX16 |
 	OMAP_DSS_COLOR_RGBX32,
+
+	/* OMAP_DSS_WB */
+	OMAP_DSS_COLOR_RGB16 | OMAP_DSS_COLOR_RGB12U |
+	OMAP_DSS_COLOR_YUV2 | OMAP_DSS_COLOR_ARGB16_1555 |
+	OMAP_DSS_COLOR_RGBA32 | OMAP_DSS_COLOR_NV12 |
+	OMAP_DSS_COLOR_RGBA16 | OMAP_DSS_COLOR_RGB24U |
+	OMAP_DSS_COLOR_RGB24P | OMAP_DSS_COLOR_UYVY |
+	OMAP_DSS_COLOR_ARGB16 | OMAP_DSS_COLOR_XRGB16_1555 |
+	OMAP_DSS_COLOR_ARGB32 | OMAP_DSS_COLOR_RGBX16 |
+	OMAP_DSS_COLOR_RGBX32,
 };
 
 static const enum omap_overlay_caps omap2_dss_overlay_caps[] = {
@@ -710,6 +721,7 @@
 
 	.num_mgrs = 3,
 	.num_ovls = 4,
+	.num_wbs = 1,
 	.supported_displays = omap4_dss_supported_displays,
 	.supported_outputs = omap4_dss_supported_outputs,
 	.supported_color_modes = omap4_dss_supported_color_modes,
@@ -731,6 +743,7 @@
 
 	.num_mgrs = 3,
 	.num_ovls = 4,
+	.num_wbs = 1,
 	.supported_displays = omap4_dss_supported_displays,
 	.supported_outputs = omap4_dss_supported_outputs,
 	.supported_color_modes = omap4_dss_supported_color_modes,
@@ -752,6 +765,7 @@
 
 	.num_mgrs = 3,
 	.num_ovls = 4,
+	.num_wbs = 1,
 	.supported_displays = omap4_dss_supported_displays,
 	.supported_outputs = omap4_dss_supported_outputs,
 	.supported_color_modes = omap4_dss_supported_color_modes,
@@ -829,6 +843,11 @@
 	return omap_current_dss_features->num_ovls;
 }
 
+int dss_feat_get_num_wbs(void)
+{
+	return omap_current_dss_features->num_wbs;
+}
+
 unsigned long dss_feat_get_param_min(enum dss_range_param param)
 {
 	return omap_current_dss_features->dss_params[param].min;