drm/omap: dsi: use separate VCs for cmd and video

For command mode panels we can use a single VC for sending command and
video data, even if we have to change the data source for that VC when
going from command to video or vice versa.

However, with video mode panels we want to keep the pixel data VC
enabled, and use another VC for command data, and the commands will get
interleaved into the pixel data.

This patch makes the driver use VC0 for commands and VC1 for video.
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201215104657.802264-71-tomi.valkeinen@ti.com

drivers/gpu/drm/omapdrm/dss/dsi.c

@@ -452,7 +452,9 @@ static bool dsi_perf;
 module_param(dsi_perf, bool, 0644);
 #endif
 
-#define VC_DEFAULT 0
+/* Note: for some reason video mode seems to work only if VC_VIDEO is 0 */
+#define VC_VIDEO	0
+#define VC_CMD		1
 
 #define drm_bridge_to_dsi(bridge) \
 	container_of(bridge, struct dsi_data, bridge)
@@ -3725,7 +3727,7 @@ static void dsi_disable_video_outputs(struct omap_dss_device *dssdev)
 	dsi_bus_lock(dsi);
 	dsi->video_enabled = false;
 
-	dsi_disable_video_output(dssdev, VC_DEFAULT);
+	dsi_disable_video_output(dssdev, VC_VIDEO);
 
 	dsi_display_disable(dssdev);
 
@@ -3948,7 +3950,7 @@ static int dsi_update_channel(struct omap_dss_device *dssdev, int vc)
 
 static int dsi_update_all(struct omap_dss_device *dssdev)
 {
-	return dsi_update_channel(dssdev, VC_DEFAULT);
+	return dsi_update_channel(dssdev, VC_VIDEO);
 }
 
 /* Display funcs */
@@ -4181,7 +4183,7 @@ static void dsi_enable_video_outputs(struct omap_dss_device *dssdev)
 
 	dsi_display_enable(dssdev);
 
-	dsi_enable_video_output(dssdev, VC_DEFAULT);
+	dsi_enable_video_output(dssdev, VC_VIDEO);
 
 	dsi->video_enabled = true;
 
@@ -4938,7 +4940,7 @@ static ssize_t omap_dsi_host_transfer(struct mipi_dsi_host *host,
 {
 	struct dsi_data *dsi = host_to_omap(host);
 	int r;
-	int vc = VC_DEFAULT;
+	int vc = VC_CMD;
 
 	dsi_bus_lock(dsi);