nwl-dsi: fixup mode only for LCDIF input, not DCSS

[Lukas F. Hartmann]

The fixup of HSYNC and VSYNC should not be done when the input source is
DCSS, or internal display does not work on MNT Reform 2 (open hardware 
laptop based on NXP i.MX8M using DCSS->DSI->eDP for internal display).

Signed-off-by: Lukas F. Hartmann <lukas at mntre.com>
---
 drivers/gpu/drm/bridge/nwl-dsi.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index 66b67402f..6735ab2a2 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -807,10 +807,16 @@ static bool nwl_dsi_bridge_mode_fixup(struct drm_bridge *bridge,
 				      const struct drm_display_mode *mode,
 				      struct drm_display_mode *adjusted_mode)
 {
-	/* At least LCDIF + NWL needs active high sync */
-	adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
-	adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
+	struct device_node *remote;
+	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
+
+	remote = of_graph_get_remote_node(dsi->dev->of_node, 0,
+						NWL_DSI_ENDPOINT_LCDIF);
+	if (remote) {
+		/* At least LCDIF + NWL needs active high sync */
+		adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
+		adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
+	}

 	return true;
 }
--
2.28.0