[PATCH v2 1/4] drm/bridge: nwl-dsi: Limit LCDIF specific sync override

When using DCSS with NWL, overriding the mode flags to enforce active high
sync is preventing the use of active low with downstream bridges, such as
ti-sn65dsi83, which will not see such mode flags set by the panel.

Signed-off-by: Esben Haabendal <[email protected]>
---
 drivers/gpu/drm/bridge/nwl-dsi.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
index 3c9ae93c4f67..915e1bdc73c8 100644
--- a/drivers/gpu/drm/bridge/nwl-dsi.c
+++ b/drivers/gpu/drm/bridge/nwl-dsi.c
@@ -110,6 +110,8 @@ struct nwl_dsi {
 	int error;
 
 	struct nwl_dsi_transfer *xfer;
+
+	unsigned int endpoint;
 };
 
 static const struct regmap_config nwl_dsi_regmap_config = {
@@ -821,10 +823,13 @@ static int nwl_dsi_bridge_atomic_check(struct drm_bridge *bridge,
 				       struct drm_connector_state *conn_state)
 {
 	struct drm_display_mode *adjusted_mode = &crtc_state->adjusted_mode;
+	struct nwl_dsi *dsi = bridge_to_dsi(bridge);
 
 	/* 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);
+	if (dsi->endpoint == NWL_DSI_ENDPOINT_LCDIF) {
+		adjusted_mode->flags |= (DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC);
+		adjusted_mode->flags &= ~(DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC);
+	}
 
 	/*
 	 * Do a full modeset if crtc_state->active is changed to be true.
@@ -1088,13 +1093,12 @@ static int nwl_dsi_parse_dt(struct nwl_dsi *dsi)
 static int nwl_dsi_select_input(struct nwl_dsi *dsi)
 {
 	struct device_node *remote;
-	u32 use_dcss = 1;
 	int ret;
 
 	remote = of_graph_get_remote_node(dsi->dev->of_node, 0,
 					  NWL_DSI_ENDPOINT_LCDIF);
 	if (remote) {
-		use_dcss = 0;
+		dsi->endpoint = NWL_DSI_ENDPOINT_LCDIF;
 	} else {
 		remote = of_graph_get_remote_node(dsi->dev->of_node, 0,
 						  NWL_DSI_ENDPOINT_DCSS);
@@ -1103,11 +1107,12 @@ static int nwl_dsi_select_input(struct nwl_dsi *dsi)
 				      "No valid input endpoint found\n");
 			return -EINVAL;
 		}
+		dsi->endpoint = NWL_DSI_ENDPOINT_DCSS;
 	}
 
 	DRM_DEV_INFO(dsi->dev, "Using %s as input source\n",
-		     (use_dcss) ? "DCSS" : "LCDIF");
-	ret = mux_control_try_select(dsi->mux, use_dcss);
+		     (dsi->endpoint == NWL_DSI_ENDPOINT_DCSS) ? "DCSS" : "LCDIF");
+	ret = mux_control_try_select(dsi->mux, dsi->endpoint == NWL_DSI_ENDPOINT_DCSS);
 	if (ret < 0)
 		DRM_DEV_ERROR(dsi->dev, "Failed to select input: %d\n", ret);
 

-- 
2.55.0