drm/msm/dp: Add support for determining the eDP/DP mode from DT

Instead of relying on different compatibles for eDP and DP, lookup
the panel node in devicetree to figure out the connector type and
then pass on that information to the PHY. External DP doesn't have
a panel described in DT, therefore, assume it's eDP if panel node
is present.
Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Bjorn Andersson <quic_bjorande@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/584534/
Link: https://lore.kernel.org/r/20240324-x1e80100-display-refactor-connector-v4-1-e0ebaea66a78@linaro.orgSigned-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>

drivers/gpu/drm/msm/dp/dp_display.c

@@ -728,6 +728,14 @@ static int dp_init_sub_modules(struct dp_display_private *dp)
 	if (IS_ERR(phy))
 		return PTR_ERR(phy);
 
+	rc = phy_set_mode_ext(phy, PHY_MODE_DP,
+			      dp->dp_display.is_edp ? PHY_SUBMODE_EDP : PHY_SUBMODE_DP);
+	if (rc) {
+		DRM_ERROR("failed to set phy submode, rc = %d\n", rc);
+		dp->catalog = NULL;
+		goto error;
+	}
+
 	dp->catalog = dp_catalog_get(dev);
 	if (IS_ERR(dp->catalog)) {
 		rc = PTR_ERR(dp->catalog);
@@ -1243,6 +1251,25 @@ static int dp_auxbus_done_probe(struct drm_dp_aux *aux)
 	return dp_display_probe_tail(aux->dev);
 }
 
+static int dp_display_get_connector_type(struct platform_device *pdev,
+					 const struct msm_dp_desc *desc)
+{
+	struct device_node *node = pdev->dev.of_node;
+	struct device_node *aux_bus = of_get_child_by_name(node, "aux-bus");
+	struct device_node *panel = of_get_child_by_name(aux_bus, "panel");
+	int connector_type;
+
+	if (panel)
+		connector_type = DRM_MODE_CONNECTOR_eDP;
+	else
+		connector_type = DRM_MODE_SUBCONNECTOR_DisplayPort;
+
+	of_node_put(panel);
+	of_node_put(aux_bus);
+
+	return connector_type;
+}
+
 static int dp_display_probe(struct platform_device *pdev)
 {
 	int rc = 0;
@@ -1265,7 +1292,7 @@ static int dp_display_probe(struct platform_device *pdev)
 	dp->dp_display.pdev = pdev;
 	dp->name = "drm_dp";
 	dp->id = desc->id;
-	dp->dp_display.connector_type = desc->connector_type;
+	dp->dp_display.connector_type = dp_display_get_connector_type(pdev, desc);
 	dp->wide_bus_supported = desc->wide_bus_supported;
 	dp->dp_display.is_edp =
 		(dp->dp_display.connector_type == DRM_MODE_CONNECTOR_eDP);