drm/amd/display: Convert connector signal id to string

To improve the readability of the of the log, this commit introduces a
function that converts the signal type id to a human-readable string.
Reviewed-by: Jerry Zuo <jerry.zuo@amd.com>
Acked-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Rodrigo Siqueira <rodrigo.siqueira@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/link/link_factory.c

@@ -563,11 +563,9 @@ static bool construct_phy(struct dc_link *link,
 		goto create_fail;
 	}
 
-	/* TODO: #DAL3 Implement id to str function.*/
-	LINK_INFO("Connector[%d] description:"
-		  "signal %d\n",
+	LINK_INFO("Connector[%d] description: signal: %s\n",
 		  init_params->connector_index,
-		  link->connector_signal);
+		  signal_type_to_string(link->connector_signal));
 
 	ddc_service_init_data.ctx = link->ctx;
 	ddc_service_init_data.id = link->link_id;

drivers/gpu/drm/amd/display/include/signal_types.h

@@ -44,6 +44,34 @@ enum signal_type {
 	SIGNAL_TYPE_VIRTUAL		= (1 << 9),	/* Virtual Display */
 };
 
+static inline const char *signal_type_to_string(const int type)
+{
+	switch (type) {
+	case SIGNAL_TYPE_NONE:
+		return "No signal";
+	case SIGNAL_TYPE_DVI_SINGLE_LINK:
+		return "DVI: Single Link";
+	case SIGNAL_TYPE_DVI_DUAL_LINK:
+		return "DVI: Dual Link";
+	case SIGNAL_TYPE_HDMI_TYPE_A:
+		return "HDMI: TYPE A";
+	case SIGNAL_TYPE_LVDS:
+		return "LVDS";
+	case SIGNAL_TYPE_RGB:
+		return "RGB";
+	case SIGNAL_TYPE_DISPLAY_PORT:
+		return "Display Port";
+	case SIGNAL_TYPE_DISPLAY_PORT_MST:
+		return "Display Port: MST";
+	case SIGNAL_TYPE_EDP:
+		return "Embedded Display Port";
+	case SIGNAL_TYPE_VIRTUAL:
+		return "Virtual";
+	default:
+		return "Unknown";
+	}
+}
+
 /* help functions for signal types manipulation */
 static inline bool dc_is_hdmi_tmds_signal(enum signal_type signal)
 {