disp: msm: dsi: Add a new DT property panel test pin

This pin is a output pin from panel. Panel can
output signal of internal VSYNC and ERR_FLAG.

Change-Id: Ib8e661ca1fdb33bb7060935edb9bc1f1a858c4b3
Signed-off-by: Yuan Zhao <yzhao@codeaurora.org>

msm/dsi/dsi_panel.c

@@ -2135,6 +2135,13 @@ static int dsi_panel_parse_gpios(struct dsi_panel *panel)
 		goto error;
 	}
 
+	panel->panel_test_gpio = utils->get_named_gpio(utils->data,
+					"qcom,mdss-dsi-panel-test-pin",
+					0);
+	if (!gpio_is_valid(panel->panel_test_gpio))
+		pr_debug("%s:%d panel test gpio not specified\n", __func__,
+			 __LINE__);
+
 error:
 	return rc;
 }

msm/dsi/dsi_panel.h

@@ -195,6 +195,8 @@ struct dsi_panel {
 	enum dsi_dms_mode dms_mode;
 
 	bool sync_broadcast_en;
+
+	int panel_test_gpio;
 };
 
 static inline bool dsi_panel_ulps_feature_enabled(struct dsi_panel *panel)