drm/i915/icl: Disable portsync mode

This patch disables portsync mode if DSI link
is operating in dual link mode by writing to
TRANS_DDI_FUNC_CTL2 registers.
Signed-off-by: Madhav Chauhan <madhav.chauhan@intel.com>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/3e608420b58930b6da478801bff018c6e964eb94.1540900289.git.jani.nikula@intel.com

drivers/gpu/drm/i915/icl_dsi.c

@@ -841,6 +841,16 @@ static void gen11_dsi_deconfigure_trancoder(struct intel_encoder *encoder)
 		tmp &= ~TRANS_DDI_FUNC_ENABLE;
 		I915_WRITE(TRANS_DDI_FUNC_CTL(dsi_trans), tmp);
 	}
+
+	/* disable port sync mode if dual link */
+	if (intel_dsi->dual_link) {
+		for_each_dsi_port(port, intel_dsi->ports) {
+			dsi_trans = dsi_port_to_transcoder(port);
+			tmp = I915_READ(TRANS_DDI_FUNC_CTL2(dsi_trans));
+			tmp &= ~PORT_SYNC_MODE_ENABLE;
+			I915_WRITE(TRANS_DDI_FUNC_CTL2(dsi_trans), tmp);
+		}
+	}
 }
 
 static void __attribute__((unused)) gen11_dsi_disable(