drm/i915/icl: Power down DSI panel

This patch sends command and executes display off,
assert reset, power off VBT seqeuences to power
down DSI panel. Patch also adds high level function
to wrap all the panel sepcific programming during
DSI disabling.
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/efdafbf6b4d31123738b87b2d8264a9b5553eb32.1540900289.git.jani.nikula@intel.com

drivers/gpu/drm/i915/icl_dsi.c

@@ -800,6 +800,18 @@ static void gen11_dsi_disable_transcoder(struct intel_encoder *encoder)
 	}
 }
 
+static void gen11_dsi_powerdown_panel(struct intel_encoder *encoder)
+{
+	struct intel_dsi *intel_dsi = enc_to_intel_dsi(&encoder->base);
+
+	intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_DISPLAY_OFF);
+	intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_ASSERT_RESET);
+	intel_dsi_vbt_exec_sequence(intel_dsi, MIPI_SEQ_POWER_OFF);
+
+	/* ensure cmds dispatched to panel */
+	wait_for_cmds_dispatched_to_panel(encoder);
+}
+
 static void __attribute__((unused)) gen11_dsi_disable(
 			struct intel_encoder *encoder,
 			const struct intel_crtc_state *old_crtc_state,
@@ -813,4 +825,7 @@ static void __attribute__((unused)) gen11_dsi_disable(
 
 	/* step2d,e: disable transcoder and wait */
 	gen11_dsi_disable_transcoder(encoder);
+
+	/* step2f,g: powerdown panel */
+	gen11_dsi_powerdown_panel(encoder);
 }