[PATCH v16 14/22] drm/mediatek: add display merge async reset control

[Nancy.Lin <nancy.lin@mediatek.com>]

Add merge async reset control in mtk_merge_stop. Async hw doesn't do self
reset on each sof signal(start of frame), so need to reset the async to
clear the hw status for the next merge start.

Signed-off-by: Nancy.Lin <nancy.lin@mediatek.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_merge.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_merge.c b/drivers/gpu/drm/mediatek/mtk_disp_merge.c
index 9dca145cfb71..177473fa8160 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_merge.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_merge.c
@@ -8,6 +8,7 @@
 #include <linux/of_device.h>
 #include <linux/of_irq.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/soc/mediatek/mtk-cmdq.h>
 
 #include "mtk_drm_ddp_comp.h"
@@ -79,6 +80,9 @@ void mtk_merge_stop(struct device *dev)
 	struct mtk_disp_merge *priv = dev_get_drvdata(dev);
 
 	mtk_merge_stop_cmdq(dev, NULL);
+
+	if (priv->async_clk)
+		device_reset_optional(dev);
 }
 
 void mtk_merge_start_cmdq(struct device *dev, struct cmdq_pkt *cmdq_pkt)
-- 
2.18.0