[PATCH] drm/mediatek: Add support for 180-degree rotation in the display driver

[Jason-JH.Lin]

mediatek-drm driver reported the capability of 180-degree rotation by
adding `DRM_MODE_ROTATE_180` to the plane property, as flip-x combined
with flip-y equals a 180-degree rotation. However, we did not handle
the rotation property in the driver and lead to rotation issues.

Fixes: 74608d8feefd ("drm/mediatek: Add DRM_MODE_ROTATE_0 to rotation property")
Signed-off-by: Jason-JH.Lin <jason-jh.lin at mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_ovl.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
index e0c0bb01f65a..cc825c4f2e09 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl.c
@@ -472,6 +472,7 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
 	unsigned int hdr_pitch = pending->hdr_pitch;
 	unsigned int fmt = pending->format;
 	unsigned int offset = (pending->y << 16) | pending->x;
+	unsigned int rotation = pending->rotation;
 	unsigned int src_size = (pending->height << 16) | pending->width;
 	unsigned int blend_mode = state->base.pixel_blend_mode;
 	unsigned int ignore_pixel_alpha = 0;
@@ -513,12 +514,19 @@ void mtk_ovl_layer_config(struct device *dev, unsigned int idx,
 			ignore_pixel_alpha = OVL_CONST_BLEND;
 	}
 
-	if (pending->rotation & DRM_MODE_REFLECT_Y) {
+	/*
+	 * Treat rotate 180 as flip x + flip y, and XOR the original rotation value
+	 * to flip x + flip y to support both in the same time.
+	 */
+	if (rotation & DRM_MODE_ROTATE_180)
+		rotation ^= DRM_MODE_REFLECT_X | DRM_MODE_REFLECT_Y;
+
+	if (rotation & DRM_MODE_REFLECT_Y) {
 		con |= OVL_CON_VIRT_FLIP;
 		addr += (pending->height - 1) * pending->pitch;
 	}
 
-	if (pending->rotation & DRM_MODE_REFLECT_X) {
+	if (rotation & DRM_MODE_REFLECT_X) {
 		con |= OVL_CON_HORZ_FLIP;
 		addr += pending->pitch - 1;
 	}
-- 
2.43.0