[PATCH AUTOSEL for 4.9 20/50] drm: mali-dp: fix Lx_CONTROL register fields clobber

[Levin, Alexander (Sasha Levin)]

From: Mihail Atanassov <mihail.atanassov@xxxxxxx>

[ Upstream commit c7ffa59cf03c38b91d6ef01e42c1b52fd7a4f285 ]

When updating the rotation fields, one of the assignments zeroes out the
rest of the register fields, which include settings for chroma siting,
inverse gamma, AMBA AXI caching, and alpha blending.

Signed-off-by: Mihail Atanassov <mihail.atanassov@xxxxxxx>
Signed-off-by: Liviu Dudau <Liviu.Dudau@xxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx>
---
 drivers/gpu/drm/arm/malidp_planes.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/arm/malidp_planes.c b/drivers/gpu/drm/arm/malidp_planes.c
index afe0480d95c9..8b009b549e45 100644
--- a/drivers/gpu/drm/arm/malidp_planes.c
+++ b/drivers/gpu/drm/arm/malidp_planes.c
@@ -182,7 +182,8 @@ static void malidp_de_plane_update(struct drm_plane *plane,
 
 	/* setup the rotation and axis flip bits */
 	if (plane->state->rotation & DRM_ROTATE_MASK)
-		val = ilog2(plane->state->rotation & DRM_ROTATE_MASK) << LAYER_ROT_OFFSET;
+		val |= ilog2(plane->state->rotation & DRM_ROTATE_MASK) <<
+		       LAYER_ROT_OFFSET;
 	if (plane->state->rotation & DRM_REFLECT_X)
 		val |= LAYER_H_FLIP;
 	if (plane->state->rotation & DRM_REFLECT_Y)
-- 
2.11.0