[PATCH] drm/rockchip: vop2: fix suspend/resume

[Sascha Hauer]

During a suspend/resume cycle the VO power domain will be disabled and
the VOP2 registers will reset to their default values. After that the
cached register values will be out of sync and the read/modify/write
operations we do on the window registers will result in bogus values
written. Fix this by marking the regcache as dirty each time we disable
the VOP2 and call regcache_sync() each time we enable it again. With
this the VOP2 will show a picture after a suspend/resume cycle whereas
without this the screen stays dark.

Fixes: 604be85547ce4 ("drm/rockchip: Add VOP2 driver")
Cc: stable at vger.kernel.org
Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---

Changes since v1:
- Use regcache_mark_dirty()/regcache_sync() instead of regmap_reinit_cache()

 drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
index ba3b817895091..293c228a83f90 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
@@ -839,6 +839,8 @@ static void vop2_enable(struct vop2 *vop2)
 		return;
 	}
 
+	regcache_sync(vop2->map);
+
 	if (vop2->data->soc_id == 3566)
 		vop2_writel(vop2, RK3568_OTP_WIN_EN, 1);
 
@@ -867,6 +869,8 @@ static void vop2_disable(struct vop2 *vop2)
 
 	pm_runtime_put_sync(vop2->dev);
 
+	regcache_mark_dirty(vop2->map);
+
 	clk_disable_unprepare(vop2->aclk);
 	clk_disable_unprepare(vop2->hclk);
 }
-- 
2.39.2