[PATCH v14 6/9] drm/msm/dpu: Use fixed DRM DSC helper for det_thresh_flatness

[Jessica Zhang <quic_jesszhan@quicinc.com>]

The current dpu_hw_dsc calculation for det_thresh_flatness does not
match the downstream calculation or the DSC spec.

Use the DRM DSC helper for det_thresh_flatness to match downstream
implementation and the DSC spec.

Fixes: c110cfd1753e ("drm/msm/disp/dpu1: Add support for DSC")
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Marijn Suijten <marijn.suijten@somainline.org>
Signed-off-by: Jessica Zhang <quic_jesszhan@quicinc.com>
---
 drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c
index 4e1396575e6a..3cad6a80af97 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_hw_dsc.c
@@ -3,6 +3,8 @@
  * Copyright (c) 2020-2022, Linaro Limited
  */
 
+#include <drm/display/drm_dsc_helper.h>
+
 #include "dpu_kms.h"
 #include "dpu_hw_catalog.h"
 #include "dpu_hwio.h"
@@ -102,7 +104,7 @@ static void dpu_hw_dsc_config(struct dpu_hw_dsc *hw_dsc,
 	data |= dsc->final_offset;
 	DPU_REG_WRITE(c, DSC_DSC_OFFSET, data);
 
-	det_thresh_flatness = 7 + 2 * (dsc->bits_per_component - 8);
+	det_thresh_flatness = drm_dsc_flatness_det_thresh(dsc);
 	data = det_thresh_flatness << 10;
 	data |= dsc->flatness_max_qp << 5;
 	data |= dsc->flatness_min_qp;

-- 
2.40.1