drm/mediatek: Add gamma correction.

Add gamma set function to correct brightness values.
It applies arbitrary mapping curve to compensate the
incorrect transfer function of the panel.

Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>

1 files changed, 6 insertions, 1 deletions

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index 24aa3bad1e76..e3ac2802e024 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -409,6 +409,9 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
         }
         if (pending_planes)
                 mtk_crtc->pending_planes = true;
+        if (crtc->state->color_mgmt_changed)
+                for (i = 0; i < mtk_crtc->ddp_comp_nr; i++)
+                        mtk_ddp_gamma_set(mtk_crtc->ddp_comp[i], crtc->state);
 }
 
 static const struct drm_crtc_funcs mtk_crtc_funcs = {
@@ -418,6 +421,7 @@ static const struct drm_crtc_funcs mtk_crtc_funcs = {
         .reset                  = mtk_drm_crtc_reset,
         .atomic_duplicate_state = mtk_drm_crtc_duplicate_state,
         .atomic_destroy_state   = mtk_drm_crtc_destroy_state,
+        .gamma_set              = drm_atomic_helper_legacy_gamma_set,
 };
 
 static const struct drm_crtc_helper_funcs mtk_crtc_helper_funcs = {
@@ -568,7 +572,8 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
                                 &mtk_crtc->planes[1].base, pipe);
         if (ret < 0)
                 goto unprepare;
-
+        drm_mode_crtc_set_gamma_size(&mtk_crtc->base, MTK_LUT_SIZE);
+        drm_crtc_enable_color_mgmt(&mtk_crtc->base, 0, false, MTK_LUT_SIZE);
         priv->crtc[pipe] = &mtk_crtc->base;
         priv->num_pipes++;