Apply gamma 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 at mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c     |    8 +++
 drivers/gpu/drm/mediatek/mtk_drm_crtc.h     |    1 +
 drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c |   89 ++++++++++++++++++++++++++-
 drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h |   10 +++
 4 files changed, 106 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c 
b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index 24aa3ba..ee219bb 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -409,6 +409,10 @@ 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 +422,7 @@ 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 = {
@@ -569,6 +574,9 @@ int mtk_drm_crtc_create(struct drm_device *drm_dev,
        if (ret < 0)
                goto unprepare;

+       drm_mode_crtc_set_gamma_size(&mtk_crtc->base, MTK_LUT_SIZE);
+       drm_helper_crtc_enable_color_mgmt(&mtk_crtc->base, MTK_LUT_SIZE,
+                                         MTK_LUT_SIZE);
        priv->crtc[pipe] = &mtk_crtc->base;
        priv->num_pipes++;

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.h 
b/drivers/gpu/drm/mediatek/mtk_drm_crtc.h
index 81e5566..d332564 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.h
@@ -19,6 +19,7 @@
 #include "mtk_drm_plane.h"

 #define OVL_LAYER_NR   4
+#define MTK_LUT_SIZE   512

 int mtk_drm_crtc_enable_vblank(struct drm_device *drm, unsigned int pipe);
 void mtk_drm_crtc_disable_vblank(struct drm_device *drm, unsigned int pipe);
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c 
b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
index 3970fcf..56c5894 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.c
@@ -24,6 +24,7 @@
 #include "mtk_drm_drv.h"
 #include "mtk_drm_plane.h"
 #include "mtk_drm_ddp_comp.h"
+#include "mtk_drm_crtc.h"

 #define DISP_OD_EN                             0x0000
 #define DISP_OD_INTEN                          0x0008
@@ -38,6 +39,21 @@
 #define DISP_COLOR_WIDTH                       0x0c50
 #define DISP_COLOR_HEIGHT                      0x0c54

+#define DISP_AAL_EN                            0x000
+#define DISP_AAL_SIZE                          0x030
+
+#define DISP_GAMMA_EN                          0x000
+#define DISP_GAMMA_CFG                         0x020
+#define DISP_GAMMA_SIZE                                0x030
+#define DISP_GAMMA_LUT                         0x700
+
+#define LUT_10BIT_MASK                         0x3ff
+
+#define AAL_EN                 BIT(0)
+
+#define GAMMA_EN               BIT(0)
+#define GAMMA_LUT_EN           BIT(1)
+
 #define        OD_RELAY_MODE           BIT(0)

 #define        UFO_BYPASS              BIT(2)
@@ -76,6 +92,61 @@ static void mtk_ufoe_start(struct mtk_ddp_comp *comp)
        writel(UFO_BYPASS, comp->regs + DISP_REG_UFO_START);
 }

+static void mtk_aal_config(struct mtk_ddp_comp *comp, unsigned int w,
+                          unsigned int h, unsigned int vrefresh)
+{
+       writel(h << 16 | w, comp->regs + DISP_AAL_SIZE);
+}
+
+static void mtk_aal_start(struct mtk_ddp_comp *comp)
+{
+       writel(AAL_EN, comp->regs  + DISP_AAL_EN);
+}
+
+static void mtk_aal_stop(struct mtk_ddp_comp *comp)
+{
+       writel_relaxed(0x0, comp->regs  + DISP_AAL_EN);
+}
+
+static void mtk_gamma_config(struct mtk_ddp_comp *comp, unsigned int w,
+                            unsigned int h, unsigned int vrefresh)
+{
+       writel(h << 16 | w, comp->regs + DISP_GAMMA_SIZE);
+}
+
+static void mtk_gamma_start(struct mtk_ddp_comp *comp)
+{
+       writel(GAMMA_EN, comp->regs  + DISP_GAMMA_EN);
+}
+
+static void mtk_gamma_stop(struct mtk_ddp_comp *comp)
+{
+       writel_relaxed(0x0, comp->regs  + DISP_GAMMA_EN);
+}
+
+static void mtk_gamma_set(struct mtk_ddp_comp *comp,
+                         struct drm_crtc_state *state)
+{
+       unsigned int i, reg;
+       struct drm_color_lut *lut;
+       void __iomem *lut_base;
+       u32 word;
+
+       if (state->gamma_lut) {
+               reg = readl(comp->regs + DISP_GAMMA_CFG);
+               reg = reg | GAMMA_LUT_EN;
+               writel(reg, comp->regs + DISP_GAMMA_CFG);
+               lut_base = comp->regs + DISP_GAMMA_LUT;
+               lut = (struct drm_color_lut *)state->gamma_lut->data;
+               for (i = 0; i < MTK_LUT_SIZE; i++) {
+                       word = (((lut[i].red >> 6) & LUT_10BIT_MASK) << 20) +
+                             (((lut[i].green >> 6) & LUT_10BIT_MASK) << 10) +
+                             ((lut[i].blue >> 6) & LUT_10BIT_MASK);
+                       writel(word, (lut_base + i * 4));
+               }
+       }
+}
+
 static const struct mtk_ddp_comp_funcs ddp_color = {
        .config = mtk_color_config,
        .start = mtk_color_start,
@@ -90,6 +161,20 @@ static const struct mtk_ddp_comp_funcs ddp_ufoe = {
        .start = mtk_ufoe_start,
 };

+static const struct mtk_ddp_comp_funcs ddp_aal = {
+       .gamma_set = mtk_gamma_set,
+       .config = mtk_aal_config,
+       .start = mtk_aal_start,
+       .stop = mtk_aal_stop,
+};
+
+static const struct mtk_ddp_comp_funcs ddp_gamma = {
+       .gamma_set = mtk_gamma_set,
+       .config = mtk_gamma_config,
+       .start = mtk_gamma_start,
+       .stop = mtk_gamma_stop,
+};
+
 static const char * const mtk_ddp_comp_stem[MTK_DDP_COMP_TYPE_MAX] = {
        [MTK_DISP_OVL] = "ovl",
        [MTK_DISP_RDMA] = "rdma",
@@ -112,13 +197,13 @@ struct mtk_ddp_comp_match {
 };

 static const struct mtk_ddp_comp_match mtk_ddp_matches[DDP_COMPONENT_ID_MAX] = 
{
-       [DDP_COMPONENT_AAL]     = { MTK_DISP_AAL,       0, NULL },
+       [DDP_COMPONENT_AAL]     = { MTK_DISP_AAL,       0, &ddp_aal },
        [DDP_COMPONENT_COLOR0]  = { MTK_DISP_COLOR,     0, &ddp_color },
        [DDP_COMPONENT_COLOR1]  = { MTK_DISP_COLOR,     1, &ddp_color },
        [DDP_COMPONENT_DPI0]    = { MTK_DPI,            0, NULL },
        [DDP_COMPONENT_DSI0]    = { MTK_DSI,            0, NULL },
        [DDP_COMPONENT_DSI1]    = { MTK_DSI,            1, NULL },
-       [DDP_COMPONENT_GAMMA]   = { MTK_DISP_GAMMA,     0, NULL },
+       [DDP_COMPONENT_GAMMA]   = { MTK_DISP_GAMMA,     0, &ddp_gamma },
        [DDP_COMPONENT_OD]      = { MTK_DISP_OD,        0, &ddp_od },
        [DDP_COMPONENT_OVL0]    = { MTK_DISP_OVL,       0, NULL },
        [DDP_COMPONENT_OVL1]    = { MTK_DISP_OVL,       1, NULL },
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h 
b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
index 6b13ba9..07e17fe 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_ddp_comp.h
@@ -20,6 +20,7 @@ struct device;
 struct device_node;
 struct drm_crtc;
 struct drm_device;
+struct drm_crtc_state;
 struct mtk_plane_state;

 enum mtk_ddp_comp_type {
@@ -73,6 +74,8 @@ struct mtk_ddp_comp_funcs {
        void (*layer_off)(struct mtk_ddp_comp *comp, unsigned int idx);
        void (*layer_config)(struct mtk_ddp_comp *comp, unsigned int idx,
                             struct mtk_plane_state *state);
+       void (*gamma_set)(struct mtk_ddp_comp *comp,
+                         struct drm_crtc_state *state);
 };

 struct mtk_ddp_comp {
@@ -139,6 +142,13 @@ static inline void mtk_ddp_comp_layer_config(struct 
mtk_ddp_comp *comp,
                comp->funcs->layer_config(comp, idx, state);
 }

+static inline void mtk_ddp_gamma_set(struct mtk_ddp_comp *comp,
+                                    struct drm_crtc_state *state)
+{
+       if (comp->funcs && comp->funcs->gamma_set)
+               comp->funcs->gamma_set(comp, state);
+}
+
 int mtk_ddp_comp_get_id(struct device_node *node,
                        enum mtk_ddp_comp_type comp_type);
 int mtk_ddp_comp_init(struct device *dev, struct device_node *comp_node,
-- 
1.7.9.5

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