Re: [PATCH v3 1/2] drm/mediatek: Add gamma correction
From: CK Hu
Date: Fri Jul 15 2016 - 05:13:04 EST
Hi, Bibby:
Some comments inline.
On Thu, 2016-07-07 at 15:37 +0800, Bibby Hsieh wrote:
> 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@xxxxxxxxxxxx>
> ---
> 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
It's better that the digits of register address of OD, COLOR, AAL, and
GAMMA are the same. Maybe you can align all to 4 digits.
> +
> +#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);
> +}
I think AAL is somewhat different from GAMMA and this patch include 3
modifications:
1. AAL basic config
2. GAMMA basic config
3. Add gamma function of AAL and GAMMA
So you should split this patch into 3 patches.
> +
> +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,