[PATCH v3 1/2] drm/mediatek: Add gamma correction

CK Hu ck.hu at mediatek.com
Fri Jul 15 09:11:48 UTC 2016


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 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

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,




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