Re: [PATCH v4 2/4] drm/komeda: Add drm_lut_to_fgamma_coeffs()

[Brian Starkey]

Hi James,

On Tue, Oct 15, 2019 at 02:10:53AM +0000, james qian wang (Arm Technology China) wrote:
> This function is used to convert drm 3dlut to komeda HW required 1d curve

This is a 1D LUT, not a 3D LUT

Cheers,
-Brian

> coeffs values.
> 
> Signed-off-by: james qian wang (Arm Technology China) <james.qian.wang@xxxxxxx>
> Reviewed-by: Mihail Atanassov <mihail.atanassov@xxxxxxx>
> ---
>  .../arm/display/komeda/komeda_color_mgmt.c    | 52 +++++++++++++++++++
>  .../arm/display/komeda/komeda_color_mgmt.h    |  9 +++-
>  2 files changed, 60 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c
> index 9d14a92dbb17..c180ce70c26c 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.c
> @@ -65,3 +65,55 @@ const s32 *komeda_select_yuv2rgb_coeffs(u32 color_encoding, u32 color_range)
>  
>  	return coeffs;
>  }
> +
> +struct gamma_curve_sector {
> +	u32 boundary_start;
> +	u32 num_of_segments;
> +	u32 segment_width;
> +};
> +
> +struct gamma_curve_segment {
> +	u32 start;
> +	u32 end;
> +};
> +
> +static struct gamma_curve_sector sector_tbl[] = {
> +	{ 0,    4,  4   },
> +	{ 16,   4,  4   },
> +	{ 32,   4,  8   },
> +	{ 64,   4,  16  },
> +	{ 128,  4,  32  },
> +	{ 256,  4,  64  },
> +	{ 512,  16, 32  },
> +	{ 1024, 24, 128 },
> +};
> +
> +static void
> +drm_lut_to_coeffs(struct drm_property_blob *lut_blob, u32 *coeffs,
> +		  struct gamma_curve_sector *sector_tbl, u32 num_sectors)
> +{
> +	struct drm_color_lut *lut;
> +	u32 i, j, in, num = 0;
> +
> +	if (!lut_blob)
> +		return;
> +
> +	lut = lut_blob->data;
> +
> +	for (i = 0; i < num_sectors; i++) {
> +		for (j = 0; j < sector_tbl[i].num_of_segments; j++) {
> +			in = sector_tbl[i].boundary_start +
> +			     j * sector_tbl[i].segment_width;
> +
> +			coeffs[num++] = drm_color_lut_extract(lut[in].red,
> +						KOMEDA_COLOR_PRECISION);
> +		}
> +	}
> +
> +	coeffs[num] = BIT(KOMEDA_COLOR_PRECISION);
> +}
> +
> +void drm_lut_to_fgamma_coeffs(struct drm_property_blob *lut_blob, u32 *coeffs)
> +{
> +	drm_lut_to_coeffs(lut_blob, coeffs, sector_tbl, ARRAY_SIZE(sector_tbl));
> +}
> diff --git a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h
> index a2df218f58e7..08ab69281648 100644
> --- a/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h
> +++ b/drivers/gpu/drm/arm/display/komeda/komeda_color_mgmt.h
> @@ -11,7 +11,14 @@
>  #include <drm/drm_color_mgmt.h>
>  
>  #define KOMEDA_N_YUV2RGB_COEFFS		12
> +#define KOMEDA_N_RGB2YUV_COEFFS		12
> +#define KOMEDA_COLOR_PRECISION		12
> +#define KOMEDA_N_GAMMA_COEFFS		65
> +#define KOMEDA_COLOR_LUT_SIZE		BIT(KOMEDA_COLOR_PRECISION)
> +#define KOMEDA_N_CTM_COEFFS		9
> +
> +void drm_lut_to_fgamma_coeffs(struct drm_property_blob *lut_blob, u32 *coeffs);
>  
>  const s32 *komeda_select_yuv2rgb_coeffs(u32 color_encoding, u32 color_range);
>  
> -#endif
> +#endif /*_KOMEDA_COLOR_MGMT_H_*/
> -- 
> 2.20.1
>