Re: [PATCH v10 11/16] drm/mediatek: gamma: Add support for 12-bit LUT and MT8195

[CK Hu (胡俊光)]

Hi, Angelo:

On Fri, 2023-08-04 at 09:28 +0200, AngeloGioacchino Del Regno wrote:
> Add support for 12-bit gamma lookup tables and introduce the first
> user for it: MT8195.
> While at it, also reorder the variables in mtk_gamma_set_common()
> and rename `lut_base` to `lut0_base` to improve readability.

Separate 12-bit gamma support and mt8195 support to different patches.

Regards,
CK

> 
> Signed-off-by: AngeloGioacchino Del Regno <
> angelogioacchino.delregno@xxxxxxxxxxxxx>
> Reviewed-by: Jason-JH.Lin <jason-jh.lin@xxxxxxxxxxxx>
> Reviewed-by: Alexandre Mergnat <amergnat@xxxxxxxxxxxx>
> ---
>  drivers/gpu/drm/mediatek/mtk_disp_gamma.c | 74 +++++++++++++++++++
> ----
>  1 file changed, 62 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> index 3f1c6815ea5a..7d2f8042ace0 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> @@ -26,12 +26,20 @@
>  #define DISP_GAMMA_SIZE_VSIZE				GENMASK
> (12, 0)
>  #define DISP_GAMMA_BANK				0x0100
>  #define DISP_GAMMA_BANK_BANK				GENMASK(1, 0)
> +#define DISP_GAMMA_BANK_DATA_MODE			BIT(2)
>  #define DISP_GAMMA_LUT				0x0700
> +#define DISP_GAMMA_LUT1				0x0b00
>  
> +/* For 10 bit LUT layout, R/G/B are in the same register */
>  #define DISP_GAMMA_LUT_10BIT_R			GENMASK(29, 20)
>  #define DISP_GAMMA_LUT_10BIT_G			GENMASK(19, 10)
>  #define DISP_GAMMA_LUT_10BIT_B			GENMASK(9, 0)
>  
> +/* For 12 bit LUT layout, R/G are in LUT, B is in LUT1 */
> +#define DISP_GAMMA_LUT_12BIT_R			GENMASK(11, 0)
> +#define DISP_GAMMA_LUT_12BIT_G			GENMASK(23, 12)
> +#define DISP_GAMMA_LUT_12BIT_B			GENMASK(11, 0)
> +
>  #define LUT_10BIT_MASK				0x03ff
>  #define LUT_BITS_DEFAULT			10
>  #define LUT_SIZE_DEFAULT			512
> @@ -77,14 +85,30 @@ unsigned int mtk_gamma_get_lut_size(struct device
> *dev)
>  	return LUT_SIZE_DEFAULT;
>  }
>  
> +/*
> + * SoCs supporting 12-bits LUTs are using a new register layout that
> does
> + * always support (by HW) both 12-bits and 10-bits LUT but, on
> those, we
> + * ignore the support for 10-bits in this driver and always use 12-
> bits.
> + *
> + * Summarizing:
> + * - SoC HW support 9/10-bits LUT only
> + *   - Old register layout
> + *     - 10-bits LUT supported
> + *     - 9-bits LUT not supported
> + * - SoC HW support both 10/12bits LUT
> + *   - New register layout
> + *     - 12-bits LUT supported
> + *     - 10-its LUT not supported
> + */
>  void mtk_gamma_set(struct device *dev, struct drm_crtc_state *state)
>  {
>  	struct mtk_disp_gamma *gamma = dev_get_drvdata(dev);
> -	unsigned int i;
> -	struct drm_color_lut *lut;
> -	void __iomem *lut_base;
> -	u32 cfg_val, lbank_val, word;
> +	void __iomem *lut0_base = gamma->regs + DISP_GAMMA_LUT;
> +	void __iomem *lut1_base = gamma->regs + DISP_GAMMA_LUT1;
> +	u32 cfg_val, data_mode, lbank_val, word[2];
>  	int cur_bank, num_lut_banks;
> +	struct drm_color_lut *lut;
> +	unsigned int i;
>  
>  	/* If there's no gamma lut there's nothing to do here. */
>  	if (!state->gamma_lut)
> @@ -92,14 +116,17 @@ void mtk_gamma_set(struct device *dev, struct
> drm_crtc_state *state)
>  
>  	num_lut_banks = gamma->data->lut_size / gamma->data-
> >lut_bank_size;
>  	cfg_val = readl(gamma->regs + DISP_GAMMA_CFG);
> -	lut_base = gamma->regs + DISP_GAMMA_LUT;
>  	lut = (struct drm_color_lut *)state->gamma_lut->data;
>  
> +	/* Switch to 12 bits data mode if supported */
> +	data_mode = FIELD_PREP(DISP_GAMMA_BANK_DATA_MODE, !!(gamma-
> >data->lut_bits == 12));
> +
>  	for (cur_bank = 0; cur_bank < num_lut_banks; cur_bank++) {
>  
>  		/* Switch gamma bank and set data mode before writing
> LUT */
>  		if (num_lut_banks > 1) {
>  			lbank_val = FIELD_PREP(DISP_GAMMA_BANK_BANK,
> cur_bank);
> +			lbank_val |= data_mode;
>  			writel(lbank_val, gamma->regs +
> DISP_GAMMA_BANK);
>  		}
>  
> @@ -112,9 +139,15 @@ void mtk_gamma_set(struct device *dev, struct
> drm_crtc_state *state)
>  			hwlut.blue = drm_color_lut_extract(lut[n].blue,
> gamma->data->lut_bits);
>  
>  			if (!gamma->data->lut_diff || (i % 2 == 0)) {
> -				word =
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_R, hwlut.red);
> -				word |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_G, hwlut.green);
> -				word |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_B, hwlut.blue);
> +				if (gamma->data->lut_bits == 12) {
> +					word[0] =
> FIELD_PREP(DISP_GAMMA_LUT_12BIT_R, hwlut.red);
> +					word[0] |=
> FIELD_PREP(DISP_GAMMA_LUT_12BIT_G, hwlut.green);
> +					word[1] =
> FIELD_PREP(DISP_GAMMA_LUT_12BIT_B, hwlut.blue);
> +				} else {
> +					word[0] =
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_R, hwlut.red);
> +					word[0] |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_G, hwlut.green);
> +					word[0] |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_B, hwlut.blue);
> +				}
>  			} else {
>  				diff.red = lut[n].red - lut[n - 1].red;
>  				diff.red =
> drm_color_lut_extract(diff.red, gamma->data->lut_bits);
> @@ -125,11 +158,19 @@ void mtk_gamma_set(struct device *dev, struct
> drm_crtc_state *state)
>  				diff.blue = lut[n].blue - lut[n -
> 1].blue;
>  				diff.blue =
> drm_color_lut_extract(diff.blue, gamma->data->lut_bits);
>  
> -				word =
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_R, diff.red);
> -				word |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_G, diff.green);
> -				word |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_B, diff.blue);
> +				if (gamma->data->lut_bits == 12) {
> +					word[0] =
> FIELD_PREP(DISP_GAMMA_LUT_12BIT_R, diff.red);
> +					word[0] |=
> FIELD_PREP(DISP_GAMMA_LUT_12BIT_G, diff.green);
> +					word[1] =
> FIELD_PREP(DISP_GAMMA_LUT_12BIT_B, diff.blue);
> +				} else {
> +					word[0] =
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_R, diff.red);
> +					word[0] |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_G, diff.green);
> +					word[0] |=
> FIELD_PREP(DISP_GAMMA_LUT_10BIT_B, diff.blue);
> +				}
>  			}
> -			writel(word, (lut_base + i * 4));
> +			writel(word[0], (lut0_base + i * 4));
> +			if (gamma->data->lut_bits == 12)
> +				writel(word[1], (lut1_base + i * 4));
>  		}
>  	}
>  
> @@ -246,11 +287,20 @@ static const struct mtk_disp_gamma_data
> mt8183_gamma_driver_data = {
>  	.lut_size = 512,
>  };
>  
> +static const struct mtk_disp_gamma_data mt8195_gamma_driver_data = {
> +	.lut_bank_size = 256,
> +	.lut_bits = 12,
> +	.lut_diff = true,
> +	.lut_size = 1024,
> +};
> +
>  static const struct of_device_id mtk_disp_gamma_driver_dt_match[] =
> {
>  	{ .compatible = "mediatek,mt8173-disp-gamma",
>  	  .data = &mt8173_gamma_driver_data},
>  	{ .compatible = "mediatek,mt8183-disp-gamma",
>  	  .data = &mt8183_gamma_driver_data},
> +	{ .compatible = "mediatek,mt8195-disp-gamma",
> +	  .data = &mt8195_gamma_driver_data},
>  	{},
>  };
>  MODULE_DEVICE_TABLE(of, mtk_disp_gamma_driver_dt_match);