Re: [PATCH v4 6/8] drm/mediatek: add matrix bits private data for ccorr

CK Hu
2021-01-29T08:50:00Z

Hi, Hsin-Yi:

On Fri, 2021-01-29 at 15:34 +0800, Hsin-Yi Wang wrote:
> From: Yongqiang Niu <yongqiang.niu@mediatek.com>
>
> matrix bits of mt8183 is 12
> matrix bits of mt8192 is 13
>
> Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
> Signed-off-by: Hsin-Yi Wang <hsinyi@chromium.org>
> ---
> drivers/gpu/drm/mediatek/mtk_disp_ccorr.c | 22 +++++++++++++++++++---
> 1 file changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ccorr.c b/drivers/gpu/drm/mediatek/mtk_disp_ccorr.c
> index 0c68090eb1e92..1c7163a12f3b1 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_ccorr.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_ccorr.c
> @@ -31,8 +31,10 @@
> #define DISP_CCORR_COEF_3 0x008C
> #define DISP_CCORR_COEF_4 0x0090
>
> +#define CCORR_MATRIX_BITS 12
> +
> struct mtk_disp_ccorr_data {
> - u32 reserved;
> + u32 matrix_bits;
> };
>
> /**
> @@ -116,6 +118,7 @@ void mtk_ccorr_ctm_set(struct device *dev, struct drm_crtc_state *state)
> uint16_t coeffs[9] = { 0 };
> int i;
> struct cmdq_pkt *cmdq_pkt = NULL;
> + u32 matrix_bits;
>
> if (!blob)
> return;
> @@ -123,8 +126,16 @@ void mtk_ccorr_ctm_set(struct device *dev, struct drm_crtc_state *state)
> ctm = (struct drm_color_ctm *)blob->data;
> input = ctm->matrix;
>
> - for (i = 0; i < ARRAY_SIZE(coeffs); i++)
> + if (ccorr->data)
> + matrix_bits = ccorr->data->matrix_bits;
> + else
> + matrix_bits = CCORR_MATRIX_BITS;
> +
> + for (i = 0; i < ARRAY_SIZE(coeffs); i++) {
> coeffs[i] = mtk_ctm_s31_32_to_s1_10(input[i]);
> + if (matrix_bits > CCORR_MATRIX_BITS)
> + coeffs[i] <<= (matrix_bits - CCORR_MATRIX_BITS);

I think format of MT8192 ccorr coeffs is s1.11, after
mtk_ctm_s31_32_to_s1_10(), you lose one bit precision. So modify
mtk_ctm_s31_32_to_s1_10() to get maximum precision.

Regards,
CK

> + }
>
> mtk_ddp_write(cmdq_pkt, coeffs[0] << 16 | coeffs[1],
> &ccorr->cmdq_reg, ccorr->regs, DISP_CCORR_COEF_0);
> @@ -205,8 +216,13 @@ static int mtk_disp_ccorr_remove(struct platform_device *pdev)
> return 0;
> }
>
> +static const struct mtk_disp_ccorr_data mt8183_ccorr_driver_data = {
> + .matrix_bits = CCORR_MATRIX_BITS,
> +};
> +
> static const struct of_device_id mtk_disp_ccorr_driver_dt_match[] = {
> - { .compatible = "mediatek,mt8183-disp-ccorr"},
> + { .compatible = "mediatek,mt8183-disp-ccorr",
> + .data = &mt8183_ccorr_driver_data},
> {},
> };
> MODULE_DEVICE_TABLE(of, mtk_disp_ccorr_driver_dt_match);