Re: [PATCH RESEND v6 09/11] drm/mediatek: gamma: Add support for 12-bit LUT and MT8195

Alexandre Mergnat
2023-07-27T11:04:11Z

Hi Angelo !

On 27/07/2023 11:46, 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.
>
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> Reviewed-by: Jason-JH.Lin <jason-jh.lin@mediatek.com>
> ---
> drivers/gpu/drm/mediatek/mtk_disp_gamma.c | 61 ++++++++++++++++++-----
> 1 file changed, 48 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> index f1a0b18b6c1a..e0e2d2bdbf59 100644
> --- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> +++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
> @@ -27,12 +27,20 @@
> #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

Is this offset generic to all MTK SoC which support this driver ?

>
> +/* 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 */

As I understood from the application processor registers (v0.4), R/G are
in LUT, B is in LUT1 for 10bit and 12bit for MT8195. Can you check
please to be sure ?

> +#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
> @@ -83,14 +91,15 @@ unsigned int mtk_gamma_get_lut_size(struct device *dev)
> void mtk_gamma_set_common(struct device *dev, void __iomem *regs, struct drm_crtc_state *state)
> {
> struct mtk_disp_gamma *gamma = dev_get_drvdata(dev);
> - unsigned int i;
> + void __iomem *lut0_base = regs + DISP_GAMMA_LUT;
> + void __iomem *lut1_base = regs + DISP_GAMMA_LUT1;
> + u32 cfg_val, data_mode, lbank_val, word[2];
> + int cur_bank, num_lut_banks;
> + u16 lut_bank_size, lut_size;
> struct drm_color_lut *lut;
> - void __iomem *lut_base;
> + unsigned int i;
> bool lut_diff;
> - u16 lut_bank_size, lut_size;
> u8 lut_bits;
> - u32 cfg_val, lbank_val, word;
> - int cur_bank, num_lut_banks;
>
> /* If there's no gamma lut there's nothing to do here. */
> if (!state->gamma_lut)
> @@ -110,14 +119,17 @@ void mtk_gamma_set_common(struct device *dev, void __iomem *regs, struct drm_crt
> num_lut_banks = lut_size / lut_bank_size;
>
> cfg_val = readl(regs + DISP_GAMMA_CFG);
> - lut_base = 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, !!(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, regs + DISP_GAMMA_BANK);
> }
>
> @@ -130,9 +142,15 @@ void mtk_gamma_set_common(struct device *dev, void __iomem *regs, struct drm_crt
> hwlut.blue = drm_color_lut_extract(lut[n].blue, lut_bits);
>
> if (!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 (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, lut_bits);
> @@ -143,11 +161,19 @@ void mtk_gamma_set_common(struct device *dev, void __iomem *regs, struct drm_crt
> diff.blue = lut[n].blue - lut[n - 1].blue;
> diff.blue = drm_color_lut_extract(diff.blue, 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 (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 (lut_bits == 12)
> + writel(word[1], (lut1_base + i * 4));

ditto

> }
> }
>
> @@ -271,11 +297,20 @@ 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,

If I'm right, ".lut_bits = 10" will not work properly.

> + .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);

--
Regards,
Alexandre