[PATCH v3 07/11] drm/mediatek: gamma: Support specifying number of bits per LUT component

[AngeloGioacchino Del Regno]

New SoCs, like MT8195, not only may support bigger lookup tables, but
have got a different register layout to support bigger precision:
support specifying the number of `lut_bits` for each SoC and use it
in mtk_gamma_set_common() to perform the right calculation.

Signed-off-by: AngeloGioacchino Del Regno 
<angelogioacchino.delre...@collabora.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_gamma.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c 
b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
index ed2aa1fb0171..62e1e50d2671 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
@@ -39,6 +39,7 @@ struct mtk_disp_gamma_data {
        bool has_dither;
        bool lut_diff;
        u16 lut_size;
+       u8 lut_bits;
 };
 
 /*
@@ -84,6 +85,7 @@ void mtk_gamma_set_common(struct device *dev, void __iomem 
*regs, struct drm_crt
        void __iomem *lut_base;
        bool lut_diff;
        u16 lut_size;
+       u8 lut_bits;
        u32 cfg_val, word;
 
        /* If there's no gamma lut there's nothing to do here. */
@@ -92,9 +94,11 @@ void mtk_gamma_set_common(struct device *dev, void __iomem 
*regs, struct drm_crt
 
        if (gamma && gamma->data) {
                lut_diff = gamma->data->lut_diff;
+               lut_bits = gamma->data->lut_bits;
                lut_size = gamma->data->lut_size;
        } else {
                lut_diff = false;
+               lut_bits = LUT_BITS_DEFAULT;
                lut_size = LUT_SIZE_DEFAULT;
        }
 
@@ -104,9 +108,9 @@ void mtk_gamma_set_common(struct device *dev, void __iomem 
*regs, struct drm_crt
        for (i = 0; i < lut_size; i++) {
                struct drm_color_lut diff, hwlut;
 
-               hwlut.red = drm_color_lut_extract(lut[i].red, LUT_BITS_DEFAULT);
-               hwlut.green = drm_color_lut_extract(lut[i].green, 
LUT_BITS_DEFAULT);
-               hwlut.blue = drm_color_lut_extract(lut[i].blue, 
LUT_BITS_DEFAULT);
+               hwlut.red = drm_color_lut_extract(lut[i].red, lut_bits);
+               hwlut.green = drm_color_lut_extract(lut[i].green, lut_bits);
+               hwlut.blue = drm_color_lut_extract(lut[i].blue, lut_bits);
 
                if (!lut_diff || (i % 2 == 0)) {
                        word = FIELD_PREP(DISP_GAMMA_LUT_10BIT_R, hwlut.red);
@@ -114,13 +118,13 @@ void mtk_gamma_set_common(struct device *dev, void 
__iomem *regs, struct drm_crt
                        word |= FIELD_PREP(DISP_GAMMA_LUT_10BIT_B, hwlut.blue);
                } else {
                        diff.red = lut[i].red - lut[i - 1].red;
-                       diff.red = drm_color_lut_extract(diff.red, 
LUT_BITS_DEFAULT);
+                       diff.red = drm_color_lut_extract(diff.red, lut_bits);
 
                        diff.green = lut[i].green - lut[i - 1].green;
-                       diff.green = drm_color_lut_extract(diff.green, 
LUT_BITS_DEFAULT);
+                       diff.green = drm_color_lut_extract(diff.green, 
lut_bits);
 
                        diff.blue = lut[i].blue - lut[i - 1].blue;
-                       diff.blue = drm_color_lut_extract(diff.blue, 
LUT_BITS_DEFAULT);
+                       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);
@@ -237,10 +241,12 @@ static int mtk_disp_gamma_remove(struct platform_device 
*pdev)
 
 static const struct mtk_disp_gamma_data mt8173_gamma_driver_data = {
        .has_dither = true,
+       .lut_bits = 10,
        .lut_size = 512,
 };
 
 static const struct mtk_disp_gamma_data mt8183_gamma_driver_data = {
+       .lut_bits = 10,
        .lut_diff = true,
        .lut_size = 512,
 };
-- 
2.40.1