Newer Gamma IP have got multiple LUT banks: support specifying the
size of the LUT banks and handle bank-switching before programming
the LUT in mtk_gamma_set_common() in preparation for adding support
for MT8195 and newer SoCs.

Suggested-by: Jason-JH.Lin <jason-jh....@mediatek.com>
[Angelo: Refactored original commit]
Signed-off-by: AngeloGioacchino Del Regno 
<angelogioacchino.delre...@collabora.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_gamma.c | 78 +++++++++++++++--------
 1 file changed, 51 insertions(+), 27 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c 
b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
index 62e1e50d2671..b374dfc610ae 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_gamma.c
@@ -25,6 +25,8 @@
 #define DISP_GAMMA_SIZE                                0x0030
 #define DISP_GAMMA_SIZE_HSIZE                          GENMASK(28, 16)
 #define DISP_GAMMA_SIZE_VSIZE                          GENMASK(12, 0)
+#define DISP_GAMMA_BANK                                0x0100
+#define DISP_GAMMA_BANK_BANK                           GENMASK(1, 0)
 #define DISP_GAMMA_LUT                         0x0700
 
 #define DISP_GAMMA_LUT_10BIT_R                 GENMASK(29, 20)
@@ -38,6 +40,7 @@
 struct mtk_disp_gamma_data {
        bool has_dither;
        bool lut_diff;
+       u16 lut_bank_size;
        u16 lut_size;
        u8 lut_bits;
 };
@@ -84,9 +87,10 @@ void mtk_gamma_set_common(struct device *dev, void __iomem 
*regs, struct drm_crt
        struct drm_color_lut *lut;
        void __iomem *lut_base;
        bool lut_diff;
-       u16 lut_size;
+       u16 lut_bank_size, lut_size;
        u8 lut_bits;
-       u32 cfg_val, word;
+       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)
@@ -94,43 +98,61 @@ 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_bank_size = gamma->data->lut_bank_size;
                lut_bits = gamma->data->lut_bits;
                lut_size = gamma->data->lut_size;
        } else {
                lut_diff = false;
+               lut_bank_size = LUT_SIZE_DEFAULT;
                lut_bits = LUT_BITS_DEFAULT;
                lut_size = LUT_SIZE_DEFAULT;
        }
 
+       if (lut_bank_size)
+               num_lut_banks = lut_size / lut_bank_size;
+       else
+               num_lut_banks = 1;
+
        cfg_val = readl(regs + DISP_GAMMA_CFG);
        lut_base = regs + DISP_GAMMA_LUT;
        lut = (struct drm_color_lut *)state->gamma_lut->data;
-       for (i = 0; i < lut_size; i++) {
-               struct drm_color_lut diff, hwlut;
-
-               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);
-                       word |= FIELD_PREP(DISP_GAMMA_LUT_10BIT_G, hwlut.green);
-                       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);
-
-                       diff.green = lut[i].green - lut[i - 1].green;
-                       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);
-
-                       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);
+
+       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);
+                       writel(lbank_val, regs + DISP_GAMMA_BANK);
+               }
+
+               for (i = 0; i < lut_bank_size; i++) {
+                       int n = (cur_bank * lut_bank_size) + i;
+                       struct drm_color_lut diff, hwlut;
+
+                       hwlut.red = drm_color_lut_extract(lut[n].red, lut_bits);
+                       hwlut.green = drm_color_lut_extract(lut[n].green, 
lut_bits);
+                       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);
+                       } else {
+                               diff.red = lut[n].red - lut[n - 1].red;
+                               diff.red = drm_color_lut_extract(diff.red, 
lut_bits);
+
+                               diff.green = lut[n].green - lut[n - 1].green;
+                               diff.green = drm_color_lut_extract(diff.green, 
lut_bits);
+
+                               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);
+                       }
+                       writel(word, (lut_base + i * 4));
                }
-               writel(word, (lut_base + i * 4));
        }
 
        /* Enable the gamma table */
@@ -241,11 +263,13 @@ 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_bank_size = 256,
        .lut_bits = 10,
        .lut_size = 512,
 };
 
 static const struct mtk_disp_gamma_data mt8183_gamma_driver_data = {
+       .lut_bank_size = 256,
        .lut_bits = 10,
        .lut_diff = true,
        .lut_size = 512,
-- 
2.40.1

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