drm/mediatek: De-commonize disp_aal/disp_gamma gamma_set functions

In preparation for adding a 12-bits gamma support for the DISP_GAMMA
IP, remove the mtk_gamma_set_common() function and move the relevant
bits in mtk_gamma_set() for DISP_GAMMA and mtk_aal_gamma_set() for
DISP_AAL: since the latter has no more support for gamma manipulation
(being moved to a different IP) in newer revisions, those functions
are about to diverge and it makes no sense to keep a common one (with
all the complications of passing common data and making exclusions
for device driver data) for just a few bits.

This commit brings no functional changes.
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Reviewed-by: Nícolas F. R. A. Prado <nfraprado@collabora.com>
Reviewed-by: CK Hu <ck.hu@mediatek.com>
Link: https://patchwork.kernel.org/project/dri-devel/patch/20231012095736.100784-9-angelogioacchino.delregno@collabora.com/Signed-off-by: Chun-Kuang Hu <chunkuang.hu@kernel.org>

drivers/gpu/drm/mediatek/mtk_disp_gamma.c

@@ -69,41 +69,28 @@ unsigned int mtk_gamma_get_lut_size(struct device *dev)
 	return 0;
 }
 
-void mtk_gamma_set_common(struct device *dev, void __iomem *regs, struct drm_crtc_state *state)
+void mtk_gamma_set(struct device *dev, struct drm_crtc_state *state)
 {
-	struct mtk_disp_gamma *gamma;
+	struct mtk_disp_gamma *gamma = dev_get_drvdata(dev);
 	unsigned int i;
 	struct drm_color_lut *lut;
 	void __iomem *lut_base;
-	bool lut_diff;
-	u16 lut_size;
 	u32 cfg_val, word;
 
 	/* If there's no gamma lut there's nothing to do here. */
 	if (!state->gamma_lut)
 		return;
 
-	/* If we're called from AAL, dev is NULL */
-	gamma = dev ? dev_get_drvdata(dev) : NULL;
-
-	if (gamma && gamma->data) {
-		lut_diff = gamma->data->lut_diff;
-		lut_size = gamma->data->lut_size;
-	} else {
-		lut_diff = false;
-		lut_size = 512;
-	}
-
-	lut_base = regs + DISP_GAMMA_LUT;
+	lut_base = gamma->regs + DISP_GAMMA_LUT;
 	lut = (struct drm_color_lut *)state->gamma_lut->data;
-	for (i = 0; i < lut_size; i++) {
+	for (i = 0; i < gamma->data->lut_size; i++) {
 		struct drm_color_lut diff, hwlut;
 
 		hwlut.red = drm_color_lut_extract(lut[i].red, 10);
 		hwlut.green = drm_color_lut_extract(lut[i].green, 10);
 		hwlut.blue = drm_color_lut_extract(lut[i].blue, 10);
 
-		if (!lut_diff || (i % 2 == 0)) {
+		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);
@@ -124,19 +111,12 @@ void mtk_gamma_set_common(struct device *dev, void __iomem *regs, struct drm_crt
 		writel(word, lut_base + i * 4);
 	}
 
-	cfg_val = readl(regs + DISP_GAMMA_CFG);
+	cfg_val = readl(gamma->regs + DISP_GAMMA_CFG);
 
 	/* Enable the gamma table */
 	cfg_val |= FIELD_PREP(GAMMA_LUT_EN, 1);
 
-	writel(cfg_val, regs + DISP_GAMMA_CFG);
-}
-
-void mtk_gamma_set(struct device *dev, struct drm_crtc_state *state)
-{
-	struct mtk_disp_gamma *gamma = dev_get_drvdata(dev);
-
-	mtk_gamma_set_common(dev, gamma->regs, state);
+	cfg_val = readl(gamma->regs + DISP_GAMMA_CFG);
 }
 
 void mtk_gamma_config(struct device *dev, unsigned int w,