linux-kernel - [PATCH v4 2/9] drm/mediatek: dsi: Fix DSI RGB666 formats and definitions

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Message-ID: <20240206120748.136610-3-angelogioacchino.delregno@collabora.com>
Date: Tue,  6 Feb 2024 13:07:41 +0100
From: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
To: chunkuang.hu@...nel.org
Cc: fshao@...omium.org,
	p.zabel@...gutronix.de,
	airlied@...il.com,
	daniel@...ll.ch,
	matthias.bgg@...il.com,
	angelogioacchino.delregno@...labora.com,
	dri-devel@...ts.freedesktop.org,
	linux-mediatek@...ts.infradead.org,
	linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	kernel@...labora.com
Subject: [PATCH v4 2/9] drm/mediatek: dsi: Fix DSI RGB666 formats and definitions

The register bits definitions for RGB666 formats are wrong in multiple
ways: first, in the DSI_PS_SEL bits region, the Packed 18-bits RGB666
format is selected with bit 1, while the Loosely Packed one is bit 2,
and second - the definition name "LOOSELY_PS_18BIT_RGB666" is wrong
because the loosely packed format is 24 bits instead!

Either way, functions mtk_dsi_ps_control_vact() and mtk_dsi_ps_control()
do not even agree on the DSI_PS_SEL bit to set in DSI_PSCTRL: one sets
loosely packed (24) on RGB666, the other sets packed (18), and the other
way around for RGB666_PACKED.

Fixing this entire stack of issues is done in one go:
 - Use the correct bit for the Loosely Packed RGB666 definition
 - Rename LOOSELY_PS_18BIT_RGB666 to LOOSELY_PS_24BIT_RGB666
 - Change ps_bpp_mode in mtk_dsi_ps_control_vact() to set:
    - Loosely Packed, 24-bits for MIPI_DSI_FMT_RGB666
    - Packed, 18-bits for MIPI_DSI_FMT_RGB666_PACKED

Fixes: 2e54c14e310f ("drm/mediatek: Add DSI sub driver")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>
---
 drivers/gpu/drm/mediatek/mtk_dsi.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c b/drivers/gpu/drm/mediatek/mtk_dsi.c
index 3b7392c03b4d..9fbf293db1c8 100644
--- a/drivers/gpu/drm/mediatek/mtk_dsi.c
+++ b/drivers/gpu/drm/mediatek/mtk_dsi.c
@@ -71,8 +71,8 @@
 #define DSI_PS_WC			GENMASK(14, 0)
 #define DSI_PS_SEL			GENMASK(19, 16)
 #define PACKED_PS_16BIT_RGB565		(0 << 16)
-#define LOOSELY_PS_18BIT_RGB666		(1 << 16)
-#define PACKED_PS_18BIT_RGB666		(2 << 16)
+#define PACKED_PS_18BIT_RGB666		(1 << 16)
+#define LOOSELY_PS_24BIT_RGB666		(2 << 16)
 #define PACKED_PS_24BIT_RGB888		(3 << 16)
 
 #define DSI_VSA_NL		0x20
@@ -370,10 +370,10 @@ static void mtk_dsi_ps_control_vact(struct mtk_dsi *dsi)
 		ps_bpp_mode |= PACKED_PS_24BIT_RGB888;
 		break;
 	case MIPI_DSI_FMT_RGB666:
-		ps_bpp_mode |= PACKED_PS_18BIT_RGB666;
+		ps_bpp_mode |= LOOSELY_PS_24BIT_RGB666;
 		break;
 	case MIPI_DSI_FMT_RGB666_PACKED:
-		ps_bpp_mode |= LOOSELY_PS_18BIT_RGB666;
+		ps_bpp_mode |= PACKED_PS_18BIT_RGB666;
 		break;
 	case MIPI_DSI_FMT_RGB565:
 		ps_bpp_mode |= PACKED_PS_16BIT_RGB565;
@@ -427,7 +427,7 @@ static void mtk_dsi_ps_control(struct mtk_dsi *dsi)
 		dsi_tmp_buf_bpp = 3;
 		break;
 	case MIPI_DSI_FMT_RGB666:
-		tmp_reg = LOOSELY_PS_18BIT_RGB666;
+		tmp_reg = LOOSELY_PS_24BIT_RGB666;
 		dsi_tmp_buf_bpp = 3;
 		break;
 	case MIPI_DSI_FMT_RGB666_PACKED:
-- 
2.43.0