The ETHDR is one of the components of the video pipeline on some
MediaTek SoCs, such as the MT8188. Only its mixer sub-block is used,
which is the block's first register window.

Signed-off-by: Julien Stephan <[email protected]>
---
 drivers/video/mediatek/mtk_ethdr.c | 76 ++++++++++++++++++++++++++++++++++++++
 drivers/video/mediatek/mtk_ethdr.h | 16 ++++++++
 2 files changed, 92 insertions(+)

diff --git a/drivers/video/mediatek/mtk_ethdr.c 
b/drivers/video/mediatek/mtk_ethdr.c
new file mode 100644
index 00000000000..531c95f53a1
--- /dev/null
+++ b/drivers/video/mediatek/mtk_ethdr.c
@@ -0,0 +1,76 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Mediatek Video ETHDR support
+ *
+ * Copyright (c) 2026 BayLibre, SAS.
+ * Author: Julien Stephan <[email protected]>
+ */
+
+#include <dm.h>
+
+#include "mtk_disp_comp.h"
+#include "mtk_ethdr.h"
+
+#define MIX_EN                 0xc
+#define MIX_ROI_SIZE           0x18
+#define MIX_DATAPATH_CON       0x1c
+#define OUTPUT_NO_RND          BIT(3)
+#define SOURCE_RGB_SEL         BIT(7)
+#define BACKGROUND_RELAY       (4 << 9)
+#define MIX_ROI_BGCLR          0x20
+#define BGCLR_BLACK            0xff000000
+#define MIX_SRC_CON            0x24
+
+#define MIX_SRC_L2_EN          BIT(2)
+#define L2_SRC_SEL             (2 << 20)
+#define L2_OUT_SEL             (2 << 22)
+
+#define MIX_FUNC_DCM0          0x120
+#define MIX_UPD_REG_CK_EN      BIT(0)
+#define MIX_FUNC_DCM1          0x124
+#define BG_CLR_CK_EN           BIT(7)
+#define MIX_CK_EN              BIT(9)
+#define MIX_FUNC_DCM_ENABLE    0xffffffff
+
+#define MIX_L2_CON             0x58
+#define NON_PREMULTI_SOURCE    (2 << 12)
+#define MIX_L2_SRC_SIZE                0x60
+
+void mtk_ethdr_config(struct udevice *dev, u16 width, u16 height)
+{
+       /* enable internal clocks */
+       mtk_disp_comp_write(dev, MIX_FUNC_DCM0, MIX_FUNC_DCM_ENABLE);
+       mtk_disp_comp_write(dev, MIX_FUNC_DCM1, MIX_FUNC_DCM_ENABLE);
+
+       /* enable mixer */
+       mtk_disp_comp_write(dev, MIX_EN, 0x1);
+
+       mtk_disp_comp_write(dev, MIX_ROI_SIZE, (height << 16) | width);
+       mtk_disp_comp_write(dev, MIX_DATAPATH_CON,
+                           OUTPUT_NO_RND | SOURCE_RGB_SEL);
+       mtk_disp_comp_write(dev, MIX_L2_SRC_SIZE, (height << 16) | width);
+       mtk_disp_comp_write(dev, MIX_ROI_BGCLR, BGCLR_BLACK);
+
+       /* only configure L2 since only rdma4 and rdma5 are used */
+       mtk_disp_comp_write(dev, MIX_L2_CON, NON_PREMULTI_SOURCE);
+       mtk_disp_comp_write(dev, MIX_SRC_CON,
+                           MIX_SRC_L2_EN | L2_SRC_SEL | L2_OUT_SEL);
+}
+
+static const struct udevice_id mtk_ethdr_ids[] = {
+       { .compatible = "mediatek,mt8188-disp-ethdr" },
+       {}
+};
+
+/*
+ * The mixer is the first register window ("mixer" in reg-names) of the
+ * ethdr block, so binding the ethdr node with default register index 0
+ * gives the mixer registers.
+ */
+U_BOOT_DRIVER(mtk_ethdr) = {
+       .name      = "mtk_ethdr",
+       .id        = UCLASS_MISC,
+       .of_match  = mtk_ethdr_ids,
+       .probe     = mtk_disp_comp_probe,
+       .priv_auto = sizeof(struct mtk_disp_comp_priv),
+};
diff --git a/drivers/video/mediatek/mtk_ethdr.h 
b/drivers/video/mediatek/mtk_ethdr.h
new file mode 100644
index 00000000000..038c658a704
--- /dev/null
+++ b/drivers/video/mediatek/mtk_ethdr.h
@@ -0,0 +1,16 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Mediatek Video ETHDR support
+ *
+ * Copyright (c) 2026 BayLibre, SAS.
+ * Author: Julien Stephan <[email protected]>
+ */
+
+#ifndef _MTK_ETHDR_H
+#define _MTK_ETHDR_H
+
+struct udevice;
+
+void mtk_ethdr_config(struct udevice *dev, u16 width, u16 height);
+
+#endif

-- 
2.54.0

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