On 8/26/26 8:09 AM, Julien Stephan wrote:
> 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
A few of these macros are unused compare to the Linux implementation. If
that was on purpose we, should probably just remove those macros.
> +
> +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" },
We should be able to make this "mediatek,mt8195-disp-ethdr" (the fallback)
so that we don't have to keep adding more compatibles.
> + {}
nit: patches are inconsistent with style for this. I would prefer `{ }`
as that seems to be the most common.
> +};
> +
> +/*
> + * 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
>
