On 8/26/26 8:09 AM, Julien Stephan wrote:
> DPI is one of the components of the video pipeline on some MediaTek
> SoCs, such as the MT8188: it is the timing generator interface
> feeding the HDMI TX. Sync polarities, porches and the interlace mode
> are taken from the struct display_timing selected from the EDID.
>
...
> +void mtk_dpi_config(struct udevice *dev, const struct display_timing *timing,
> + bool rgb)
> +{
> + struct mtk_dpintf_yc_limit limit;
> + struct mtk_dpintf_polarities dpi_pol;
> + struct mtk_dpintf_sync_param hsync;
> + struct mtk_dpintf_sync_param vsync_lodd = { 0 };
> + struct mtk_dpintf_sync_param vsync_leven = { 0 };
> + struct mtk_dpintf_sync_param vsync_rodd = { 0 };
> + struct mtk_dpintf_sync_param vsync_reven = { 0 };
nit: these can just be `{ }`.
> + bool interlaced = timing->flags & DISPLAY_FLAGS_INTERLACED;
> +
> + limit.c_bottom = 0x0010;
> + limit.c_top = 0x0FE0;
> + limit.y_bottom = 0x0010;
> + limit.y_top = 0x0FE0;
> +
> + dpi_pol.ck_pol = MTK_DPINTF_POLARITY_FALLING;
> + dpi_pol.de_pol = MTK_DPINTF_POLARITY_RISING;
> + dpi_pol.hsync_pol = timing->flags & DISPLAY_FLAGS_HSYNC_HIGH ?
> + MTK_DPINTF_POLARITY_RISING :
> + MTK_DPINTF_POLARITY_FALLING;
> + dpi_pol.vsync_pol = timing->flags & DISPLAY_FLAGS_VSYNC_HIGH ?
> + MTK_DPINTF_POLARITY_RISING :
> + MTK_DPINTF_POLARITY_FALLING;
> +
> + hsync.sync_width = timing->hsync_len.typ;
> + hsync.back_porch = timing->hback_porch.typ;
> + hsync.front_porch = timing->hfront_porch.typ;
> + hsync.shift_half_line = false;
> +
> + vsync_lodd.sync_width = timing->vsync_len.typ;
> + vsync_lodd.back_porch = timing->vback_porch.typ;
> + vsync_lodd.front_porch = timing->vfront_porch.typ;
> + vsync_lodd.shift_half_line = false;
> +
> + if (interlaced) {
> + vsync_leven = vsync_lodd;
> + vsync_leven.shift_half_line = true;
> + }
> +
> + mtk_dpi_sw_reset(dev, true);
> + mtk_dpi_config_pol(dev, &dpi_pol);
> +
> + mtk_dpi_config_hsync(dev, &hsync);
> + mtk_dpi_config_vsync_lodd(dev, &vsync_lodd);
> + mtk_dpi_config_vsync_rodd(dev, &vsync_rodd);
> + mtk_dpi_config_vsync_leven(dev, &vsync_leven);
> + mtk_dpi_config_vsync_reven(dev, &vsync_reven);
> +
> + mtk_dpi_config_interface(dev, interlaced);
> + if (interlaced)
> + mtk_dpi_config_fb_size(dev, timing->hactive.typ,
> + timing->vactive.typ / 2);
> + else
> + mtk_dpi_config_fb_size(dev, timing->hactive.typ,
> + timing->vactive.typ);
> +
> + mtk_dpi_config_input_2p(dev, true);
> + mtk_dpi_config_output_1t1p(dev, true);
> + mtk_dpi_config_channel_limit(dev, &limit);
> + mtk_dpi_config_bit_num(dev, MTK_DPINTF_OUT_BIT_NUM_8BITS);
> + mtk_dpi_config_channel_swap(dev, MTK_DPINTF_OUT_CHANNEL_SWAP_RGB);
> + mtk_dpi_internal_matrix_sel(dev, !rgb);
> + mtk_dpi_config_yc_map(dev, MTK_DPINTF_OUT_YC_MAP_RGB);
> + mtk_dpi_config_swap_input(dev, false);
> + mtk_dpi_sw_reset(dev, false);
> +}
> +
> +static const struct udevice_id mtk_dpi_ids[] = {
> + { .compatible = "mediatek,mt8188-dpi" },
Another one where mt8195 fallback should work.
> + {}
> +};
> +
> +U_BOOT_DRIVER(mtk_dpi) = {
> + .name = "mtk_dpi",
> + .id = UCLASS_MISC,
> + .of_match = mtk_dpi_ids,
> + .probe = mtk_disp_comp_probe,
> + .priv_auto = sizeof(struct mtk_disp_comp_priv),
> +};
> diff --git a/drivers/video/mediatek/mtk_dpi.h
> b/drivers/video/mediatek/mtk_dpi.h
> new file mode 100644
> index 00000000000..ccce83ec8d3
> --- /dev/null
> +++ b/drivers/video/mediatek/mtk_dpi.h
> @@ -0,0 +1,20 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Mediatek MT8188 DPI Support
> + *
> + * Copyright (c) 2026 BayLibre, SAS.
> + * Author: Julien Stephan <[email protected]>
> + */
> +
> +#ifndef _MTK_DPI_H
> +#define _MTK_DPI_H
> +
> +struct display_timing;
> +struct udevice;
> +
> +void mtk_dpi_hw_enable(struct udevice *dev);
> +void mtk_dpi_hw_disable(struct udevice *dev);
> +void mtk_dpi_config(struct udevice *dev, const struct display_timing *timing,
> + bool rgb);
> +
> +#endif
> diff --git a/drivers/video/mediatek/mtk_dpi_regs.h
> b/drivers/video/mediatek/mtk_dpi_regs.h
> new file mode 100644
> index 00000000000..54e370460f0
> --- /dev/null
> +++ b/drivers/video/mediatek/mtk_dpi_regs.h
Does this really need to be a separate header? Seems like we can just put
this stuff in the .c file.
> @@ -0,0 +1,113 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2026 MediaTek Inc.
> + * Copyright (c) 2026 BayLibre, SAS
> + */
> +
> +#ifndef __MTK_DPI_REGS_H
> +#define __MTK_DPI_REGS_H
> +
> +#define DPI_EN 0x00
> +#define EN (0x1 << 0)
> +
> +#define DPI_RST 0x04
> +#define RST (0x1 << 0)
> +
> +#define DPI_INTEN 0x08
> +#define INT_VSYNC_EN (0x1 << 0)
> +
> +#define DPI_CON 0x10
> +#define IN_RB_SWAP (0x1 << 1)
> +#define INTL_EN (0x1 << 2)
> +#define TDFP_EN (0x1 << 3)
> +#define YUV422_EN (0x1 << 5)
> +#define CSC_ENABLE (0x1 << 6)
> +#define OUTPUT_1T1P_EN (0x1 << 24)
> +#define INPUT_2P_EN (0x1 << 25)
> +
> +#define DPI_OUTPUT_SETTING 0x14
> +#define CH_SWAP 0
> +#define CH_SWAP_MASK (0x7 << 0)
> +#define SWAP_RGB 0x00
> +#define SWAP_GBR 0x01
> +#define SWAP_BRG 0x02
> +#define SWAP_RBG 0x03
> +#define SWAP_GRB 0x04
> +#define SWAP_BGR 0x05
> +#define DE_POL (0x1 << 12)
> +#define HSYNC_POL (0x1 << 13)
> +#define VSYNC_POL (0x1 << 14)
> +#define CK_POL (0x1 << 15)
> +#define OUT_BIT 18
> +#define OUT_BIT_MASK (0x3 << 18)
> +#define OUT_BIT_8 0x00
> +#define OUT_BIT_10 0x01
> +#define OUT_BIT_12 0x02
> +#define OUT_BIT_16 0x03
> +#define YC_MAP 20
> +#define YC_MAP_MASK (0x7 << 20)
> +#define YC_MAP_RGB 0x00
> +#define YC_MAP_CYCY 0x04
> +#define YC_MAP_YCYC 0x05
> +#define YC_MAP_CY 0x06
> +#define YC_MAP_YC 0x07
> +
> +#define DPI_SIZE 0x18
> +#define HSIZE 0
> +#define HSIZE_MASK (0x1FFF << 0)
> +#define VSIZE 16
> +#define VSIZE_MASK (0x1FFF << 16)
> +
> +#define DPI_DDR_SETTING 0x1C
> +#define DDR_EN (0x1 << 0)
> +#define DDR_4PHASE (0x1 << 2)
> +
> +#define DPI_TGEN_HWIDTH 0x20
> +#define HPW 0
> +#define HPW_MASK (0xFFF << 0)
> +
> +#define DPI_TGEN_HPORCH 0x24
> +#define HBP 0
> +#define HBP_MASK (0xFFF << 0)
> +#define HFP 16
> +#define HFP_MASK (0xFFF << 16)
> +
> +#define DPI_TGEN_VWIDTH 0x28
> +#define DPI_TGEN_VPORCH 0x2C
> +
> +#define VSYNC_WIDTH_SHIFT 0
> +#define VSYNC_WIDTH_MASK (0xFFF << 0)
> +#define VSYNC_HALF_LINE_SHIFT 16
> +#define VSYNC_HALF_LINE_MASK (0xFFF << 16)
> +#define VSYNC_BACK_PORCH_SHIFT 0
> +#define VSYNC_BACK_PORCH_MASK (0xFFF << 0)
> +#define VSYNC_FRONT_PORCH_SHIFT 16
> +#define VSYNC_FRONT_PORCH_MASK (0xFFF << 16)
> +
> +#define DPI_TGEN_VWIDTH_LEVEN 0x68
> +#define DPI_TGEN_VPORCH_LEVEN 0x6C
> +#define DPI_TGEN_VWIDTH_RODD 0x70
> +#define DPI_TGEN_VPORCH_RODD 0x74
> +#define DPI_TGEN_VWIDTH_REVEN 0x78
> +#define DPI_TGEN_VPORCH_REVEN 0x7C
> +
> +#define DPI_Y_LIMIT 0x98
> +#define Y_LIMINT_BOT 0
> +#define Y_LIMINT_BOT_MASK (0xFFF << 0)
> +#define Y_LIMINT_TOP 16
> +#define Y_LIMINT_TOP_MASK (0xFFF << 16)
> +
> +#define DPI_C_LIMIT 0x9C
> +#define C_LIMIT_BOT 0
> +#define C_LIMIT_BOT_MASK (0xFFF << 0)
> +#define C_LIMIT_TOP 16
> +#define C_LIMIT_TOP_MASK (0xFFF << 16)
> +
> +#define DPI_MATRIX_SET 0xB4
> +#define INT_MATRIX_SEL_MASK (0x1F << 0)
> +#define RGB_TO_BT709 0x03
> +
> +#define DPI_PATTERN0 0xF00
> +#define DPI_PATTERN_EN BIT(0)
> +#define DPI_PATTERN_COLOR_BAR (0x4 << 4)
> +#endif /* __MTK_DPI_REGS_H */
>
Also would be nice to use BIT()/GENMASK().
