Re: [PATCH v8 15/19] drm/mediatek: Add mt8195 Embedded DisplayPort driver

[CK Hu <ck.hu@mediatek.com>]

Hi, Guillaume:

On Fri, 2022-02-18 at 15:54 +0100, Guillaume Ranquet wrote:
> From: Markus Schneider-Pargmann <msp@baylibre.com>
> 
> This patch adds a DisplayPort driver for the Mediatek mt8195 SoC.
> 
> It supports the mt8195, the embedded DisplayPort units. It offers
> hot-plug-detection and DisplayPort 1.4 with up to 4 lanes.
> 
> The driver creates a child device for the phy. The child device will
> never exist without the parent being active. As they are sharing a
> register range, the parent passes a regmap pointer to the child so
> that
> both can work with the same register range. The phy driver sets
> device
> data that is read by the parent to get the phy device that can be
> used
> to control the phy properties.
> 
> This driver is based on an initial version by
> Jason-JH.Lin <jason-jh.lin@mediatek.com>.
> 
> Signed-off-by: Markus Schneider-Pargmann <msp@baylibre.com>
> Signed-off-by: Guillaume Ranquet <granquet@baylibre.com>
> Reported-by: kernel test robot <lkp@intel.com>
> ---
>  drivers/gpu/drm/mediatek/Kconfig       |    7 +
>  drivers/gpu/drm/mediatek/Makefile      |    2 +
>  drivers/gpu/drm/mediatek/mtk_dp.c      | 2358
> ++++++++++++++++++++++++
>  drivers/gpu/drm/mediatek/mtk_dp_reg.h  |  568 ++++++
>  drivers/gpu/drm/mediatek/mtk_drm_drv.c |    1 +
>  drivers/gpu/drm/mediatek/mtk_drm_drv.h |    1 +
>  6 files changed, 2937 insertions(+)
>  create mode 100644 drivers/gpu/drm/mediatek/mtk_dp.c
>  create mode 100644 drivers/gpu/drm/mediatek/mtk_dp_reg.h
> 
> 

[snip]

> +
> +static u32 *mtk_dp_bridge_atomic_get_output_bus_fmts(struct
> drm_bridge *bridge,
> +						     struct
> drm_bridge_state *bridge_state,
> +						     struct
> drm_crtc_state *crtc_state,
> +						     struct
> drm_connector_state *conn_state,
> +						     unsigned int
> *num_output_fmts)
> +{
> +	u32 *output_fmts;
> +
> +	*num_output_fmts = 0;
> +	output_fmts = kcalloc(1, sizeof(*output_fmts), GFP_KERNEL);
> +	if (!output_fmts)
> +		return NULL;
> +	*num_output_fmts = 1;
> +	output_fmts[0] = MEDIA_BUS_FMT_FIXED;
> +	return output_fmts;
> +}
> +
> +static const u32 mt8195_input_fmts[] = {
> +	MEDIA_BUS_FMT_RGB888_1X24,
> +	MEDIA_BUS_FMT_YUV8_1X24,
> +	MEDIA_BUS_FMT_YUYV8_1X16,
> +};

This means DPINTF output format, right? Does DPINTF switch output
buffer format?

> +
> +static u32 *mtk_dp_bridge_atomic_get_input_bus_fmts(struct
> drm_bridge *bridge,
> +						    struct
> drm_bridge_state *bridge_state,
> +						    struct
> drm_crtc_state *crtc_state,
> +						    struct
> drm_connector_state *conn_state,
> +						    u32 output_fmt,
> +						    unsigned int
> *num_input_fmts)
> +{
> +	u32 *input_fmts;
> +	struct mtk_dp *mtk_dp = mtk_dp_from_bridge(bridge);
> +	struct drm_display_mode *mode = &crtc_state->adjusted_mode;
> +	struct drm_display_info *display_info =
> +		&conn_state->connector->display_info;
> +	u32 rx_linkrate;
> +	u32 bpp;
> +
> +	bpp = (display_info->color_formats & DRM_COLOR_FORMAT_YCRCB422)
> ? 16 :
> +									
> 	24;
> +	rx_linkrate = (u32)mtk_dp->train_info.link_rate * 27000;
> +	*num_input_fmts = 0;
> +	input_fmts = kcalloc(ARRAY_SIZE(mt8195_input_fmts),
> sizeof(*input_fmts),
> +			     GFP_KERNEL);
> +	if (!input_fmts)
> +		return NULL;
> +
> +	*num_input_fmts = ARRAY_SIZE(mt8195_input_fmts);
> +
> +	memcpy(input_fmts, mt8195_input_fmts,
> +	       sizeof(*input_fmts) * ARRAY_SIZE(mt8195_input_fmts));
> +
> +	if (((rx_linkrate * mtk_dp->train_info.lane_count) <
> +	     (mode->clock * 24 / 8)) &&
> +	    ((rx_linkrate * mtk_dp->train_info.lane_count) >
> +	     (mode->clock * 16 / 8)) &&
> +	    (display_info->color_formats & DRM_COLOR_FORMAT_YCRCB422))
> {
> +		kfree(input_fmts);
> +		input_fmts = kcalloc(1, sizeof(*input_fmts),
> GFP_KERNEL);
> +		*num_input_fmts = 1;
> +		input_fmts[0] = MEDIA_BUS_FMT_YUYV8_1X16;
> +	}
> +
> +	return input_fmts;
> +}
> +

[snip]

> +
> +static int mtk_dp_probe(struct platform_device *pdev)
> +{
> +	struct mtk_dp *mtk_dp;
> +	struct device *dev = &pdev->dev;
> +	int ret;
> +	int irq_num = 0;
> +
> +	mtk_dp = devm_kzalloc(dev, sizeof(*mtk_dp), GFP_KERNEL);
> +	if (!mtk_dp)
> +		return -ENOMEM;
> +
> +	mtk_dp->dev = dev;
> +
> +	irq_num = platform_get_irq(pdev, 0);
> +	if (irq_num < 0) {
> +		dev_err(dev, "failed to request dp irq resource\n");
> +		return irq_num;
> +	}
> +
> +	mtk_dp->next_bridge = devm_drm_of_get_bridge(dev, dev->of_node, 
> 1, 0);
> +	if (IS_ERR(mtk_dp->next_bridge)) {
> +		ret = PTR_ERR(mtk_dp->next_bridge);
> +		dev_err_probe(dev, ret, "Failed to get bridge\n");
> +		return ret;
> +	}
> +
> +	ret = mtk_dp_dt_parse(mtk_dp, pdev);
> +	if (ret)
> +		return ret;
> +
> +	mtk_dp_aux_init(mtk_dp);
> +
> +	ret = devm_request_threaded_irq(dev, irq_num, mtk_dp_hpd_event,
> +					mtk_dp_hpd_event_thread,
> +					IRQ_TYPE_LEVEL_HIGH,
> dev_name(dev),
> +					mtk_dp);

Embedded displayport is always connected, right? Why do we need process
hot plug? Move this to the patch of external displayport.

> +	if (ret) {
> +		dev_err(dev, "failed to request mediatek dptx irq\n");
> +		return -EPROBE_DEFER;
> +	}
> +
> +	mutex_init(&mtk_dp->dp_lock);

Why need dp_lock, please provide the case information.

> +	mutex_init(&mtk_dp->edid_lock);

edid_lock is necessary when irq exist.

> +
> +	platform_set_drvdata(pdev, mtk_dp);
> +
> +	mtk_dp->phy_dev = platform_device_register_data(dev, "mediatek-
> dp-phy",
> +							PLATFORM_DEVID_
> AUTO,
> +							&mtk_dp->regs,
> +							sizeof(struct
> regmap *));
> +	if (IS_ERR(mtk_dp->phy_dev)) {
> +		dev_err(dev, "Failed to create device mediatek-dp-phy:
> %ld\n",
> +			PTR_ERR(mtk_dp->phy_dev));
> +		return PTR_ERR(mtk_dp->phy_dev);
> +	}
> +
> +	mtk_dp_get_calibration_data(mtk_dp);
> +
> +	mtk_dp->phy = devm_phy_get(&mtk_dp->phy_dev->dev, "dp");
> +	if (IS_ERR(mtk_dp->phy)) {
> +		dev_err(dev, "Failed to get phy: %ld\n",
> PTR_ERR(mtk_dp->phy));
> +		platform_device_unregister(mtk_dp->phy_dev);
> +		return PTR_ERR(mtk_dp->phy);
> +	}
> +
> +	mtk_dp->bridge.funcs = &mtk_dp_bridge_funcs;
> +	mtk_dp->bridge.of_node = dev->of_node;
> +	mtk_dp->bridge.type = DRM_MODE_CONNECTOR_eDP;
> +
> +	mtk_dp->bridge.ops =
> +		DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID |
> DRM_BRIDGE_OP_HPD;

DRM_BRIDGE_OP_DETECT? DRM_BRIDGE_OP_HPD?

> +	drm_bridge_add(&mtk_dp->bridge);
> +
> +	pm_runtime_enable(dev);
> +	pm_runtime_get_sync(dev);
> +
> +	return 0;
> +}
> +
> 

[snip]

> diff --git a/drivers/gpu/drm/mediatek/mtk_dp_reg.h
> b/drivers/gpu/drm/mediatek/mtk_dp_reg.h
> new file mode 100644
> index 0000000000000..79952ac30e9e6
> --- /dev/null
> +++ b/drivers/gpu/drm/mediatek/mtk_dp_reg.h
> @@ -0,0 +1,568 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2019 MediaTek Inc.
> + * Copyright (c) 2021 BayLibre
> + */
> +#ifndef _MTK_DP_REG_H_
> +#define _MTK_DP_REG_H_
> +
> +#define MTK_DP_SIP_CONTROL_AARCH32 0x82000523
> +#define MTK_DP_SIP_ATF_VIDEO_UNMUTE 0x20
> +#define MTK_DP_SIP_ATF_EDP_VIDEO_UNMUTE 0x21
> +
> +#define DP_PHY_GLB_BIAS_GEN_00 0x0000
> +#define RG_XTP_GLB_BIAS_INTR_CTRL (0x1f << 16)
> +
> +#define DP_PHY_GLB_DPAUX_TX 0x0008
> +#define RG_CKM_PT0_CKTX_IMPSEL (0xf << 20)
> +
> +#define DP_PHY_LANE_TX_0 0x104
> +#define RG_XTP_LN0_TX_IMPSEL_PMOS (0xf << 12)
> +#define RG_XTP_LN0_TX_IMPSEL_NMOS (0xf << 16)
> +
> +#define DP_PHY_LANE_TX_1 0x204
> +#define RG_XTP_LN1_TX_IMPSEL_PMOS (0xf << 12)
> +#define RG_XTP_LN1_TX_IMPSEL_NMOS (0xf << 16)
> +
> +#define DP_PHY_LANE_TX_2 0x304
> +#define RG_XTP_LN2_TX_IMPSEL_PMOS (0xf << 12)
> +#define RG_XTP_LN2_TX_IMPSEL_NMOS (0xf << 16)
> +
> +#define DP_PHY_LANE_TX_3 0x404
> +#define RG_XTP_LN3_TX_IMPSEL_PMOS (0xf << 12)
> +#define RG_XTP_LN3_TX_IMPSEL_NMOS (0xf << 16)

These register should be controlled by dp_phy driver?

Regards,
CK

> +
> +#define TOP_OFFSET 0x2000
> +#define ENC0_OFFSET 0x3000
> +#define ENC1_OFFSET 0x3200
> +#define TRANS_OFFSET 0x3400
> +#define AUX_OFFSET 0x3600
> +#define SEC_OFFSET 0x4000
> +
>