Re: [PATCH 2/6] drm/bridge: synopsys: Add DW DPTX Controller support library

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On Sun, Mar 02, 2025 at 06:34:22PM +0800, Andy Yan wrote:
> 
> 
> Hi Dmitry,
>    Thank you for your review。
>    Please also review my inline reply.
>       
> 在 2025-03-02 02:14:19,"Dmitry Baryshkov" <dmitry.baryshkov@xxxxxxxxxx> 写道:
> >On Sun, Feb 23, 2025 at 07:30:25PM +0800, Andy Yan wrote:
> >> From: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
> >> 
> >> The DW DP TX Controller is compliant with the DisplayPort Specification
> >> Version 1.4 with the following features:
> >> 
> >> * DisplayPort 1.4a
> >> * Main Link: 1/2/4 lanes
> >> * Main Link Support 1.62Gbps, 2.7Gbps, 5.4Gbps and 8.1Gbps
> >> * AUX channel 1Mbps
> >> * Single Stream Transport(SST)
> >> * Multistream Transport (MST)
> >> *Type-C support (alternate mode)
> >> * HDCP 2.2, HDCP 1.3
> >> * Supports up to 8/10 bits per color component
> >> * Supports RBG, YCbCr4:4:4, YCbCr4:2:2, YCbCr4:2:0
> >> * Pixel clock up to 594MHz
> >> * I2S, SPDIF audio interface
> >> 
> >> Add library with common helpers to make it can be shared with
> >> other SoC.
> >> 
> >> Signed-off-by: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
> >> 
> >> drm/bridge: cleanup
> >
> >Stray line?
> 
> Sorry, will be removed.
> 
> >
> >> 
> >> ---
> >> 
> >>  drivers/gpu/drm/bridge/synopsys/Kconfig  |    7 +
> >>  drivers/gpu/drm/bridge/synopsys/Makefile |    1 +
> >>  drivers/gpu/drm/bridge/synopsys/dw-dp.c  | 2155 ++++++++++++++++++++++
> >>  include/drm/bridge/dw_dp.h               |   19 +
> >>  4 files changed, 2182 insertions(+)
> >>  create mode 100644 drivers/gpu/drm/bridge/synopsys/dw-dp.c
> >>  create mode 100644 include/drm/bridge/dw_dp.h
> >> 
> >> diff --git a/drivers/gpu/drm/bridge/synopsys/Kconfig b/drivers/gpu/drm/bridge/synopsys/Kconfig
> >> index f3ab2f985f8c..2c5e532410de 100644
> >> --- a/drivers/gpu/drm/bridge/synopsys/Kconfig
> >> +++ b/drivers/gpu/drm/bridge/synopsys/Kconfig
> >> @@ -1,4 +1,11 @@
> >>  # SPDX-License-Identifier: GPL-2.0-only
> >> +config DRM_DW_DP
> >> +	tristate
> >> +	select DRM_DISPLAY_HELPER
> >> +	select DRM_DISPLAY_DP_HELPER
> >> +	select DRM_KMS_HELPER
> >> +	select REGMAP_MMIO
> >> +
> >>  config DRM_DW_HDMI
> >>  	tristate
> >>  	select DRM_DISPLAY_HDMI_HELPER
> >> diff --git a/drivers/gpu/drm/bridge/synopsys/Makefile b/drivers/gpu/drm/bridge/synopsys/Makefile
> >> index 9dc376d220ad..4dada44029ac 100644
> >> --- a/drivers/gpu/drm/bridge/synopsys/Makefile
> >> +++ b/drivers/gpu/drm/bridge/synopsys/Makefile
> >> @@ -1,4 +1,5 @@
> >>  # SPDX-License-Identifier: GPL-2.0-only
> >> +obj-$(CONFIG_DRM_DW_DP) += dw-dp.o
> >>  obj-$(CONFIG_DRM_DW_HDMI) += dw-hdmi.o
> >>  obj-$(CONFIG_DRM_DW_HDMI_AHB_AUDIO) += dw-hdmi-ahb-audio.o
> >>  obj-$(CONFIG_DRM_DW_HDMI_GP_AUDIO) += dw-hdmi-gp-audio.o
> >> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-dp.c b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> >> new file mode 100644
> >> index 000000000000..6ecbe9851369
> >> --- /dev/null
> >> +++ b/drivers/gpu/drm/bridge/synopsys/dw-dp.c
> >> @@ -0,0 +1,2155 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +/*
> >> + * Synopsys DesignWare Cores DisplayPort Transmitter Controller
> >> + *
> >> + * Copyright (c) 2024 Rockchip Electronics Co., Ltd.
> >> + *
> >> + * Author: Andy Yan <andy.yan@xxxxxxxxxxxxxx>
> >> + */
> >> +#include <linux/bitfield.h>
> >> +#include <linux/clk.h>
> >> +#include <linux/component.h>
> >> +#include <linux/iopoll.h>
> >> +#include <linux/irq.h>
> >> +#include <linux/of_device.h>
> >> +#include <linux/of_graph.h>
> >> +#include <linux/platform_device.h>
> >> +#include <linux/regmap.h>
> >> +#include <linux/reset.h>
> >> +#include <linux/phy/phy.h>
> >> +#include <linux/unaligned.h>
> >> +
> >> +#include <drm/bridge/dw_dp.h>
> >> +#include <drm/drm_atomic_helper.h>
> >> +#include <drm/drm_bridge.h>
> >> +#include <drm/drm_bridge_connector.h>
> >> +#include <drm/display/drm_dp_helper.h>
> >> +#include <drm/display/drm_hdmi_helper.h>
> >> +#include <drm/drm_edid.h>
> >> +#include <drm/drm_of.h>
> >> +#include <drm/drm_print.h>
> >> +#include <drm/drm_probe_helper.h>
> >> +#include <drm/drm_simple_kms_helper.h>
> >> +
> >> +#include <uapi/linux/media-bus-format.h>
> >> +
> >> +#define DW_DP_VERSION_NUMBER			0x0000
> >> +#define DW_DP_VERSION_TYPE			0x0004
> >> +#define DW_DP_ID					0x0008
> >> +
> >> +#define DW_DP_CONFIG_REG1			0x0100
> >> +#define DW_DP_CONFIG_REG2			0x0104
> >> +#define DW_DP_CONFIG_REG3			0x0108
> >> +
> >> +#define DW_DP_CCTL				0x0200
> >> +#define FORCE_HPD				BIT(4)
> >> +#define DEFAULT_FAST_LINK_TRAIN_EN		BIT(2)
> >> +#define ENHANCE_FRAMING_EN			BIT(1)
> >> +#define SCRAMBLE_DIS				BIT(0)
> >> +#define DW_DP_SOFT_RESET_CTRL			0x0204
> >> +#define VIDEO_RESET				BIT(5)
> >> +#define AUX_RESET				BIT(4)
> >> +#define AUDIO_SAMPLER_RESET			BIT(3)
> >> +#define HDCP_MODULE_RESET			BIT(2)
> >> +#define PHY_SOFT_RESET				BIT(1)
> >> +#define CONTROLLER_RESET			BIT(0)
> >> +
> >> +#define DW_DP_VSAMPLE_CTRL			0x0300
> >> +#define PIXEL_MODE_SELECT			GENMASK(22, 21)
> >> +#define VIDEO_MAPPING				GENMASK(20, 16)
> >> +#define VIDEO_STREAM_ENABLE			BIT(5)
> >> +
> >> +#define DW_DP_VSAMPLE_STUFF_CTRL1		0x0304
> >> +
> >> +#define DW_DP_VSAMPLE_STUFF_CTRL2		0x0308
> >> +
> >> +#define DW_DP_VINPUT_POLARITY_CTRL		0x030c
> >> +#define DE_IN_POLARITY				BIT(2)
> >> +#define HSYNC_IN_POLARITY			BIT(1)
> >> +#define VSYNC_IN_POLARITY			BIT(0)
> >> +
> >> +#define DW_DP_VIDEO_CONFIG1			0x0310
> >> +#define HACTIVE					GENMASK(31, 16)
> >> +#define HBLANK					GENMASK(15, 2)
> >> +#define I_P					BIT(1)
> >> +#define R_V_BLANK_IN_OSC			BIT(0)
> >> +
> >> +#define DW_DP_VIDEO_CONFIG2			0x0314
> >> +#define VBLANK					GENMASK(31, 16)
> >> +#define VACTIVE					GENMASK(15, 0)
> >> +
> >> +#define DW_DP_VIDEO_CONFIG3			0x0318
> >> +#define H_SYNC_WIDTH				GENMASK(31, 16)
> >> +#define H_FRONT_PORCH				GENMASK(15, 0)
> >> +
> >> +#define DW_DP_VIDEO_CONFIG4			0x031c
> >> +#define V_SYNC_WIDTH				GENMASK(31, 16)
> >> +#define V_FRONT_PORCH				GENMASK(15, 0)
> >> +
> >> +#define DW_DP_VIDEO_CONFIG5			0x0320
> >> +#define INIT_THRESHOLD_HI			GENMASK(22, 21)
> >> +#define AVERAGE_BYTES_PER_TU_FRAC		GENMASK(19, 16)
> >> +#define INIT_THRESHOLD				GENMASK(13, 7)
> >> +#define AVERAGE_BYTES_PER_TU			GENMASK(6, 0)
> >> +
> >> +#define DW_DP_VIDEO_MSA1				0x0324
> >> +#define VSTART					GENMASK(31, 16)
> >> +#define HSTART					GENMASK(15, 0)
> >> +
> >> +#define DW_DP_VIDEO_MSA2			0x0328
> >> +#define MISC0					GENMASK(31, 24)
> >> +
> >> +#define DW_DP_VIDEO_MSA3			0x032c
> >> +#define MISC1					GENMASK(31, 24)
> >> +
> >> +#define DW_DP_VIDEO_HBLANK_INTERVAL		0x0330
> >> +#define HBLANK_INTERVAL_EN			BIT(16)
> >> +#define HBLANK_INTERVAL				GENMASK(15, 0)
> >> +
> >> +#define DW_DP_AUD_CONFIG1			0x0400
> >> +#define AUDIO_TIMESTAMP_VERSION_NUM		GENMASK(29, 24)
> >> +#define AUDIO_PACKET_ID				GENMASK(23, 16)
> >> +#define AUDIO_MUTE				BIT(15)
> >> +#define NUM_CHANNELS				GENMASK(14, 12)
> >> +#define HBR_MODE_ENABLE				BIT(10)
> >> +#define AUDIO_DATA_WIDTH			GENMASK(9, 5)
> >> +#define AUDIO_DATA_IN_EN			GENMASK(4, 1)
> >> +#define AUDIO_INF_SELECT			BIT(0)
> >> +
> >> +#define DW_DP_SDP_VERTICAL_CTRL			0x0500
> >> +#define EN_VERTICAL_SDP				BIT(2)
> >> +#define EN_AUDIO_STREAM_SDP			BIT(1)
> >> +#define EN_AUDIO_TIMESTAMP_SDP			BIT(0)
> >> +#define DW_DP_SDP_HORIZONTAL_CTRL		0x0504
> >> +#define EN_HORIZONTAL_SDP			BIT(2)
> >> +#define DW_DP_SDP_STATUS_REGISTER		0x0508
> >> +#define DW_DP_SDP_MANUAL_CTRL			0x050c
> >> +#define DW_DP_SDP_STATUS_EN			0x0510
> >> +
> >> +#define DW_DP_SDP_REGISTER_BANK			0x0600
> >> +#define SDP_REGS				GENMASK(31, 0)
> >> +
> >> +#define DW_DP_PHYIF_CTRL			0x0a00
> >> +#define PHY_WIDTH				BIT(25)
> >> +#define PHY_POWERDOWN				GENMASK(20, 17)
> >> +#define PHY_BUSY				GENMASK(15, 12)
> >> +#define SSC_DIS					BIT(16)
> >> +#define XMIT_ENABLE				GENMASK(11, 8)
> >> +#define PHY_LANES				GENMASK(7, 6)
> >> +#define PHY_RATE				GENMASK(5, 4)
> >> +#define TPS_SEL					GENMASK(3, 0)
> >> +
> >> +#define DW_DP_PHY_TX_EQ				0x0a04
> >> +#define DW_DP_CUSTOMPAT0			0x0a08
> >> +#define DW_DP_CUSTOMPAT1			0x0a0c
> >> +#define DW_DP_CUSTOMPAT2			0x0a10
> >> +#define DW_DP_HBR2_COMPLIANCE_SCRAMBLER_RESET	0x0a14
> >> +#define DW_DP_PHYIF_PWRDOWN_CTRL		0x0a18
> >> +
> >> +#define DW_DP_AUX_CMD				0x0b00
> >> +#define AUX_CMD_TYPE				GENMASK(31, 28)
> >> +#define AUX_ADDR				GENMASK(27, 8)
> >> +#define I2C_ADDR_ONLY				BIT(4)
> >> +#define AUX_LEN_REQ				GENMASK(3, 0)
> >> +
> >> +#define DW_DP_AUX_STATUS			0x0b04
> >> +#define AUX_TIMEOUT				BIT(17)
> >> +#define AUX_BYTES_READ				GENMASK(23, 19)
> >> +#define AUX_STATUS				GENMASK(7, 4)
> >> +
> >> +#define DW_DP_AUX_DATA0				0x0b08
> >> +#define DW_DP_AUX_DATA1				0x0b0c
> >> +#define DW_DP_AUX_DATA2				0x0b10
> >> +#define DW_DP_AUX_DATA3				0x0b14
> >> +
> >> +#define DW_DP_GENERAL_INTERRUPT			0x0d00
> >> +#define VIDEO_FIFO_OVERFLOW_STREAM0		BIT(6)
> >> +#define AUDIO_FIFO_OVERFLOW_STREAM0		BIT(5)
> >> +#define SDP_EVENT_STREAM0			BIT(4)
> >> +#define AUX_CMD_INVALID				BIT(3)
> >> +#define HDCP_EVENT				BIT(2)
> >> +#define AUX_REPLY_EVENT				BIT(1)
> >> +#define HPD_EVENT				BIT(0)
> >> +
> >> +#define DW_DP_GENERAL_INTERRUPT_ENABLE		0x0d04
> >> +#define HDCP_EVENT_EN				BIT(2)
> >> +#define AUX_REPLY_EVENT_EN			BIT(1)
> >> +#define HPD_EVENT_EN				BIT(0)
> >> +
> >> +#define DW_DP_HPD_STATUS			0x0d08
> >> +#define HPD_STATE				GENMASK(11, 9)
> >> +#define HPD_STATUS				BIT(8)
> >> +#define HPD_HOT_UNPLUG				BIT(2)
> >> +#define HPD_HOT_PLUG				BIT(1)
> >> +#define HPD_IRQ					BIT(0)
> >> +
> >> +#define DW_DP_HPD_INTERRUPT_ENABLE		0x0d0c
> >> +#define HPD_UNPLUG_ERR_EN			BIT(3)
> >> +#define HPD_UNPLUG_EN				BIT(2)
> >> +#define HPD_PLUG_EN				BIT(1)
> >> +#define HPD_IRQ_EN				BIT(0)
> >> +
> >> +#define DW_DP_HDCP_CFG				0x0e00
> >> +#define DPCD12PLUS				BIT(7)
> >> +#define CP_IRQ					BIT(6)
> >> +#define BYPENCRYPTION				BIT(5)
> >> +#define HDCP_LOCK				BIT(4)
> >> +#define ENCRYPTIONDISABLE			BIT(3)
> >> +#define ENABLE_HDCP_13				BIT(2)
> >> +#define ENABLE_HDCP				BIT(1)
> >> +
> >> +#define DW_DP_HDCP_OBS				0x0e04
> >> +#define HDCP22_RE_AUTHENTICATION_REQ		BIT(31)
> >> +#define HDCP22_AUTHENTICATION_FAILED		BIT(30)
> >> +#define HDCP22_AUTHENTICATION_SUCCESS		BIT(29)
> >> +#define HDCP22_CAPABLE_SINK			BIT(28)
> >> +#define HDCP22_SINK_CAP_CHECK_COMPLETE		BIT(27)
> >> +#define HDCP22_STATE				GENMASK(26, 24)
> >> +#define HDCP22_BOOTED				BIT(23)
> >> +#define HDCP13_BSTATUS				GENMASK(22, 19)
> >> +#define REPEATER				BIT(18)
> >> +#define HDCP_CAPABLE				BIT(17)
> >> +#define STATEE					GENMASK(16, 14)
> >> +#define STATEOEG				GENMASK(13, 11)
> >> +#define STATER					GENMASK(10, 8)
> >> +#define STATEA					GENMASK(7, 4)
> >> +#define SUBSTATEA				GENMASK(3, 1)
> >> +#define HDCPENGAGED				BIT(0)
> >> +
> >> +#define DW_DP_HDCP_APIINTCLR			0x0e08
> >> +#define DW_DP_HDCP_APIINTSTAT			0x0e0c
> >> +#define DW_DP_HDCP_APIINTMSK			0x0e10
> >> +#define HDCP22_GPIOINT				BIT(8)
> >> +#define HDCP_ENGAGED				BIT(7)
> >> +#define HDCP_FAILED				BIT(6)
> >> +#define KSVSHA1CALCDONEINT			BIT(5)
> >> +#define AUXRESPNACK7TIMES			BIT(4)
> >> +#define AUXRESPTIMEOUT				BIT(3)
> >> +#define AUXRESPDEFER7TIMES			BIT(2)
> >> +#define KSVACCESSINT				BIT(0)
> >> +
> >> +#define DW_DP_HDCP_KSVMEMCTRL			0x0e18
> >> +#define KSVSHA1STATUS				BIT(4)
> >> +#define KSVMEMACCESS				BIT(1)
> >> +#define KSVMEMREQUEST				BIT(0)
> >> +
> >> +#define DW_DP_HDCP_REG_BKSV0			0x3600
> >> +#define DW_DP_HDCP_REG_BKSV1			0x3604
> >> +#define DW_DP_HDCP_REG_ANCONF			0x3608
> >> +#define AN_BYPASS				BIT(0)
> >> +
> >> +#define DW_DP_HDCP_REG_AN0			0x360c
> >> +#define DW_DP_HDCP_REG_AN1			0x3610
> >> +#define DW_DP_HDCP_REG_RMLCTL			0x3614
> >> +#define ODPK_DECRYPT_ENABLE			BIT(0)
> >> +
> >> +#define DW_DP_HDCP_REG_RMLSTS			0x3618
> >> +#define IDPK_WR_OK_STS				BIT(6)
> >> +#define	IDPK_DATA_INDEX				GENMASK(5, 0)
> >> +#define DW_DP_HDCP_REG_SEED			0x361c
> >> +#define DW_DP_HDCP_REG_DPK0			0x3620
> >> +#define DW_DP_HDCP_REG_DPK1			0x3624
> >> +#define DW_DP_HDCP22_GPIOSTS			0x3628
> >> +#define DW_DP_HDCP22_GPIOCHNGSTS		0x362c
> >> +#define DW_DP_HDCP_REG_DPK_CRC			0x3630
> >> +
> >> +#define DW_DP_MAX_REGISTER			DW_DP_HDCP_REG_DPK_CRC
> >> +
> >> +#define SDP_REG_BANK_SIZE			16
> >> +
> >> +struct dw_dp_link_caps {
> >> +	bool enhanced_framing;
> >> +	bool tps3_supported;
> >> +	bool tps4_supported;
> >> +	bool fast_training;
> >> +	bool channel_coding;
> >> +	bool ssc;
> >> +};
> >> +
> >> +struct dw_dp_link_train_set {
> >> +	unsigned int voltage_swing[4];
> >> +	unsigned int pre_emphasis[4];
> >> +	bool voltage_max_reached[4];
> >> +	bool pre_max_reached[4];
> >> +};
> >> +
> >> +struct dw_dp_link_train {
> >> +	struct dw_dp_link_train_set request;
> >> +	struct dw_dp_link_train_set adjust;
> >> +	bool clock_recovered;
> >> +	bool channel_equalized;
> >> +};
> >> +
> >> +struct dw_dp_link {
> >> +	u8 dpcd[DP_RECEIVER_CAP_SIZE];
> >> +	unsigned char revision;
> >> +	unsigned int rate;
> >> +	unsigned int lanes;
> >> +	u8 sink_count;
> >> +	u8 vsc_sdp_supported;
> >> +	struct dw_dp_link_caps caps;
> >> +	struct dw_dp_link_train train;
> >> +	struct drm_dp_desc desc;
> >> +};
> >> +
> >> +struct dw_dp_video {
> >> +	struct drm_display_mode mode;
> >> +	u8 video_mapping;
> >> +	u8 pixel_mode;
> >> +	u8 color_format;
> >> +	u8 bpc;
> >> +	u8 bpp;
> >> +};
> >> +
> >> +struct dw_dp_sdp {
> >> +	struct dp_sdp_header header;
> >> +	u8 db[32];
> >
> >struct dp_sdp, please
> 
> Ok, will do.
> 
> >
> >> +	unsigned long flags;
> >> +};
> >> +
> >> +struct dw_dp_hotplug {
> >> +	bool long_hpd;
> >> +};
> >> +
> >> +struct dw_dp {
> >> +	struct drm_bridge bridge;
> >> +	struct device *dev;
> >> +	struct regmap *regmap;
> >> +	struct phy *phy;
> >> +	struct clk *apb_clk;
> >> +	struct clk *aux_clk;
> >> +	struct clk *i2s_clk;
> >> +	struct clk *spdif_clk;
> >> +	struct clk *hdcp_clk;
> >> +	struct reset_control *rstc;
> >> +	struct completion complete;
> >> +	int irq;
> >> +	struct work_struct hpd_work;
> >> +	struct dw_dp_hotplug hotplug;
> >> +	struct mutex irq_lock;
> >> +
> >> +	struct drm_dp_aux aux;
> >> +
> >> +	struct dw_dp_link link;
> >> +	struct dw_dp_video video;
> >> +	const struct dw_dp_plat_data *plat_data;
> >> +
> >> +	DECLARE_BITMAP(sdp_reg_bank, SDP_REG_BANK_SIZE);
> >> +};
> >> +
> >> +enum {
> >> +	DW_DP_RGB_6BIT,
> >> +	DW_DP_RGB_8BIT,
> >> +	DW_DP_RGB_10BIT,
> >> +	DW_DP_RGB_12BIT,
> >> +	DW_DP_RGB_16BIT,
> >> +	DW_DP_YCBCR444_8BIT,
> >> +	DW_DP_YCBCR444_10BIT,
> >> +	DW_DP_YCBCR444_12BIT,
> >> +	DW_DP_YCBCR444_16BIT,
> >> +	DW_DP_YCBCR422_8BIT,
> >> +	DW_DP_YCBCR422_10BIT,
> >> +	DW_DP_YCBCR422_12BIT,
> >> +	DW_DP_YCBCR422_16BIT,
> >> +	DW_DP_YCBCR420_8BIT,
> >> +	DW_DP_YCBCR420_10BIT,
> >> +	DW_DP_YCBCR420_12BIT,
> >> +	DW_DP_YCBCR420_16BIT,
> >> +};
> >> +
> >> +enum {
> >> +	DW_DP_MP_SINGLE_PIXEL,
> >> +	DW_DP_MP_DUAL_PIXEL,
> >> +	DW_DP_MP_QUAD_PIXEL,
> >> +};
> >> +
> >> +enum {
> >> +	DW_DP_SDP_VERTICAL_INTERVAL = BIT(0),
> >> +	DW_DP_SDP_HORIZONTAL_INTERVAL = BIT(1),
> >> +};
> >> +
> >> +enum {
> >> +	DW_DP_HPD_STATE_IDLE,
> >> +	DW_DP_HPD_STATE_UNPLUG,
> >> +	DP_DP_HPD_STATE_TIMEOUT = 4,
> >> +	DW_DP_HPD_STATE_PLUG = 7
> >> +};
> >> +
> >> +enum {
> >> +	DW_DP_PHY_PATTERN_NONE,
> >> +	DW_DP_PHY_PATTERN_TPS_1,
> >> +	DW_DP_PHY_PATTERN_TPS_2,
> >> +	DW_DP_PHY_PATTERN_TPS_3,
> >> +	DW_DP_PHY_PATTERN_TPS_4,
> >> +	DW_DP_PHY_PATTERN_SERM,
> >> +	DW_DP_PHY_PATTERN_PBRS7,
> >> +	DW_DP_PHY_PATTERN_CUSTOM_80BIT,
> >> +	DW_DP_PHY_PATTERN_CP2520_1,
> >> +	DW_DP_PHY_PATTERN_CP2520_2,
> >> +};
> >> +
> >> +struct dw_dp_output_format {
> >> +	u32 bus_format;
> >> +	u32 color_format;
> >> +	u8 video_mapping;
> >> +	u8 bpc;
> >> +	u8 bpp;
> >> +};
> >> +
> >> +static const struct dw_dp_output_format dw_dp_output_formats[] = {
> >> +	{ MEDIA_BUS_FMT_RGB101010_1X30, DRM_COLOR_FORMAT_RGB444, DW_DP_RGB_10BIT, 10, 30 },
> >> +	{ MEDIA_BUS_FMT_RGB888_1X24, DRM_COLOR_FORMAT_RGB444, DW_DP_RGB_8BIT, 8, 24 },
> >> +	{ MEDIA_BUS_FMT_YUV10_1X30, DRM_COLOR_FORMAT_YCBCR444, DW_DP_YCBCR444_10BIT, 10, 30 },
> >> +	{ MEDIA_BUS_FMT_YUV8_1X24, DRM_COLOR_FORMAT_YCBCR444, DW_DP_YCBCR444_8BIT, 8, 24},
> >> +	{ MEDIA_BUS_FMT_YUYV10_1X20, DRM_COLOR_FORMAT_YCBCR422, DW_DP_YCBCR422_10BIT, 10, 20 },
> >> +	{ MEDIA_BUS_FMT_YUYV8_1X16, DRM_COLOR_FORMAT_YCBCR422, DW_DP_YCBCR422_8BIT, 8, 16 },
> >> +	{ MEDIA_BUS_FMT_UYYVYY10_0_5X30, DRM_COLOR_FORMAT_YCBCR420, DW_DP_YCBCR420_10BIT, 10, 15 },
> >> +	{ MEDIA_BUS_FMT_UYYVYY8_0_5X24, DRM_COLOR_FORMAT_YCBCR420, DW_DP_YCBCR420_8BIT, 8, 12 },
> >> +	{ MEDIA_BUS_FMT_RGB666_1X24_CPADHI, DRM_COLOR_FORMAT_RGB444, DW_DP_RGB_6BIT, 6, 18 },
> >> +};
> >> +
> >> +static const struct dw_dp_output_format *dw_dp_get_output_format(u32 bus_format)
> >> +{
> >> +	unsigned int i;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(dw_dp_output_formats); i++)
> >> +		if (dw_dp_output_formats[i].bus_format == bus_format)
> >> +			return &dw_dp_output_formats[i];
> >> +
> >> +	return &dw_dp_output_formats[1];
> >
> >Why? Shouldn't it be NULL?
> 
> At first, we considered RGB888_1X24  to be universally applicable across all scenarios, 
> but upon re-evaluation, this assumption proved inaccurate. Specifically, RGB888 may
> encounter bandwidth limitations in high-resolution or high-refresh-rate environments
> 
> So returning NULL would be more appropriate here.
> 
> >
> >> +}
> >> +
> >> +static inline struct dw_dp *bridge_to_dp(struct drm_bridge *b)
> >> +{
> >> +	return container_of(b, struct dw_dp, bridge);
> >> +}
> >> +
> >> +static inline void dw_dp_phy_set_pattern(struct dw_dp *dp, u32 pattern)
> >> +{
> >> +	regmap_update_bits(dp->regmap, DW_DP_PHYIF_CTRL, TPS_SEL,
> >> +			   FIELD_PREP(TPS_SEL, pattern));
> >> +}
> >> +
> >> +static void dw_dp_phy_xmit_enable(struct dw_dp *dp, u32 lanes)
> >> +{
> >> +	u32 xmit_enable;
> >> +
> >> +	switch (lanes) {
> >> +	case 4:
> >> +	case 2:
> >> +	case 1:
> >> +		xmit_enable = GENMASK(lanes - 1, 0);
> >> +		break;
> >> +	case 0:
> >> +	default:
> >> +		xmit_enable = 0;
> >> +		break;
> >> +	}
> >> +
> >> +	regmap_update_bits(dp->regmap, DW_DP_PHYIF_CTRL, XMIT_ENABLE,
> >> +			   FIELD_PREP(XMIT_ENABLE, xmit_enable));
> >> +}
> >> +
> >> +static bool dw_dp_bandwidth_ok(struct dw_dp *dp,
> >> +			       const struct drm_display_mode *mode, u32 bpp,
> >> +			       unsigned int lanes, unsigned int rate)
> >> +{
> >> +	u32 max_bw, req_bw;
> >> +
> >> +	req_bw = mode->clock * bpp / 8;
> >> +	max_bw = lanes * rate;
> >> +	if (req_bw > max_bw)
> >> +		return false;
> >> +
> >> +	return true;
> >> +}
> >> +
> >> +static bool dw_dp_hpd_detect(struct dw_dp *dp)
> >> +{
> >> +	u32 value;
> >> +
> >> +	regmap_read(dp->regmap, DW_DP_HPD_STATUS, &value);
> >> +
> >> +	return FIELD_GET(HPD_STATE, value) == DW_DP_HPD_STATE_PLUG;
> >> +}
> >> +
> >> +static void dw_dp_link_caps_reset(struct dw_dp_link_caps *caps)
> >> +{
> >> +	caps->enhanced_framing = false;
> >> +	caps->tps3_supported = false;
> >> +	caps->tps4_supported = false;
> >> +	caps->fast_training = false;
> >> +	caps->channel_coding = false;
> >> +}
> >> +
> >> +static void dw_dp_link_reset(struct dw_dp_link *link)
> >> +{
> >> +	link->vsc_sdp_supported = 0;
> >> +	link->sink_count = 0;
> >> +	link->revision = 0;
> >> +	link->rate = 0;
> >> +	link->lanes = 0;
> >> +
> >> +	dw_dp_link_caps_reset(&link->caps);
> >> +	memset(link->dpcd, 0, sizeof(link->dpcd));
> >> +}
> >> +
> >> +static int dw_dp_link_power_up(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	int ret;
> >> +	u8 value;
> >> +
> >> +	if (link->revision < DP_DPCD_REV_11)
> >> +		return 0;
> >> +
> >> +	ret = drm_dp_dpcd_readb(&dp->aux, DP_SET_POWER, &value);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	value &= ~DP_SET_POWER_MASK;
> >> +	value |= DP_SET_POWER_D0;
> >> +
> >> +	ret = drm_dp_dpcd_writeb(&dp->aux, DP_SET_POWER, value);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	usleep_range(1000, 2000);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_link_power_down(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	int ret;
> >> +	u8 value;
> >> +
> >> +	if (link->revision < DP_DPCD_REV_11)
> >> +		return 0;
> >> +
> >> +	ret = drm_dp_dpcd_readb(&dp->aux, DP_SET_POWER, &value);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	value &= ~DP_SET_POWER_MASK;
> >> +	value |= DP_SET_POWER_D3;
> >> +
> >> +	ret = drm_dp_dpcd_writeb(&dp->aux, DP_SET_POWER, value);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >
> >Would you please mind pulling these two functions to DRM DP helpers?
> >There are enough users to make this into a common code.
> 
> Yes, when developing this patch, I had the same realization. 
> The processing logic for MSM/Cadence/ANX6345/tegra follows
> a similar approach.
> I had originally planned to defer this refactoring until the series of patches is accepted. 
> Additionally, I have other pending tasks in my TODO list, such as fully decoupling the 
> bridge driver and encoder/connector components across all Rockchip platforms。
> But I prioritize completing these foundational features before go to next steps,
> Is this acceptable ?

You can add necessary helpers as one of the first patches in the
series. Convert one or several platforms that use drm-misc (i.e. not
MSM, AMD, i915, nouveau) and send conversion of the rest of the
platforms as followups.

> 
> >
> >> +	return 0;
> >> +}
> >> +
> >> +static bool dw_dp_has_sink_count(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
> >> +				 const struct drm_dp_desc *desc)
> >> +{
> >> +	return dpcd[DP_DPCD_REV] >= DP_DPCD_REV_11 &&
> >> +	       dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT &&
> >> +	       !drm_dp_has_quirk(desc, DP_DPCD_QUIRK_NO_SINK_COUNT);
> >
> >
> >isn't it drm_dp_read_sink_count_cap() ?
> 
> I will have a try, since this drm_dp_read_sink_count_cap requires a connector parameter, 
> I need to figure out how to get the connector here.

Maybe Maxime's series will you here, see [1].

[1] https://lore.kernel.org/dri-devel/20250225-bridge-connector-v4-4-7ecb07b09cad@xxxxxxxxxx/

> 
> >
> >> +}
> >> +
> >> +static int dw_dp_link_parse(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	u8 dpcd;
> >> +	int ret;
> >> +
> >> +	dw_dp_link_reset(link);
> >> +
> >> +	ret = drm_dp_read_dpcd_caps(&dp->aux, link->dpcd);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	drm_dp_read_desc(&dp->aux, &link->desc, drm_dp_is_branch(link->dpcd));
> >> +
> >> +	if (dw_dp_has_sink_count(link->dpcd, &link->desc)) {
> >> +		ret = drm_dp_read_sink_count(&dp->aux);
> >> +		if (ret < 0)
> >> +			return ret;
> >> +
> >> +		link->sink_count = ret;
> >> +
> >> +		/* Dongle connected, but no display */
> >> +		if (!link->sink_count)
> >> +			return -ENODEV;
> >> +	}
> >> +
> >> +	ret = drm_dp_dpcd_readb(&dp->aux, DP_DPRX_FEATURE_ENUMERATION_LIST, &dpcd);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	link->vsc_sdp_supported = !!(dpcd & DP_VSC_SDP_EXT_FOR_COLORIMETRY_SUPPORTED);
> >> +
> >> +	link->revision = link->dpcd[DP_DPCD_REV];
> >> +	link->rate = min_t(u32, min(dp->plat_data->max_link_rate,
> >> +				    dp->phy->attrs.max_link_rate * 100),
> >> +			   drm_dp_max_link_rate(link->dpcd));
> >> +	link->lanes = min_t(u8, phy_get_bus_width(dp->phy),
> >> +			    drm_dp_max_lane_count(link->dpcd));
> >> +
> >> +	link->caps.enhanced_framing = drm_dp_enhanced_frame_cap(link->dpcd);
> >> +	link->caps.tps3_supported = drm_dp_tps3_supported(link->dpcd);
> >> +	link->caps.tps4_supported = drm_dp_tps4_supported(link->dpcd);
> >> +	link->caps.fast_training = drm_dp_fast_training_cap(link->dpcd);
> >> +	link->caps.channel_coding = drm_dp_channel_coding_supported(link->dpcd);
> >> +	link->caps.ssc = !!(link->dpcd[DP_MAX_DOWNSPREAD] & DP_MAX_DOWNSPREAD_0_5);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_phy_update_vs_emph(struct dw_dp *dp, unsigned int rate, unsigned int lanes,
> >> +				    struct dw_dp_link_train_set *train_set)
> >> +{
> >> +	union phy_configure_opts phy_cfg;
> >> +	unsigned int *vs, *pe;
> >> +	u8 buf[4];
> >> +	int i, ret;
> >> +
> >> +	vs = train_set->voltage_swing;
> >> +	pe = train_set->pre_emphasis;
> >> +
> >> +	for (i = 0; i < lanes; i++) {
> >> +		phy_cfg.dp.voltage[i] = vs[i];
> >> +		phy_cfg.dp.pre[i] = pe[i];
> >> +	}
> >> +
> >> +	phy_cfg.dp.lanes = lanes;
> >> +	phy_cfg.dp.link_rate = rate / 100;
> >> +	phy_cfg.dp.set_lanes = false;
> >> +	phy_cfg.dp.set_rate = false;
> >
> >You don't need to set lanes / link_rate if set_lanes and set_rate is
> >false.
> This is because the rk_udphy_dp_phy_configure function first verifies the rate and lane settings,
> treating any uninitialized parameters as invalid configurations

I think this breaks the API. One should not be verifying the fields
which are not to be set. Please update the PHY driver.

> 
> >
> >> +	phy_cfg.dp.set_voltages = true;
> >> +
> >> +	ret = phy_configure(dp->phy, &phy_cfg);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	for (i = 0; i < lanes; i++) {
> >> +		buf[i] = (vs[i] << DP_TRAIN_VOLTAGE_SWING_SHIFT) |
> >> +			 (pe[i] << DP_TRAIN_PRE_EMPHASIS_SHIFT);
> >> +		if (train_set->voltage_max_reached[i])
> >> +			buf[i] |= DP_TRAIN_MAX_SWING_REACHED;
> >> +		if (train_set->pre_max_reached[i])
> >> +			buf[i] |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;
> >> +	}
> >> +
> >> +	ret = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET, buf, lanes);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_link_train_update_vs_emph(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	struct dw_dp_link_train_set *request = &link->train.request;
> >> +
> >> +	return dw_dp_phy_update_vs_emph(dp, dp->link.rate, dp->link.lanes, request);
> >
> >Inline it mayeb?
> 
> Okay, will do。
> >
> >> +}
> >> +
> >> +static int dw_dp_phy_configure(struct dw_dp *dp, unsigned int rate,
> >> +			       unsigned int lanes, bool ssc)
> >> +{
> >> +	union phy_configure_opts phy_cfg;
> >> +	int ret;
> >> +
> >> +	/* Move PHY to P3 */
> >> +	regmap_update_bits(dp->regmap, DW_DP_PHYIF_CTRL, PHY_POWERDOWN,
> >> +			   FIELD_PREP(PHY_POWERDOWN, 0x3));
> >> +
> >> +	phy_cfg.dp.lanes = lanes;
> >> +	phy_cfg.dp.link_rate = rate / 100;
> >> +	phy_cfg.dp.ssc = ssc;
> >> +	phy_cfg.dp.set_lanes = true;
> >> +	phy_cfg.dp.set_rate = true;
> >> +	phy_cfg.dp.set_voltages = false;
> >> +	ret = phy_configure(dp->phy, &phy_cfg);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	regmap_update_bits(dp->regmap, DW_DP_PHYIF_CTRL, PHY_LANES,
> >> +			   FIELD_PREP(PHY_LANES, lanes / 2));
> >> +
> >> +	/* Move PHY to P0 */
> >> +	regmap_update_bits(dp->regmap, DW_DP_PHYIF_CTRL, PHY_POWERDOWN,
> >> +			   FIELD_PREP(PHY_POWERDOWN, 0x0));
> >> +
> >> +	dw_dp_phy_xmit_enable(dp, lanes);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_link_configure(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	u8 buf[2];
> >> +	int ret;
> >> +
> >> +	ret = dw_dp_phy_configure(dp, link->rate, link->lanes, link->caps.ssc);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	buf[0] = drm_dp_link_rate_to_bw_code(link->rate);
> >> +	buf[1] = link->lanes;
> >> +
> >> +	if (link->caps.enhanced_framing) {
> >> +		buf[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN;
> >> +		regmap_update_bits(dp->regmap, DW_DP_CCTL, ENHANCE_FRAMING_EN,
> >> +				   FIELD_PREP(ENHANCE_FRAMING_EN, 1));
> >> +	} else {
> >> +		regmap_update_bits(dp->regmap, DW_DP_CCTL, ENHANCE_FRAMING_EN,
> >> +				   FIELD_PREP(ENHANCE_FRAMING_EN, 0));
> >> +	}
> >> +
> >> +	ret = drm_dp_dpcd_write(&dp->aux, DP_LINK_BW_SET, buf, sizeof(buf));
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	buf[0] = link->caps.ssc ? DP_SPREAD_AMP_0_5 : 0;
> >> +	buf[1] = link->caps.channel_coding ? DP_SET_ANSI_8B10B : 0;
> >> +
> >> +	ret = drm_dp_dpcd_write(&dp->aux, DP_DOWNSPREAD_CTRL, buf, sizeof(buf));
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void dw_dp_link_train_init(struct dw_dp_link_train *train)
> >> +{
> >> +	struct dw_dp_link_train_set *request = &train->request;
> >> +	struct dw_dp_link_train_set *adjust = &train->adjust;
> >> +	unsigned int i;
> >> +
> >> +	for (i = 0; i < 4; i++) {
> >> +		request->voltage_swing[i] = 0;
> >> +		adjust->voltage_swing[i] = 0;
> >> +
> >> +		request->pre_emphasis[i] = 0;
> >> +		adjust->pre_emphasis[i] = 0;
> >> +
> >> +		request->voltage_max_reached[i] = false;
> >> +		adjust->voltage_max_reached[i] = false;
> >> +
> >> +		request->pre_max_reached[i] = false;
> >> +		adjust->pre_max_reached[i] = false;
> >> +	}
> >> +
> >> +	train->clock_recovered = false;
> >> +	train->channel_equalized = false;
> >> +}
> >> +
> >> +static bool dw_dp_link_train_valid(const struct dw_dp_link_train *train)
> >> +{
> >> +	return train->clock_recovered && train->channel_equalized;
> >> +}
> >> +
> >> +static int dw_dp_link_train_set_pattern(struct dw_dp *dp, u32 pattern)
> >> +{
> >> +	u8 buf = 0;
> >> +	int ret;
> >> +
> >> +	if (pattern && pattern != DP_TRAINING_PATTERN_4) {
> >> +		buf |= DP_LINK_SCRAMBLING_DISABLE;
> >> +
> >> +		regmap_update_bits(dp->regmap, DW_DP_CCTL, SCRAMBLE_DIS,
> >> +				   FIELD_PREP(SCRAMBLE_DIS, 1));
> >> +	} else {
> >> +		regmap_update_bits(dp->regmap, DW_DP_CCTL, SCRAMBLE_DIS,
> >> +				   FIELD_PREP(SCRAMBLE_DIS, 0));
> >> +	}
> >> +
> >> +	switch (pattern) {
> >> +	case DP_TRAINING_PATTERN_DISABLE:
> >> +		dw_dp_phy_set_pattern(dp, DW_DP_PHY_PATTERN_NONE);
> >> +		break;
> >> +	case DP_TRAINING_PATTERN_1:
> >> +		dw_dp_phy_set_pattern(dp, DW_DP_PHY_PATTERN_TPS_1);
> >> +		break;
> >> +	case DP_TRAINING_PATTERN_2:
> >> +		dw_dp_phy_set_pattern(dp, DW_DP_PHY_PATTERN_TPS_2);
> >> +		break;
> >> +	case DP_TRAINING_PATTERN_3:
> >> +		dw_dp_phy_set_pattern(dp, DW_DP_PHY_PATTERN_TPS_3);
> >> +		break;
> >> +	case DP_TRAINING_PATTERN_4:
> >> +		dw_dp_phy_set_pattern(dp, DW_DP_PHY_PATTERN_TPS_4);
> >> +		break;
> >> +	default:
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
> >> +				 buf | pattern);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static u8 dw_dp_voltage_max(u8 preemph)
> >> +{
> >> +	switch (preemph & DP_TRAIN_PRE_EMPHASIS_MASK) {
> >> +	case DP_TRAIN_PRE_EMPH_LEVEL_0:
> >> +		return DP_TRAIN_VOLTAGE_SWING_LEVEL_3;
> >> +	case DP_TRAIN_PRE_EMPH_LEVEL_1:
> >> +		return DP_TRAIN_VOLTAGE_SWING_LEVEL_2;
> >> +	case DP_TRAIN_PRE_EMPH_LEVEL_2:
> >> +		return DP_TRAIN_VOLTAGE_SWING_LEVEL_1;
> >> +	case DP_TRAIN_PRE_EMPH_LEVEL_3:
> >> +	default:
> >> +		return DP_TRAIN_VOLTAGE_SWING_LEVEL_0;
> >> +	}
> >> +}
> >> +
> >> +static void dw_dp_link_get_adjustments(struct dw_dp_link *link,
> >> +				       u8 status[DP_LINK_STATUS_SIZE])
> >> +{
> >> +	struct dw_dp_link_train_set *adjust = &link->train.adjust;
> >> +	u8 v = 0;
> >> +	u8 p = 0;
> >> +	unsigned int i;
> >> +
> >> +	for (i = 0; i < link->lanes; i++) {
> >> +		v = drm_dp_get_adjust_request_voltage(status, i);
> >> +		p = drm_dp_get_adjust_request_pre_emphasis(status, i);
> >> +		if (p >=  DP_TRAIN_PRE_EMPH_LEVEL_3) {
> >> +			adjust->pre_emphasis[i] = DP_TRAIN_PRE_EMPH_LEVEL_3 >>
> >> +						  DP_TRAIN_PRE_EMPHASIS_SHIFT;
> >> +			adjust->pre_max_reached[i] = true;
> >> +		} else {
> >> +			adjust->pre_emphasis[i] = p >> DP_TRAIN_PRE_EMPHASIS_SHIFT;
> >> +			adjust->pre_max_reached[i] = false;
> >> +		}
> >> +		v = min(v, dw_dp_voltage_max(p));
> >> +		if (v >= DP_TRAIN_VOLTAGE_SWING_LEVEL_3) {
> >> +			adjust->voltage_swing[i] = DP_TRAIN_VOLTAGE_SWING_LEVEL_3 >>
> >> +						   DP_TRAIN_VOLTAGE_SWING_SHIFT;
> >> +			adjust->voltage_max_reached[i] = true;
> >> +		} else {
> >> +			adjust->voltage_swing[i] = v >> DP_TRAIN_VOLTAGE_SWING_SHIFT;
> >> +			adjust->voltage_max_reached[i] = false;
> >> +		}
> >> +	}
> >> +}
> >> +
> >> +static void dw_dp_link_train_adjust(struct dw_dp_link_train *train)
> >> +{
> >> +	struct dw_dp_link_train_set *request = &train->request;
> >> +	struct dw_dp_link_train_set *adjust = &train->adjust;
> >> +	unsigned int i;
> >> +
> >> +	for (i = 0; i < 4; i++) {
> >
> >Shouldn't it be a loop up to link->lanes?
> 
> Yeah, this makes sense。
> 
> 
> >
> >> +		if (request->voltage_swing[i] != adjust->voltage_swing[i])
> >> +			request->voltage_swing[i] = adjust->voltage_swing[i];
> >> +		if (request->voltage_max_reached[i] != adjust->voltage_max_reached[i])
> >> +			request->voltage_max_reached[i] = adjust->voltage_max_reached[i];
> >> +	}
> >> +
> >> +	for (i = 0; i < 4; i++) {
> >> +		if (request->pre_emphasis[i] != adjust->pre_emphasis[i])
> >> +			request->pre_emphasis[i] = adjust->pre_emphasis[i];
> >> +		if (request->pre_max_reached[i] != adjust->pre_max_reached[i])
> >> +			request->pre_max_reached[i] = adjust->pre_max_reached[i];
> >
> >Why do you need separate request and adjustment structs?
> 
> I need to think about this issue further and will confirm how to proceed later.

Thanks! I really like your link training implementation, it is pretty
clear.

> 
> 
> >
> >> +	}
> >> +}
> >> +
> >> +static int dw_dp_link_clock_recovery(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	u8 status[DP_LINK_STATUS_SIZE];
> >> +	unsigned int tries = 0;
> >> +	int ret;
> >> +
> >> +	ret = dw_dp_link_train_set_pattern(dp, DP_TRAINING_PATTERN_1);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	for (;;) {
> >> +		ret = dw_dp_link_train_update_vs_emph(dp);
> >> +		if (ret)
> >> +			return ret;
> >> +
> >> +		drm_dp_link_train_clock_recovery_delay(&dp->aux, link->dpcd);
> >> +
> >> +		ret = drm_dp_dpcd_read_link_status(&dp->aux, status);
> >> +		if (ret < 0) {
> >> +			dev_err(dp->dev, "failed to read link status: %d\n", ret);
> >> +			return ret;
> >> +		}
> >> +
> >> +		if (drm_dp_clock_recovery_ok(status, link->lanes)) {
> >> +			link->train.clock_recovered = true;
> >> +			break;
> >> +		}
> >> +
> >> +		dw_dp_link_get_adjustments(link, status);
> >> +
> >> +		if (link->train.request.voltage_swing[0] ==
> >> +		    link->train.adjust.voltage_swing[0])
> >
> >Should this take all lanes to account? I think it might be posssible to
> >drop the adjust / request split and adjust tries in
> >dw_dp_link_get_adjustments() instead.
> 
> Let me figure it out later。
> 
> >
> >> +			tries++;
> >> +		else
> >> +			tries = 0;
> >> +
> >> +		if (tries == 5)
> >> +			break;
> >> +
> >> +		dw_dp_link_train_adjust(&link->train);
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_link_channel_equalization(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	u8 status[DP_LINK_STATUS_SIZE], pattern;
> >> +	unsigned int tries;
> >> +	int ret;
> >> +
> >> +	if (link->caps.tps4_supported)
> >> +		pattern = DP_TRAINING_PATTERN_4;
> >> +	else if (link->caps.tps3_supported)
> >> +		pattern = DP_TRAINING_PATTERN_3;
> >> +	else
> >> +		pattern = DP_TRAINING_PATTERN_2;
> >> +	ret = dw_dp_link_train_set_pattern(dp, pattern);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	for (tries = 1; tries < 5; tries++) {
> >> +		ret = dw_dp_link_train_update_vs_emph(dp);
> >> +		if (ret)
> >> +			return ret;
> >> +
> >> +		drm_dp_link_train_channel_eq_delay(&dp->aux, link->dpcd);
> >> +
> >> +		ret = drm_dp_dpcd_read_link_status(&dp->aux, status);
> >> +		if (ret < 0)
> >> +			return ret;
> >> +
> >> +		if (!drm_dp_clock_recovery_ok(status, link->lanes)) {
> >> +			dev_err(dp->dev, "clock recovery lost while equalizing channel\n");
> >> +			link->train.clock_recovered = false;
> >> +			break;
> >> +		}
> >> +
> >> +		if (drm_dp_channel_eq_ok(status, link->lanes)) {
> >> +			link->train.channel_equalized = true;
> >> +			break;
> >> +		}
> >> +
> >> +		dw_dp_link_get_adjustments(link, status);
> >> +		dw_dp_link_train_adjust(&link->train);
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_link_downgrade(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	struct dw_dp_video *video = &dp->video;
> >> +
> >> +	switch (link->rate) {
> >> +	case 162000:
> >> +		return -EINVAL;
> >> +	case 270000:
> >> +		link->rate = 162000;
> >> +		break;
> >> +	case 540000:
> >> +		link->rate = 270000;
> >> +		break;
> >> +	case 810000:
> >> +		link->rate = 540000;
> >> +		break;
> >> +	}
> >> +
> >> +	if (!dw_dp_bandwidth_ok(dp, &video->mode, video->bpp, link->lanes,
> >> +				link->rate))
> >> +		return -E2BIG;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_link_train_full(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	int ret;
> >> +
> >> +retry:
> >> +	dw_dp_link_train_init(&link->train);
> >> +
> >> +	dev_dbg(dp->dev, "full-training link: %u lane%s at %u MHz\n",
> >> +		link->lanes, (link->lanes > 1) ? "s" : "", link->rate / 100);
> >> +
> >> +	ret = dw_dp_link_configure(dp);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "failed to configure DP link: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = dw_dp_link_clock_recovery(dp);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "clock recovery failed: %d\n", ret);
> >> +		goto out;
> >> +	}
> >> +
> >> +	if (!link->train.clock_recovered) {
> >> +		dev_err(dp->dev, "clock recovery failed, downgrading link\n");
> >> +
> >> +		ret = dw_dp_link_downgrade(dp);
> >> +		if (ret < 0)
> >> +			goto out;
> >> +		else
> >> +			goto retry;
> >> +	}
> >> +
> >> +	dev_dbg(dp->dev, "clock recovery succeeded\n");
> >> +
> >> +	ret = dw_dp_link_channel_equalization(dp);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "channel equalization failed: %d\n", ret);
> >> +		goto out;
> >> +	}
> >> +
> >> +	if (!link->train.channel_equalized) {
> >> +		dev_err(dp->dev, "channel equalization failed, downgrading link\n");
> >> +
> >> +		ret = dw_dp_link_downgrade(dp);
> >> +		if (ret < 0)
> >> +			goto out;
> >> +		else
> >> +			goto retry;
> >> +	}
> >> +
> >> +	dev_dbg(dp->dev, "channel equalization succeeded\n");
> >> +
> >> +out:
> >> +	dw_dp_link_train_set_pattern(dp, DP_TRAINING_PATTERN_DISABLE);
> >> +	return ret;
> >> +}
> >> +
> >> +static int dw_dp_link_train_fast(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	int ret;
> >> +	u8 status[DP_LINK_STATUS_SIZE];
> >> +	u8 pattern;
> >> +
> >> +	dw_dp_link_train_init(&link->train);
> >> +
> >> +	dev_dbg(dp->dev, "fast-training link: %u lane%s at %u MHz\n",
> >> +		link->lanes, (link->lanes > 1) ? "s" : "", link->rate / 100);
> >> +
> >> +	ret = dw_dp_link_configure(dp);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "failed to configure DP link: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = dw_dp_link_train_set_pattern(dp, DP_TRAINING_PATTERN_1);
> >> +	if (ret)
> >> +		goto out;
> >> +
> >> +	usleep_range(500, 1000);
> >> +
> >> +	if (link->caps.tps4_supported)
> >> +		pattern = DP_TRAINING_PATTERN_4;
> >> +	else if (link->caps.tps3_supported)
> >> +		pattern = DP_TRAINING_PATTERN_3;
> >> +	else
> >> +		pattern = DP_TRAINING_PATTERN_2;
> >> +	ret = dw_dp_link_train_set_pattern(dp, pattern);
> >> +	if (ret)
> >> +		goto out;
> >> +
> >> +	usleep_range(500, 1000);
> >> +
> >> +	ret = drm_dp_dpcd_read_link_status(&dp->aux, status);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "failed to read link status: %d\n", ret);
> >> +		goto out;
> >> +	}
> >> +
> >> +	if (!drm_dp_clock_recovery_ok(status, link->lanes)) {
> >> +		dev_err(dp->dev, "clock recovery failed\n");
> >> +		ret = -EIO;
> >> +		goto out;
> >> +	}
> >> +
> >> +	if (!drm_dp_channel_eq_ok(status, link->lanes)) {
> >> +		dev_err(dp->dev, "channel equalization failed\n");
> >> +		ret = -EIO;
> >> +		goto out;
> >> +	}
> >> +
> >> +out:
> >> +	dw_dp_link_train_set_pattern(dp, DP_TRAINING_PATTERN_DISABLE);
> >> +	return ret;
> >> +}
> >> +
> >> +static int dw_dp_link_train(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	int ret;
> >> +
> >> +	if (link->caps.fast_training) {
> >> +		if (dw_dp_link_train_valid(&link->train)) {
> >> +			ret = dw_dp_link_train_fast(dp);
> >> +			if (ret < 0)
> >> +				dev_err(dp->dev, "fast link training failed: %d\n", ret);
> >> +			else
> >> +				return 0;
> >> +		}
> >> +	}
> >> +
> >> +	ret = dw_dp_link_train_full(dp);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "full link training failed: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dw_dp_send_sdp(struct dw_dp *dp, struct dw_dp_sdp *sdp)
> >> +{
> >> +	const u8 *payload = sdp->db;
> >> +	u32 reg;
> >> +	int i, nr;
> >> +
> >> +	nr = find_first_zero_bit(dp->sdp_reg_bank, SDP_REG_BANK_SIZE);
> >> +	if (nr < SDP_REG_BANK_SIZE)
> >> +		set_bit(nr, dp->sdp_reg_bank);
> >> +	else
> >> +		return -EBUSY;
> >> +
> >> +	reg = DW_DP_SDP_REGISTER_BANK + nr * 9 * 4;
> >> +
> >> +	/* SDP header */
> >> +	regmap_write(dp->regmap, reg, get_unaligned_le32(&sdp->header));
> >> +
> >> +	/* SDP data payload */
> >> +	for (i = 1; i < 9; i++, payload += 4)
> >> +		regmap_write(dp->regmap, reg + i * 4,
> >> +			     FIELD_PREP(SDP_REGS, get_unaligned_le32(payload)));
> >> +
> >> +	if (sdp->flags & DW_DP_SDP_VERTICAL_INTERVAL)
> >> +		regmap_update_bits(dp->regmap, DW_DP_SDP_VERTICAL_CTRL,
> >> +				   EN_VERTICAL_SDP << nr,
> >> +				   EN_VERTICAL_SDP << nr);
> >> +
> >> +	if (sdp->flags & DW_DP_SDP_HORIZONTAL_INTERVAL)
> >> +		regmap_update_bits(dp->regmap, DW_DP_SDP_HORIZONTAL_CTRL,
> >> +				   EN_HORIZONTAL_SDP << nr,
> >> +				   EN_HORIZONTAL_SDP << nr);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void dw_dp_vsc_sdp_pack(const struct drm_dp_vsc_sdp *vsc,
> >> +			       struct dw_dp_sdp *sdp)
> >
> >Use drm_dp_vsc_sdp_pack() instead.
> 
> Ok, I will try。
> 
> >
> >> +{
> >> +	sdp->header.HB0 = 0;
> >> +	sdp->header.HB1 = DP_SDP_VSC;
> >> +	sdp->header.HB2 = vsc->revision;
> >> +	sdp->header.HB3 = vsc->length;
> >> +
> >> +	sdp->db[16] = (vsc->pixelformat & 0xf) << 4;
> >> +	sdp->db[16] |= vsc->colorimetry & 0xf;
> >> +
> >> +	switch (vsc->bpc) {
> >> +	case 8:
> >> +		sdp->db[17] = 0x1;
> >> +		break;
> >> +	case 10:
> >> +		sdp->db[17] = 0x2;
> >> +		break;
> >> +	case 12:
> >> +		sdp->db[17] = 0x3;
> >> +		break;
> >> +	case 16:
> >> +		sdp->db[17] = 0x4;
> >> +		break;
> >> +	case 6:
> >> +	default:
> >> +		break;
> >> +	}
> >> +
> >> +	if (vsc->dynamic_range == DP_DYNAMIC_RANGE_CTA)
> >> +		sdp->db[17] |= 0x80;
> >> +
> >> +	sdp->db[18] = vsc->content_type & 0x7;
> >> +
> >> +	sdp->flags |= DW_DP_SDP_VERTICAL_INTERVAL;
> >> +}
> >> +
> >> +static int dw_dp_send_vsc_sdp(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_video *video = &dp->video;
> >> +	struct drm_dp_vsc_sdp vsc = {};
> >> +	struct dw_dp_sdp sdp = {};
> >> +
> >> +	vsc.revision = 0x5;
> >> +	vsc.length = 0x13;
> >> +
> >> +	switch (video->color_format) {
> >> +	case DRM_COLOR_FORMAT_YCBCR444:
> >> +		vsc.pixelformat = DP_PIXELFORMAT_YUV444;
> >> +		break;
> >> +	case DRM_COLOR_FORMAT_YCBCR420:
> >> +		vsc.pixelformat = DP_PIXELFORMAT_YUV420;
> >> +		break;
> >> +	case DRM_COLOR_FORMAT_YCBCR422:
> >> +		vsc.pixelformat = DP_PIXELFORMAT_YUV422;
> >> +		break;
> >> +	case DRM_COLOR_FORMAT_RGB444:
> >> +	default:
> >> +		vsc.pixelformat = DP_PIXELFORMAT_RGB;
> >> +		break;
> >> +	}
> >> +
> >> +	if (video->color_format == DRM_COLOR_FORMAT_RGB444) {
> >> +		vsc.colorimetry = DP_COLORIMETRY_DEFAULT;
> >> +		vsc.dynamic_range = DP_DYNAMIC_RANGE_VESA;
> >> +	} else {
> >> +		vsc.colorimetry = DP_COLORIMETRY_BT709_YCC;
> >> +		vsc.dynamic_range = DP_DYNAMIC_RANGE_CTA;
> >> +	}
> >> +
> >> +	vsc.bpc = video->bpc;
> >> +	vsc.content_type = DP_CONTENT_TYPE_NOT_DEFINED;
> >> +
> >> +	dw_dp_vsc_sdp_pack(&vsc, &sdp);
> >> +
> >> +	return dw_dp_send_sdp(dp, &sdp);
> >> +}
> >> +
> >> +static int dw_dp_video_set_pixel_mode(struct dw_dp *dp, u8 pixel_mode)
> >> +{
> >> +	switch (pixel_mode) {
> >> +	case DW_DP_MP_SINGLE_PIXEL:
> >> +	case DW_DP_MP_DUAL_PIXEL:
> >> +	case DW_DP_MP_QUAD_PIXEL:
> >> +		break;
> >> +	default:
> >> +		return -EINVAL;
> >
> >Is it possible?
> 
> This IP is configurable for single/dual/quad pixel modes。
> It's  quad pixel mode on rk3588 and dual pixel mode on rk3576,
> so we add this check here.

My question was slightly different: is it possible to end up here in the
'default' branch?

> 
> 
> >
> >> +	}
> >> +
> >> +	regmap_update_bits(dp->regmap, DW_DP_VSAMPLE_CTRL, PIXEL_MODE_SELECT,
> >> +			   FIELD_PREP(PIXEL_MODE_SELECT, pixel_mode));
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static bool dw_dp_video_need_vsc_sdp(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	struct dw_dp_video *video = &dp->video;
> >> +
> >> +	if (!link->vsc_sdp_supported)
> >> +		return false;
> >> +
> >> +	if (video->color_format == DRM_COLOR_FORMAT_YCBCR420)
> >> +		return true;
> >> +
> >> +	return false;
> >> +}
> >> +
> >> +static int dw_dp_video_set_msa(struct dw_dp *dp, u8 color_format, u8 bpc,
> >> +			       u16 vstart, u16 hstart)
> >> +{
> >> +	u16 misc = 0;
> >> +
> >> +	if (dw_dp_video_need_vsc_sdp(dp))
> >> +		misc |= DP_MSA_MISC_COLOR_VSC_SDP;
> >> +
> >> +	switch (color_format) {
> >> +	case DRM_COLOR_FORMAT_RGB444:
> >> +		misc |= DP_MSA_MISC_COLOR_RGB;
> >> +		break;
> >> +	case DRM_COLOR_FORMAT_YCBCR444:
> >> +		misc |= DP_MSA_MISC_COLOR_YCBCR_444_BT709;
> >> +		break;
> >> +	case DRM_COLOR_FORMAT_YCBCR422:
> >> +		misc |= DP_MSA_MISC_COLOR_YCBCR_422_BT709;
> >> +		break;
> >> +	case DRM_COLOR_FORMAT_YCBCR420:
> >> +		break;
> >> +	default:
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	switch (bpc) {
> >> +	case 6:
> >> +		misc |= DP_MSA_MISC_6_BPC;
> >> +		break;
> >> +	case 8:
> >> +		misc |= DP_MSA_MISC_8_BPC;
> >> +		break;
> >> +	case 10:
> >> +		misc |= DP_MSA_MISC_10_BPC;
> >> +		break;
> >> +	case 12:
> >> +		misc |= DP_MSA_MISC_12_BPC;
> >> +		break;
> >> +	case 16:
> >> +		misc |= DP_MSA_MISC_16_BPC;
> >> +		break;
> >> +	default:
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_MSA1,
> >> +		     FIELD_PREP(VSTART, vstart) | FIELD_PREP(HSTART, hstart));
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_MSA2, FIELD_PREP(MISC0, misc));
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_MSA3, FIELD_PREP(MISC1, misc >> 8));
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void dw_dp_video_disable(struct dw_dp *dp)
> >> +{
> >> +	regmap_update_bits(dp->regmap, DW_DP_VSAMPLE_CTRL, VIDEO_STREAM_ENABLE,
> >> +			   FIELD_PREP(VIDEO_STREAM_ENABLE, 0));
> >> +}
> >> +
> >> +static int dw_dp_video_enable(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_video *video = &dp->video;
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	struct drm_display_mode *mode = &video->mode;
> >> +	u8 color_format = video->color_format;
> >> +	u8 bpc = video->bpc;
> >> +	u8 pixel_mode = video->pixel_mode;
> >> +	u8 bpp = video->bpp, init_threshold, vic;
> >> +	u32 hactive, hblank, h_sync_width, h_front_porch;
> >> +	u32 vactive, vblank, v_sync_width, v_front_porch;
> >> +	u32 vstart = mode->vtotal - mode->vsync_start;
> >> +	u32 hstart = mode->htotal - mode->hsync_start;
> >> +	u32 peak_stream_bandwidth, link_bandwidth;
> >> +	u32 average_bytes_per_tu, average_bytes_per_tu_frac;
> >> +	u32 ts, hblank_interval;
> >> +	u32 value;
> >> +	int ret;
> >> +
> >> +	ret = dw_dp_video_set_pixel_mode(dp, pixel_mode);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = dw_dp_video_set_msa(dp, color_format, bpc, vstart, hstart);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	regmap_update_bits(dp->regmap, DW_DP_VSAMPLE_CTRL, VIDEO_MAPPING,
> >> +			   FIELD_PREP(VIDEO_MAPPING, video->video_mapping));
> >> +
> >> +	/* Configure DW_DP_VINPUT_POLARITY_CTRL register */
> >> +	value = 0;
> >> +	if (mode->flags & DRM_MODE_FLAG_PHSYNC)
> >> +		value |= FIELD_PREP(HSYNC_IN_POLARITY, 1);
> >> +	if (mode->flags & DRM_MODE_FLAG_PVSYNC)
> >> +		value |= FIELD_PREP(VSYNC_IN_POLARITY, 1);
> >> +	regmap_write(dp->regmap, DW_DP_VINPUT_POLARITY_CTRL, value);
> >> +
> >> +	/* Configure DW_DP_VIDEO_CONFIG1 register */
> >> +	hactive = mode->hdisplay;
> >> +	hblank = mode->htotal - mode->hdisplay;
> >> +	value = FIELD_PREP(HACTIVE, hactive) | FIELD_PREP(HBLANK, hblank);
> >> +	if (mode->flags & DRM_MODE_FLAG_INTERLACE)
> >> +		value |= FIELD_PREP(I_P, 1);
> >> +	vic = drm_match_cea_mode(mode);
> >> +	if (vic == 5 || vic == 6 || vic == 7 ||
> >> +	    vic == 10 || vic == 11 || vic == 20 ||
> >> +	    vic == 21 || vic == 22 || vic == 39 ||
> >> +	    vic == 25 || vic == 26 || vic == 40 ||
> >> +	    vic == 44 || vic == 45 || vic == 46 ||
> >> +	    vic == 50 || vic == 51 || vic == 54 ||
> >> +	    vic == 55 || vic == 58 || vic  == 59)
> >> +		value |= R_V_BLANK_IN_OSC;
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_CONFIG1, value);
> >> +
> >> +	/* Configure DW_DP_VIDEO_CONFIG2 register */
> >> +	vblank = mode->vtotal - mode->vdisplay;
> >> +	vactive = mode->vdisplay;
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_CONFIG2,
> >> +		     FIELD_PREP(VBLANK, vblank) | FIELD_PREP(VACTIVE, vactive));
> >> +
> >> +	/* Configure DW_DP_VIDEO_CONFIG3 register */
> >> +	h_sync_width = mode->hsync_end - mode->hsync_start;
> >> +	h_front_porch = mode->hsync_start - mode->hdisplay;
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_CONFIG3,
> >> +		     FIELD_PREP(H_SYNC_WIDTH, h_sync_width) |
> >> +		     FIELD_PREP(H_FRONT_PORCH, h_front_porch));
> >> +
> >> +	/* Configure DW_DP_VIDEO_CONFIG4 register */
> >> +	v_sync_width = mode->vsync_end - mode->vsync_start;
> >> +	v_front_porch = mode->vsync_start - mode->vdisplay;
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_CONFIG4,
> >> +		     FIELD_PREP(V_SYNC_WIDTH, v_sync_width) |
> >> +		     FIELD_PREP(V_FRONT_PORCH, v_front_porch));
> >> +
> >> +	/* Configure DW_DP_VIDEO_CONFIG5 register */
> >> +	peak_stream_bandwidth = mode->clock * bpp / 8;
> >> +	link_bandwidth = (link->rate / 1000) * link->lanes;
> >> +	ts = peak_stream_bandwidth * 64 / link_bandwidth;
> >> +	average_bytes_per_tu = ts / 1000;
> >> +	average_bytes_per_tu_frac = ts / 100 - average_bytes_per_tu * 10;
> >> +	if (pixel_mode == DW_DP_MP_SINGLE_PIXEL) {
> >> +		if (average_bytes_per_tu < 6)
> >> +			init_threshold = 32;
> >> +		else if (hblank <= 80 && color_format != DRM_COLOR_FORMAT_YCBCR420)
> >> +			init_threshold = 12;
> >> +		else if (hblank <= 40 && color_format == DRM_COLOR_FORMAT_YCBCR420)
> >> +			init_threshold = 3;
> >> +		else
> >> +			init_threshold = 16;
> >> +	} else {
> >> +		u32 t1 = 0, t2 = 0, t3 = 0;
> >> +
> >> +		switch (bpc) {
> >> +		case 6:
> >> +			t1 = (4 * 1000 / 9) * link->lanes;
> >> +			break;
> >> +		case 8:
> >> +			if (color_format == DRM_COLOR_FORMAT_YCBCR422) {
> >> +				t1 = (1000 / 2) * link->lanes;
> >> +			} else {
> >> +				if (pixel_mode == DW_DP_MP_DUAL_PIXEL)
> >> +					t1 = (1000 / 3) * link->lanes;
> >> +				else
> >> +					t1 = (3000 / 16) * link->lanes;
> >> +			}
> >> +			break;
> >> +		case 10:
> >> +			if (color_format == DRM_COLOR_FORMAT_YCBCR422)
> >> +				t1 = (2000 / 5) * link->lanes;
> >> +			else
> >> +				t1 = (4000 / 15) * link->lanes;
> >> +			break;
> >> +		case 12:
> >> +			if (color_format == DRM_COLOR_FORMAT_YCBCR422) {
> >> +				if (pixel_mode == DW_DP_MP_DUAL_PIXEL)
> >> +					t1 = (1000 / 6) * link->lanes;
> >> +				else
> >> +					t1 = (1000 / 3) * link->lanes;
> >> +			} else {
> >> +				t1 = (2000 / 9) * link->lanes;
> >> +			}
> >> +			break;
> >> +		case 16:
> >> +			if (color_format != DRM_COLOR_FORMAT_YCBCR422 &&
> >> +			    pixel_mode == DW_DP_MP_DUAL_PIXEL)
> >> +				t1 = (1000 / 6) * link->lanes;
> >> +			else
> >> +				t1 = (1000 / 4) * link->lanes;
> >> +			break;
> >> +		default:
> >> +			return -EINVAL;
> >> +		}
> >> +
> >> +		if (color_format == DRM_COLOR_FORMAT_YCBCR420)
> >> +			t2 = (link->rate / 4) * 1000 / (mode->clock / 2);
> >> +		else
> >> +			t2 = (link->rate / 4) * 1000 / mode->clock;
> >> +
> >> +		if (average_bytes_per_tu_frac)
> >> +			t3 = average_bytes_per_tu + 1;
> >> +		else
> >> +			t3 = average_bytes_per_tu;
> >> +		init_threshold = t1 * t2 * t3 / (1000 * 1000);
> >> +		if (init_threshold <= 16 || average_bytes_per_tu < 10)
> >> +			init_threshold = 40;
> >> +	}
> >> +
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_CONFIG5,
> >> +		     FIELD_PREP(INIT_THRESHOLD_HI, init_threshold >> 6) |
> >> +		     FIELD_PREP(AVERAGE_BYTES_PER_TU_FRAC, average_bytes_per_tu_frac) |
> >> +		     FIELD_PREP(INIT_THRESHOLD, init_threshold) |
> >> +		     FIELD_PREP(AVERAGE_BYTES_PER_TU, average_bytes_per_tu));
> >> +
> >> +	/* Configure DW_DP_VIDEO_HBLANK_INTERVAL register */
> >> +	hblank_interval = hblank * (link->rate / 4) / mode->clock;
> >> +	regmap_write(dp->regmap, DW_DP_VIDEO_HBLANK_INTERVAL,
> >> +		     FIELD_PREP(HBLANK_INTERVAL_EN, 1) |
> >> +		     FIELD_PREP(HBLANK_INTERVAL, hblank_interval));
> >> +
> >> +	/* Video stream enable */
> >> +	regmap_update_bits(dp->regmap, DW_DP_VSAMPLE_CTRL, VIDEO_STREAM_ENABLE,
> >> +			   FIELD_PREP(VIDEO_STREAM_ENABLE, 1));
> >> +
> >> +	if (dw_dp_video_need_vsc_sdp(dp))
> >> +		dw_dp_send_vsc_sdp(dp);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void dw_dp_hpd_init(struct dw_dp *dp)
> >> +{
> >> +	/* Enable all HPD interrupts */
> >> +	regmap_update_bits(dp->regmap, DW_DP_HPD_INTERRUPT_ENABLE,
> >> +			   HPD_UNPLUG_EN | HPD_PLUG_EN | HPD_IRQ_EN,
> >> +			   FIELD_PREP(HPD_UNPLUG_EN, 1) |
> >> +			   FIELD_PREP(HPD_PLUG_EN, 1) |
> >> +			   FIELD_PREP(HPD_IRQ_EN, 1));
> >> +
> >> +	/* Enable all top-level interrupts */
> >> +	regmap_update_bits(dp->regmap, DW_DP_GENERAL_INTERRUPT_ENABLE,
> >> +			   HPD_EVENT_EN, FIELD_PREP(HPD_EVENT_EN, 1));
> >> +}
> >> +
> >> +static void dw_dp_aux_init(struct dw_dp *dp)
> >> +{
> >> +	regmap_update_bits(dp->regmap, DW_DP_GENERAL_INTERRUPT_ENABLE,
> >> +			   AUX_REPLY_EVENT_EN, FIELD_PREP(AUX_REPLY_EVENT_EN, 1));
> >> +}
> >> +
> >> +static void dw_dp_init_hw(struct dw_dp *dp)
> >> +{
> >> +	regmap_update_bits(dp->regmap, DW_DP_CCTL, DEFAULT_FAST_LINK_TRAIN_EN,
> >> +			   FIELD_PREP(DEFAULT_FAST_LINK_TRAIN_EN, 0));
> >> +
> >> +	dw_dp_hpd_init(dp);
> >> +	dw_dp_aux_init(dp);
> >> +}
> >> +
> >> +static int dw_dp_aux_write_data(struct dw_dp *dp, const u8 *buffer, size_t size)
> >> +{
> >> +	size_t i, j;
> >> +
> >> +	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
> >> +		size_t num = min_t(size_t, size - i * 4, 4);
> >> +		u32 value = 0;
> >> +
> >> +		for (j = 0; j < num; j++)
> >> +			value |= buffer[i * 4 + j] << (j * 8);
> >> +
> >> +		regmap_write(dp->regmap, DW_DP_AUX_DATA0 + i * 4, value);
> >> +	}
> >> +
> >> +	return size;
> >> +}
> >> +
> >> +static int dw_dp_aux_read_data(struct dw_dp *dp, u8 *buffer, size_t size)
> >> +{
> >> +	size_t i, j;
> >> +
> >> +	for (i = 0; i < DIV_ROUND_UP(size, 4); i++) {
> >> +		size_t num = min_t(size_t, size - i * 4, 4);
> >> +		u32 value;
> >> +
> >> +		regmap_read(dp->regmap, DW_DP_AUX_DATA0 + i * 4, &value);
> >> +
> >> +		for (j = 0; j < num; j++)
> >> +			buffer[i * 4 + j] = value >> (j * 8);
> >> +	}
> >> +
> >> +	return size;
> >> +}
> >> +
> >> +static ssize_t dw_dp_aux_transfer(struct drm_dp_aux *aux,
> >> +				  struct drm_dp_aux_msg *msg)
> >> +{
> >> +	struct dw_dp *dp = container_of(aux, struct dw_dp, aux);
> >> +	unsigned long timeout = msecs_to_jiffies(10);
> >> +	u32 status, value;
> >> +	ssize_t ret = 0;
> >> +
> >> +	if (WARN_ON(msg->size > 16))
> >> +		return -E2BIG;
> >> +
> >> +	switch (msg->request & ~DP_AUX_I2C_MOT) {
> >> +	case DP_AUX_NATIVE_WRITE:
> >> +	case DP_AUX_I2C_WRITE:
> >> +	case DP_AUX_I2C_WRITE_STATUS_UPDATE:
> >> +		ret = dw_dp_aux_write_data(dp, msg->buffer, msg->size);
> >> +		if (ret < 0)
> >> +			return ret;
> >> +		break;
> >> +	case DP_AUX_NATIVE_READ:
> >> +	case DP_AUX_I2C_READ:
> >> +		break;
> >> +	default:
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	if (msg->size > 0)
> >> +		value = FIELD_PREP(AUX_LEN_REQ, msg->size - 1);
> >> +	else
> >> +		value = FIELD_PREP(I2C_ADDR_ONLY, 1);
> >> +	value |= FIELD_PREP(AUX_CMD_TYPE, msg->request);
> >> +	value |= FIELD_PREP(AUX_ADDR, msg->address);
> >> +	regmap_write(dp->regmap, DW_DP_AUX_CMD, value);
> >> +
> >> +	status = wait_for_completion_timeout(&dp->complete, timeout);
> >> +	if (!status) {
> >> +		dev_err(dp->dev, "timeout waiting for AUX reply\n");
> >> +		return -ETIMEDOUT;
> >> +	}
> >> +
> >> +	regmap_read(dp->regmap, DW_DP_AUX_STATUS, &value);
> >> +	if (value & AUX_TIMEOUT)
> >> +		return -ETIMEDOUT;
> >> +
> >> +	msg->reply = FIELD_GET(AUX_STATUS, value);
> >> +
> >> +	if (msg->size > 0 && msg->reply == DP_AUX_NATIVE_REPLY_ACK) {
> >> +		if (msg->request & DP_AUX_I2C_READ) {
> >> +			size_t count = FIELD_GET(AUX_BYTES_READ, value) - 1;
> >> +
> >> +			if (count != msg->size)
> >> +				return -EBUSY;
> >> +
> >> +			ret = dw_dp_aux_read_data(dp, msg->buffer, count);
> >> +			if (ret < 0)
> >> +				return ret;
> >> +		}
> >> +	}
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +/*
> >> + * Limits for the video timing output by DP:
> >> + * 1. the hfp should be 2 pixels aligned;
> >> + * 2. the minimum hsync should be 9 pixel;
> >> + * 3. the minimum hbp should be 16 pixel;
> >> + */
> >> +static bool dw_dp_bridge_mode_fixup(struct drm_bridge *bridge,
> >> +				    const struct drm_display_mode *mode,
> >> +				    struct drm_display_mode *adjusted_mode)
> >> +{
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +	int min_hbp = 16;
> >> +	int min_hsync = 9;
> >> +
> >> +	if ((adjusted_mode->hsync_start - adjusted_mode->hdisplay) & 0x1) {
> >> +		adjusted_mode->hsync_start += 1;
> >> +		dev_warn(dp->dev, "hfp is not 2 pixeel aligned, fixup to aligned hfp\n");
> >> +	}
> >> +	if (adjusted_mode->hsync_end - adjusted_mode->hsync_start < min_hsync) {
> >> +		adjusted_mode->hsync_end = adjusted_mode->hsync_start + min_hsync;
> >> +		dev_warn(dp->dev, "hsync is too narrow, fixup to min hsync:%d\n", min_hsync);
> >> +	}
> >> +	if (adjusted_mode->htotal - adjusted_mode->hsync_end < min_hbp) {
> >> +		adjusted_mode->htotal = adjusted_mode->hsync_end + min_hbp;
> >> +		dev_warn(dp->dev, "hbp is too narrow, fixup to min hbp:%d\n", min_hbp);
> >> +	}
> >> +
> >> +	return true;
> >> +}
> >> +
> >> +static enum drm_mode_status dw_dp_bridge_mode_valid(struct drm_bridge *bridge,
> >> +						    const struct drm_display_info *info,
> >> +						    const struct drm_display_mode *mode)
> >> +{
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	u32 min_bpp;
> >> +
> >> +	if (info->color_formats & DRM_COLOR_FORMAT_YCBCR420 &&
> >> +	    link->vsc_sdp_supported &&
> >> +	    (drm_mode_is_420_only(info, mode) || drm_mode_is_420_also(info, mode)))
> >> +		min_bpp = 12;
> >> +	else if (info->color_formats & DRM_COLOR_FORMAT_YCBCR422)
> >> +		min_bpp = 16;
> >> +	else if (info->color_formats & DRM_COLOR_FORMAT_RGB444)
> >> +		min_bpp = 18;
> >> +	else
> >> +		min_bpp = 24;
> >> +
> >> +	if (!link->vsc_sdp_supported &&
> >> +	    drm_mode_is_420_only(info, mode))
> >> +		return MODE_NO_420;
> >> +
> >> +	if (!dw_dp_bandwidth_ok(dp, mode, min_bpp, link->lanes, link->rate))
> >> +		return MODE_CLOCK_HIGH;
> >> +
> >> +	return MODE_OK;
> >> +}
> >> +
> >> +static void dw_dp_bridge_atomic_pre_enable(struct drm_bridge *bridge,
> >> +					   struct drm_bridge_state *old_bridge_state)
> >> +{
> >> +	struct drm_atomic_state *state = old_bridge_state->base.state;
> >> +	struct drm_crtc_state *crtc_state = bridge->encoder->crtc->state;
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +	struct dw_dp_video *video = &dp->video;
> >> +	struct drm_display_mode *m = &video->mode;
> >> +	struct drm_bridge_state *bridge_state;
> >> +	const struct dw_dp_output_format *fmt;
> >> +
> >> +	drm_mode_copy(m, &crtc_state->adjusted_mode);
> >> +
> >> +	bridge_state = drm_atomic_get_new_bridge_state(state, bridge);
> >> +	fmt = dw_dp_get_output_format(bridge_state->output_bus_cfg.format);
> >
> >Should it be a part of the atomic_check() instead?
> 
> Since we have modef_fixup in this driver, which is mutually exclusive with atomic_check.

You can convet .mode_fixup into .atomic_check. The latter can change the
crtc_state->adjusted_mode. It is better to reject the invalid
combinations from the .atomic_check rather than having to handled them
later.

> 
> 
> 
> >
> >> +
> >> +	video->video_mapping = fmt->video_mapping;
> >> +	video->color_format = fmt->color_format;
> >> +	video->bpc = fmt->bpc;
> >> +	video->bpp = fmt->bpp;
> >> +}
> >> +
> >> +static bool dw_dp_needs_link_retrain(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	u8 link_status[DP_LINK_STATUS_SIZE];
> >> +
> >> +	if (!dw_dp_link_train_valid(&link->train))
> >> +		return false;
> >> +
> >> +	if (drm_dp_dpcd_read_link_status(&dp->aux, link_status) < 0)
> >> +		return false;
> >> +
> >> +	/* Retrain if Channel EQ or CR not ok */
> >> +	return !drm_dp_channel_eq_ok(link_status, dp->link.lanes);
> >> +}
> >> +
> >> +static void dw_dp_link_disable(struct dw_dp *dp)
> >> +{
> >> +	struct dw_dp_link *link = &dp->link;
> >> +
> >> +	if (dw_dp_hpd_detect(dp))
> >> +		dw_dp_link_power_down(dp);
> >> +
> >> +	dw_dp_phy_xmit_enable(dp, 0);
> >> +
> >> +	phy_power_off(dp->phy);
> >> +
> >> +	link->train.clock_recovered = false;
> >> +	link->train.channel_equalized = false;
> >> +}
> >> +
> >> +static int dw_dp_link_enable(struct dw_dp *dp)
> >> +{
> >> +	int ret;
> >> +
> >> +	ret = phy_power_on(dp->phy);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = dw_dp_link_power_up(dp);
> >> +	if (ret < 0)
> >> +		return ret;
> >> +
> >> +	ret = dw_dp_link_train(dp);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static void dw_dp_bridge_atomic_enable(struct drm_bridge *bridge,
> >> +				       struct drm_bridge_state *old_state)
> >> +{
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +	struct drm_atomic_state *state = old_state->base.state;
> >> +	struct drm_connector *connector;
> >> +	struct drm_connector_state *conn_state;
> >> +	int ret;
> >> +
> >> +	connector = drm_atomic_get_new_connector_for_encoder(state, bridge->encoder);
> >> +	if (!connector) {
> >> +		dev_err(dp->dev, "failed to get connector\n");
> >> +		return;
> >> +	}
> >> +
> >> +	conn_state = drm_atomic_get_new_connector_state(state, connector);
> >> +	if (!conn_state) {
> >> +		dev_err(dp->dev, "failed to get connector state\n");
> >> +		return;
> >> +	}
> >> +
> >> +	set_bit(0, dp->sdp_reg_bank);
> >> +
> >> +	ret = dw_dp_link_enable(dp);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "failed to enable link: %d\n", ret);
> >> +		return;
> >> +	}
> >> +
> >> +	ret = dw_dp_video_enable(dp);
> >> +	if (ret < 0) {
> >> +		dev_err(dp->dev, "failed to enable video: %d\n", ret);
> >> +		return;
> >> +	}
> >> +}
> >> +
> >> +static void dw_dp_reset(struct dw_dp *dp)
> >> +{
> >> +	int val;
> >> +
> >> +	disable_irq(dp->irq);
> >> +	regmap_update_bits(dp->regmap, DW_DP_SOFT_RESET_CTRL, CONTROLLER_RESET,
> >> +			   FIELD_PREP(CONTROLLER_RESET, 1));
> >> +	udelay(10);
> >> +	regmap_update_bits(dp->regmap, DW_DP_SOFT_RESET_CTRL, CONTROLLER_RESET,
> >> +			   FIELD_PREP(CONTROLLER_RESET, 0));
> >> +
> >> +	dw_dp_init_hw(dp);
> >> +	regmap_read_poll_timeout(dp->regmap, DW_DP_HPD_STATUS, val,
> >> +				 FIELD_GET(HPD_HOT_PLUG, val), 200, 200000);
> >> +	regmap_write(dp->regmap, DW_DP_HPD_STATUS, HPD_HOT_PLUG);
> >> +	enable_irq(dp->irq);
> >> +}
> >> +
> >> +static void dw_dp_bridge_atomic_disable(struct drm_bridge *bridge,
> >> +					struct drm_bridge_state *old_bridge_state)
> >> +{
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +
> >> +	dw_dp_video_disable(dp);
> >> +	dw_dp_link_disable(dp);
> >> +	bitmap_zero(dp->sdp_reg_bank, SDP_REG_BANK_SIZE);
> >> +	dw_dp_reset(dp);
> >> +}
> >> +
> >> +static bool dw_dp_hpd_detect_link(struct dw_dp *dp)
> >> +{
> >> +	int ret;
> >> +
> >> +	ret = phy_power_on(dp->phy);
> >> +	if (ret < 0)
> >> +		return false;
> >> +	ret = dw_dp_link_parse(dp);
> >> +	phy_power_off(dp->phy);
> >> +
> >> +	return !ret;
> >> +}
> >> +
> >> +static enum drm_connector_status dw_dp_bridge_detect(struct drm_bridge *bridge)
> >> +{
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +
> >> +	if (!dw_dp_hpd_detect(dp))
> >> +		return connector_status_disconnected;
> >> +
> >> +	if (!dw_dp_hpd_detect_link(dp))
> >> +		return connector_status_disconnected;
> >> +
> >> +	return connector_status_connected;
> >> +}
> >> +
> >> +static const struct drm_edid *dw_dp_bridge_edid_read(struct drm_bridge *bridge,
> >> +						     struct drm_connector *connector)
> >> +{
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +	const struct drm_edid *edid;
> >> +	int ret;
> >> +
> >> +	ret = phy_power_on(dp->phy);
> >> +	if (ret)
> >> +		return NULL;
> >> +
> >> +	edid = drm_edid_read_ddc(connector, &dp->aux.ddc);
> >> +
> >> +	phy_power_off(dp->phy);
> >> +
> >> +	return edid;
> >> +}
> >> +
> >> +static u32 *dw_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)
> >> +{
> >> +	struct dw_dp *dp = bridge_to_dp(bridge);
> >> +	struct dw_dp_link *link = &dp->link;
> >> +	struct drm_display_info *di = &conn_state->connector->display_info;
> >> +	struct drm_display_mode mode = crtc_state->mode;
> >> +	const struct dw_dp_output_format *fmt;
> >> +	u32 i, j = 0;
> >> +	u32 *output_fmts;
> >> +
> >> +	*num_output_fmts = 0;
> >> +
> >> +	output_fmts = kcalloc(ARRAY_SIZE(dw_dp_output_formats), sizeof(*output_fmts), GFP_KERNEL);
> >> +	if (!output_fmts)
> >> +		return NULL;
> >> +
> >> +	for (i = 0; i < ARRAY_SIZE(dw_dp_output_formats); i++) {
> >> +		fmt = &dw_dp_output_formats[i];
> >> +
> >> +		if (fmt->bpc > conn_state->max_bpc)
> >> +			continue;
> >> +
> >> +		if (!(fmt->color_format & di->color_formats))
> >> +			continue;
> >> +
> >> +		if (fmt->color_format == DRM_COLOR_FORMAT_YCBCR420 &&
> >> +		    !link->vsc_sdp_supported)
> >> +			continue;
> >> +
> >> +		if (fmt->color_format != DRM_COLOR_FORMAT_YCBCR420 &&
> >> +		    drm_mode_is_420_only(di, &mode))
> >> +			continue;
> >> +
> >> +		if (!dw_dp_bandwidth_ok(dp, &mode, fmt->bpp, link->lanes, link->rate))
> >> +			continue;
> >> +
> >> +		output_fmts[j++] = fmt->bus_format;
> >> +	}
> >> +
> >> +	*num_output_fmts = j;
> >> +
> >> +	return output_fmts;
> >> +}
> >> +
> >> +static const struct drm_bridge_funcs dw_dp_bridge_funcs = {
> >> +	.atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> >> +	.atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> >> +	.atomic_reset = drm_atomic_helper_bridge_reset,
> >> +	.atomic_get_input_bus_fmts = drm_atomic_helper_bridge_propagate_bus_fmt,
> >> +	.atomic_get_output_bus_fmts = dw_dp_bridge_atomic_get_output_bus_fmts,
> >> +	.mode_fixup = dw_dp_bridge_mode_fixup,
> >> +	.mode_valid = dw_dp_bridge_mode_valid,
> >> +	.atomic_pre_enable = dw_dp_bridge_atomic_pre_enable,
> >> +	.atomic_enable = dw_dp_bridge_atomic_enable,
> >> +	.atomic_disable = dw_dp_bridge_atomic_disable,
> >> +	.detect = dw_dp_bridge_detect,
> >> +	.edid_read = dw_dp_bridge_edid_read,
> >> +};
> >> +
> >> +static int dw_dp_link_retrain(struct dw_dp *dp)
> >> +{
> >> +	struct drm_device *dev = dp->bridge.dev;
> >> +	struct drm_modeset_acquire_ctx ctx;
> >> +	int ret;
> >> +
> >> +	if (!dw_dp_needs_link_retrain(dp))
> >> +		return 0;
> >> +
> >> +	dev_dbg(dp->dev, "Retraining link\n");
> >> +
> >> +	drm_modeset_acquire_init(&ctx, 0);
> >> +	for (;;) {
> >> +		ret = drm_modeset_lock(&dev->mode_config.connection_mutex, &ctx);
> >> +		if (ret != -EDEADLK)
> >> +			break;
> >
> >I think it's an error to continue in such a case. There should be a
> >return after the loop if ret is not 0.
> 
> Thank you for catching this, I will add a check fater the loop.
> 
> 
> >
> >> +
> >> +		drm_modeset_backoff(&ctx);
> >> +	}
> >> +
> >> +	ret = dw_dp_link_train(dp);
> >> +	drm_modeset_drop_locks(&ctx);
> >> +	drm_modeset_acquire_fini(&ctx);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static void dw_dp_hpd_work(struct work_struct *work)
> >> +{
> >> +	struct dw_dp *dp = container_of(work, struct dw_dp, hpd_work);
> >> +	bool long_hpd;
> >> +	int ret;
> >> +
> >> +	mutex_lock(&dp->irq_lock);
> >> +	long_hpd = dp->hotplug.long_hpd;
> >> +	mutex_unlock(&dp->irq_lock);
> >> +
> >> +	dev_dbg(dp->dev, "[drm] Get hpd irq - %s\n", long_hpd ? "long" : "short");
> >> +
> >> +	if (!long_hpd) {
> >> +		if (dw_dp_needs_link_retrain(dp)) {
> >> +			ret = dw_dp_link_retrain(dp);
> >> +			if (ret)
> >> +				dev_warn(dp->dev, "Retrain link failed\n");
> >> +		}
> >> +	} else {
> >> +		drm_helper_hpd_irq_event(dp->bridge.dev);
> >> +	}
> >> +}
> >> +
> >> +static void dw_dp_handle_hpd_event(struct dw_dp *dp)
> >> +{
> >> +	u32 value;
> >> +
> >> +	mutex_lock(&dp->irq_lock);
> >> +	regmap_read(dp->regmap, DW_DP_HPD_STATUS, &value);
> >> +
> >> +	if (value & HPD_IRQ) {
> >> +		dev_dbg(dp->dev, "IRQ from the HPD\n");
> >> +		dp->hotplug.long_hpd = false;
> >> +		regmap_write(dp->regmap, DW_DP_HPD_STATUS, HPD_IRQ);
> >> +	}
> >> +
> >> +	if (value & HPD_HOT_PLUG) {
> >> +		dev_dbg(dp->dev, "Hot plug detected\n");
> >> +		dp->hotplug.long_hpd = true;
> >> +		regmap_write(dp->regmap, DW_DP_HPD_STATUS, HPD_HOT_PLUG);
> >> +	}
> >> +
> >> +	if (value & HPD_HOT_UNPLUG) {
> >> +		dev_dbg(dp->dev, "Unplug detected\n");
> >> +		dp->hotplug.long_hpd = true;
> >> +		regmap_write(dp->regmap, DW_DP_HPD_STATUS, HPD_HOT_UNPLUG);
> >> +	}
> >> +	mutex_unlock(&dp->irq_lock);
> >> +
> >> +	schedule_work(&dp->hpd_work);
> >> +}
> >> +
> >> +static irqreturn_t dw_dp_irq(int irq, void *data)
> >> +{
> >> +	struct dw_dp *dp = data;
> >> +	u32 value;
> >> +
> >> +	regmap_read(dp->regmap, DW_DP_GENERAL_INTERRUPT, &value);
> >> +	if (!value)
> >> +		return IRQ_NONE;
> >> +
> >> +	if (value & HPD_EVENT)
> >> +		dw_dp_handle_hpd_event(dp);
> >> +
> >> +	if (value & AUX_REPLY_EVENT) {
> >> +		regmap_write(dp->regmap, DW_DP_GENERAL_INTERRUPT, AUX_REPLY_EVENT);
> >> +		complete(&dp->complete);
> >> +	}
> >> +
> >> +	return IRQ_HANDLED;
> >> +}
> >> +
> >> +static const struct regmap_range dw_dp_readable_ranges[] = {
> >> +	regmap_reg_range(DW_DP_VERSION_NUMBER, DW_DP_ID),
> >> +	regmap_reg_range(DW_DP_CONFIG_REG1, DW_DP_CONFIG_REG3),
> >> +	regmap_reg_range(DW_DP_CCTL, DW_DP_SOFT_RESET_CTRL),
> >> +	regmap_reg_range(DW_DP_VSAMPLE_CTRL, DW_DP_VIDEO_HBLANK_INTERVAL),
> >> +	regmap_reg_range(DW_DP_AUD_CONFIG1, DW_DP_AUD_CONFIG1),
> >> +	regmap_reg_range(DW_DP_SDP_VERTICAL_CTRL, DW_DP_SDP_STATUS_EN),
> >> +	regmap_reg_range(DW_DP_PHYIF_CTRL, DW_DP_PHYIF_PWRDOWN_CTRL),
> >> +	regmap_reg_range(DW_DP_AUX_CMD, DW_DP_AUX_DATA3),
> >> +	regmap_reg_range(DW_DP_GENERAL_INTERRUPT, DW_DP_HPD_INTERRUPT_ENABLE),
> >> +};
> >> +
> >> +static const struct regmap_access_table dw_dp_readable_table = {
> >> +	.yes_ranges     = dw_dp_readable_ranges,
> >> +	.n_yes_ranges   = ARRAY_SIZE(dw_dp_readable_ranges),
> >> +};
> >> +
> >> +static const struct regmap_config dw_dp_regmap_config = {
> >> +	.reg_bits = 32,
> >> +	.reg_stride = 4,
> >> +	.val_bits = 32,
> >> +	.fast_io = true,
> >> +	.max_register = DW_DP_MAX_REGISTER,
> >> +	.rd_table = &dw_dp_readable_table,
> >> +};
> >> +
> >> +struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
> >> +			 const struct dw_dp_plat_data *plat_data)
> >> +{
> >> +	struct platform_device *pdev = to_platform_device(dev);
> >> +	struct dw_dp *dp;
> >> +	struct drm_bridge *bridge;
> >> +	void __iomem *res;
> >> +	int ret;
> >> +
> >> +	dp = devm_kzalloc(dev, sizeof(*dp), GFP_KERNEL);
> >> +	if (!dp)
> >> +		return ERR_PTR(-ENOMEM);
> >> +
> >> +	dp->dev = dev;
> >> +	dp->video.pixel_mode = DW_DP_MP_QUAD_PIXEL;
> >> +
> >> +	dp->plat_data = plat_data;
> >> +	bridge = &dp->bridge;
> >> +	mutex_init(&dp->irq_lock);
> >> +	INIT_WORK(&dp->hpd_work, dw_dp_hpd_work);
> >> +	init_completion(&dp->complete);
> >> +
> >> +	res = devm_platform_ioremap_resource(pdev, 0);
> >> +	if (IS_ERR(res))
> >> +		return ERR_CAST(res);
> >> +
> >> +	dp->regmap = devm_regmap_init_mmio(dev, res, &dw_dp_regmap_config);
> >> +	if (IS_ERR(dp->regmap)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->regmap), "failed to create regmap\n");
> >> +		return ERR_CAST(dp->regmap);
> >> +	}
> >> +
> >> +	dp->phy = devm_of_phy_get(dev, dev->of_node, NULL);
> >> +	if (IS_ERR(dp->phy)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->phy), "failed to get phy\n");
> >> +		return ERR_CAST(dp->phy);
> >> +	}
> >> +
> >> +	dp->apb_clk = devm_clk_get_enabled(dev, "apb");
> >> +	if (IS_ERR(dp->apb_clk)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->apb_clk), "failed to get apb clock\n");
> >> +		return ERR_CAST(dp->apb_clk);
> >> +	}
> >> +
> >> +	dp->aux_clk = devm_clk_get_enabled(dev, "aux");
> >> +	if (IS_ERR(dp->aux_clk)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->aux_clk), "failed to get aux clock\n");
> >> +		return ERR_CAST(dp->aux_clk);
> >> +	}
> >> +
> >> +	dp->i2s_clk = devm_clk_get(dev, "i2s");
> >> +	if (IS_ERR(dp->i2s_clk)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->i2s_clk), "failed to get i2s clock\n");
> >> +		return ERR_CAST(dp->i2s_clk);
> >> +	}
> >> +
> >> +	dp->spdif_clk = devm_clk_get(dev, "spdif");
> >> +	if (IS_ERR(dp->spdif_clk)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->spdif_clk), "failed to get spdif clock\n");
> >> +		return ERR_CAST(dp->spdif_clk);
> >> +	}
> >> +
> >> +	dp->hdcp_clk = devm_clk_get(dev, "hdcp");
> >> +	if (IS_ERR(dp->hdcp_clk)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->hdcp_clk), "failed to get hdcp clock\n");
> >> +		return ERR_CAST(dp->hdcp_clk);
> >> +	}
> >> +
> >> +	dp->rstc = devm_reset_control_get(dev, NULL);
> >> +	if (IS_ERR(dp->rstc)) {
> >> +		dev_err_probe(dev, PTR_ERR(dp->rstc), "failed to get reset control\n");
> >> +		return ERR_CAST(dp->rstc);
> >> +	}
> >> +
> >> +	dp->irq = platform_get_irq(pdev, 0);
> >> +	if (dp->irq < 0)
> >> +		return ERR_PTR(ret);
> >> +
> >> +	ret = devm_request_threaded_irq(dev, dp->irq, NULL, dw_dp_irq,
> >> +					IRQF_ONESHOT, dev_name(dev), dp);
> >
> >Are you ready to handle the IRQ here, before the bridge is filled?
> 
> I will move to  devm_request_threaded_irq after dw_dp_init_hw.
> 
> 
> >
> >> +	if (ret) {
> >> +		dev_err_probe(dev, ret, "failed to request irq\n");
> >> +		return ERR_PTR(ret);
> >> +	}
> >> +
> >> +	bridge->of_node = dev->of_node;
> >> +	bridge->funcs = &dw_dp_bridge_funcs;
> >> +	bridge->ops = DRM_BRIDGE_OP_DETECT | DRM_BRIDGE_OP_EDID | DRM_BRIDGE_OP_HPD;
> >> +	bridge->type = DRM_MODE_CONNECTOR_DisplayPort;
> >> +	bridge->ycbcr_420_allowed = true;
> >> +	bridge->vendor = "Synopsys";
> >> +	bridge->product = "DW DP TX";
> >
> >These two are unused
> >
> >> +
> >> +	platform_set_drvdata(pdev, dp);
> >
> >Unused
> 
> I will remove them.
> 
> Thanks again.
> 
> 
> >
> >> +
> >> +	dp->aux.dev = dev;
> >> +	dp->aux.drm_dev = encoder->dev;
> >> +	dp->aux.name = dev_name(dev);
> >> +	dp->aux.transfer = dw_dp_aux_transfer;
> >> +	ret = drm_dp_aux_register(&dp->aux);
> >> +	if (ret) {
> >> +		dev_err_probe(dev, ret, "Aux register failed\n");
> >> +		return ERR_PTR(ret);
> >> +	}
> >> +
> >> +	ret = drm_bridge_attach(encoder, bridge, NULL, DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> >> +	if (ret)
> >> +		dev_err_probe(dev, ret, "Failed to attach bridge\n");
> >> +
> >> +	dw_dp_init_hw(dp);
> >> +
> >> +	return dp;
> >> +}
> >> +MODULE_AUTHOR("Andy Yan <andyshrk@xxxxxxx>");
> >> +MODULE_DESCRIPTION("DW DP Core Library");
> >> +MODULE_LICENSE("GPL");
> >> diff --git a/include/drm/bridge/dw_dp.h b/include/drm/bridge/dw_dp.h
> >> new file mode 100644
> >> index 000000000000..07845f609eca
> >> --- /dev/null
> >> +++ b/include/drm/bridge/dw_dp.h
> >> @@ -0,0 +1,19 @@
> >> +/* SPDX-License-Identifier: GPL-2.0-or-later */
> >> +/*
> >> + * Copyright (c) 2025 Rockchip Electronics Co., Ltd.
> >> + */
> >> +
> >> +#ifndef __DW_DP__
> >> +#define __DW_DP__
> >> +
> >> +struct device;
> >> +struct drm_encoder;
> >> +struct dw_dp;
> >> +
> >> +struct dw_dp_plat_data {
> >> +	u32 max_link_rate;
> >> +};
> >> +
> >> +struct dw_dp *dw_dp_bind(struct device *dev, struct drm_encoder *encoder,
> >> +			 const struct dw_dp_plat_data *plat_data);
> >> +#endif /* __DW_DP__ */
> >> -- 
> >> 2.34.1
> >> 
> >
> >-- 
> >With best wishes
> >Dmitry

-- 
With best wishes
Dmitry



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