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.barysh...@linaro.org> 写道:
> >On Sun, Feb 23, 2025 at 07:30:25PM +0800, Andy Yan wrote:
> >> From: Andy Yan <andy....@rock-chips.com>
> >> 
> >> 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....@rock-chips.com>
> >> 
> >> 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....@rock-chips.com>
> >> + */
> >> +#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-v4-4-7ecb07b09...@kernel.org/

> 
> >
> >> +}
> >> +
> >> +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 <andys...@163.com>");
> >> +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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