[参考译文] SN65DSI86：TI SN65DSI86至 eDP 面板(NT156FHM-N41)-与 raspberrypi 计算模块4 (6.6.y Linux 内核)无 AUX 通信

您好 Bhavin、

您是否在启动事务时探测并观察到 AUX 信道上的活动？ 请检查波形以确认辅助通道上存在活动。

请查看数据表中 I2C over AUX 的直接和间接方法："8.4.5.3 I2C-over-AUX"一节。 您使用哪种方法？  您能否共享脚本以了解如何启动这些步骤？  

您的系统使用哪种 DP 链路训练模式？ AUX 是否在您设置的模式下用于链路训练？

此致、
Ikram

尚未开始、我们想先确认我们的软件配置。 进行探测。

是的、我们在测试脚本中遵循间接方法。 我将在下面添加脚本

EDID_read2.sh
 

#!/bin/bash

I2C_DEV=1
BRIDGE_ADDR=0x2c

# 1. Enable EDID I2C address claim (0x50 with enable bit)
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x60 0x61 #0xA1  # 0xA1 = 0b10100001

# 2. Set AUX_ADDR for I2C-over-AUX EDID address (high/mid = 0)
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x74 0x00  # AUX_ADDR[19:16]
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x75 0x00  # AUX_ADDR[15:8]
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x76 0x30 #0x50  # AUX_ADDR[7:0] — EDID address

# 3. Set length to 16 bytes (0x10) — can read full EDID by looping
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x77 0x10

# 4. Set command to I2C read (0x09 = I2C-over-AUX Read Request)
#     Format: (CMD << 4) | 0x01 = 0x91
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x78 0x91

# 5. Poll until SEND bit (bit 0 of 0x78) is cleared (max timeout 1s)
timeout_ms=1000
elapsed=0
while true; do
    val=$(i2cget -y -f $I2C_DEV $BRIDGE_ADDR 0x78)
    if (( (val & 0x01) == 0 )); then
        break
    fi
    sleep 0.01
    elapsed=$((elapsed + 10))
    if (( elapsed >= timeout_ms )); then
        echo "ERROR: AUX transaction timed out"
        exit 1
    fi
done

# 6. Read back data (AUX_RDATA0 - AUX_RDATA15)
echo "EDID chunk (16 bytes):"
for i in $(seq 0 15); do
    reg=$((0x79 + i))
    byte=$(i2cget -y -f $I2C_DEV $BRIDGE_ADDR $reg)
    printf "%s " "$byte"
done
echo

#!/bin/bash

I2C_DEV=1        # Replace with correct I2C bus
BRIDGE_ADDR=0x2c           # SN65DSI86 I2C address
EDID_ADDR=0x50             # Standard EDID I2C address
NUM_BLOCKS=1               # EDID block count (1 = 128 bytes)
BYTES_PER_BLOCK=128

# Enable I2C Claim1 for EDID address (0x50)
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x60 $((EDID_ADDR << 1 | 1)) # 7:1 address + EN bit

# Function to read EDID block (16 bytes at a time)
read_block() {
    local offset=$1
    for ((i=0; i<BYTES_PER_BLOCK; i+=16)); do
        # Set AUX_ADDR[7:0] to EDID address (0x50)
        i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x77 $EDID_ADDR

        # Set AUX_LENGTH (0x74) to 16
        i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x74 0x10

        # Set AUX_CMD (0x78) to 0x9 (I2C Read)
        # Set SEND bit (bit 0) to trigger transaction
        i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x78 0x91

        # Poll until SEND bit clears
        while true; do
            val=$(i2cget -y -f $I2C_DEV $BRIDGE_ADDR 0x78)
            if (( val & 0x01 == 0 )); then
                break
            fi
            printf "Poll until SEND  bit clears"
            sleep 0.01
        done

        # Read 16 bytes from AUX_RDATA0–15 (0x79 to 0x88)
        printf "EDID offset 0x%02X: " $((offset + i))
        for ((j=0; j<16; j++)); do
            byte=$(i2cget -y -f $I2C_DEV $BRIDGE_ADDR $((0x79 + j)))
            printf "%s " "$byte"
        done
        echo
    done
}

# Read full EDID
for ((block=0; block<NUM_BLOCKS; block++)); do
    read_block $((block * BYTES_PER_BLOCK))
done

#!/bin/bash

I2C_DEV=1               # Replace with correct I2C bus (e.g., /dev/i2c-2)
BRIDGE_ADDR=0x2c        # SN65DSI86 I2C address
DPCD_ADDR=(0x00 0x00 0x00)  # DPCD base address is 0x00000

# Write DPCD address to AUX_ADDR registers (0x74, 0x75, 0x76)
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x74 ${DPCD_ADDR[0]} b
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x75 ${DPCD_ADDR[1]} b
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x76 ${DPCD_ADDR[2]} b

# Set AUX length to 16 bytes
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x77 0x10 b

# Set AUX_CMD to 0x2 (AUX read)
# Set SEND = 1 to initiate transaction
i2cset -y -f $I2C_DEV $BRIDGE_ADDR 0x78 0x21 b

# Poll until SEND bit clears
for i in {1..100}; do
    val=$(i2cget -y -f $I2C_DEV $BRIDGE_ADDR 0x78)
    if (( (val & 0x01) == 0 )); then
        break
    fi
    sleep 0.01
done

# Check if it timed out
if (( (val & 0x01) != 0 )); then
    echo "Timeout waiting for AUX transaction to complete."
    exit 1
fi

# Read back 16 bytes from AUX_RDATA0–AUX_RDATA15 (0x79–0x88)
echo "DPCD Response:"
for ((i=0; i<16; i++)); do
    reg=$((0x79 + i))
    data=$(i2cget -y -f $I2C_DEV $BRIDGE_ADDR $reg)
    printf "0x%02x " $data
done
echo

#!/bin/bash

I2CBUS=1        # Adjust as per your I2C bus
ADDR=0x2c       # SN65DSI86 I2C address

if [ $# -gt 0 ]; then
	ASSR=1
else
	ASSR=0
fi

echo "ASSR:$ASSR"

raspi-gpio set 20 op dl
sleep 1
raspi-gpio set 20 op dh

# Helper to write a register
w() {
  i2cset -y $I2CBUS $ADDR $1 $2
}

echo "[INFO] Configuring SN65DSI86 for test pattern..."
if [ "$ASSR" -eq 0 ]; then
	echo "configuring Non ASSR"
	w 0xff 0x07
	w 0x16 0x01
	w 0xff 0x00    
fi

# Configure REFCLK 27 MHz
w 0x0a 0x06

# DSI A 4 Lanes
w 0x10 0x20

#DSIA Freq 445MHz
w 0x12 0x59

if [ "$ASSR" -eq 1 ]; then
	w 0x5a 0x05
else
	#Enhance framing NO ASSR
	w 0x5a 0x04
fi

#DP link rate 2.7 Gbps
w 0x94 0x80

# DP Lanes 2, no SSC
w 0x93 0x20

# Enable PLL
w 0x0d 0x01
sleep 0.1

if [ "$ASSR" -eq 1 ]; then
	echo "configuring ASSR"
	w 0x95 0x00
	w 0x64 0x01
	w 0x74 0x00
	w 0x75 0x01
	w 0x76 0x0a
	w 0x77 0x01
	w 0x78 0x81
	sleep 0.10
fi

# Semi auto train
w 0x96 0x0a
sleep 0.2

# Video Parameters
# Horizontal active: 1920
w 0x21 $(( (1920 >> 8) & 0xFF ))
w 0x20 $(( 1920 & 0xFF ))

# Vertical active: 1080
w 0x25 $(( (1080 >> 8) & 0xFF ))
w 0x24 $(( 1080 & 0xFF ))

# Horizontal front porch and back porch
w 0x38 207
w 0x34 48

# HSync width: 32
w 0x2c 32

# vertical front porch and back porch
w 0x3a 71
w 0x36 3

# VSync width: 6
w 0x30 6

# Dp 24 bpp
w 0x5b 0x00

# Color Bar enable
w 0x3c 0x14 #12 = 3 color working

# enhanced framing, ASSR, and Vstream enable
w 0x5a 0x0d

echo "[DONE] Test pattern should now be visible on the panel."

尊敬的 Bhavin：

1.我不熟悉您分享的驱动程序代码。 您能告诉我们您从哪里得到这个吗？

我们为该器件提供的软件是：

DSI 驱动程序代码： https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/bridge/ti-sn65dsi86.c

DSI 寄存器计算器： https://e2e.ti.com/support/interface-group/interface/f/interface-forum/945404/faq-sn65dsi86-how-do-i-programming-the-sn65dsi86-registers?tisearch=e2e-sitesearch&keymatch=sn65dsi86#

您也可以使用上面的计算器工具输入配置并生成用于初始化的 I2C 脚本。

2.有关 I2C over aux 步骤、请给我1-2天时间检查您共享的"EDID_READ"脚本、并将其与数据表匹配。

让我知道您是否能够探测和检查 AUX 信道活动。 此外、您正在使用 TI EVM 来测试 DSI86器件、


此致、
Ikram

你好 Bhavin ,我将检查脚本,并得到你.

谢谢您、
Ikram

是否有任何更新？

尊敬的 Bhavin：

很抱歉耽误时间。 从"EDID_read2.sh"脚本中、似乎您将 AUX_ADDR 设置为0x30、而不是0x50。 这适用于您的应用吗？

此外、您要将0x78设置为0x91、而不是0x41。  您是否可以 将 AUX_CMD = 0x4用作"I2C-over-Aux Write MOT = 1"选项？

之前的 E2E 末尾包含一小部分代码： https://e2e.ti.com/support/interface-group/interface/f/interface-forum/957141/sn65dsi86-q1-i2c-detection-problem

此外、如果您的系统允许时钟延展、则您可以考虑使用直接方法来简化序列。

此致、
Ikram

尊敬的 Bhavin：

以下是之前有关直接方法的 E2E 主题： https://e2e.ti.com/support/interface-group/interface/f/interface-forum/949449/sn65dsi86-i2c-over-aux-direct-method/3508159

脚本语法来自 Aardvark I2C 适配器

谢谢您、
Ikram