Hi3521DV100 USB无法识别问题分析

Hi3521DV100偶现一块板子的USB无法识别，且内核打印：Cannot enable. Maybe the USB cable is bad?接下来分析原因。

驱动打印

ehci_hcd: USB 2.0 'Enhanced' Host Controller (EHCI) Driver
ehci-platform: EHCI generic platform driver
ehci-platform 10040000.ehci: EHCI Host Controller
ehci-platform 10040000.ehci: new USB bus registered, assigned bus number 1
ehci-platform 10040000.ehci: irq 51, io mem 0x10040000
ehci-platform 10040000.ehci: USB 2.0 started, EHCI 1.00
hub 1-0:1.0: USB hub found
hub 1-0:1.0: 2 ports detected
ohci_hcd: USB 1.1 'Open' Host Controller (OHCI) Driver
ohci-platform: OHCI generic platform driver
ohci-platform 10030000.ohci: Generic Platform OHCI controller
ohci-platform 10030000.ohci: new USB bus registered, assigned bus number 2
ohci-platform 10030000.ohci: irq 50, io mem 0x10030000
ata2: SATA link down (SStatus 0 SControl 300)
hub 2-0:1.0: USB hub found
hub 2-0:1.0: 2 ports detected
usbcore: registered new interface driver usb-storage
mousedev: PS/2 mouse device common for all mice
i2c /dev entries driver
hisi_i2c hisi_i2c.0: Hisilicon [i2c-0] probed!
usbcore: registered new interface driver usbhid
usbhid: USB HID core driver

usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb 2-2: new full-speed USB device number 47 using ohci-platform
usb usb2-port2: Cannot enable. Maybe the USB cable is bad?
usb 2-2: new full-speed USB device number 48 using ohci-platform
usb 2-2: device descriptor read/64, error -62
usb 2-2: device descriptor read/64, error -62
usb 2-2: new full-speed USB device number 49 using ohci-platform
usb 2-2: device not accepting address 49, error -62
usb 2-2: new full-speed USB device number 50 using ohci-platform
usb 2-2: device not accepting address 50, error -62
usb usb2-port2: unable to enumerate USB device

硬件设计

使用USB2口，D0做USB，D1做USB转SD卡。

问题现象

1、接U盘，U盘灯不亮，测量5V电源输出，手机插上能充电，排除电源问题；

2、不接外围设备，依然无反应，排除供电问题；

3、拆掉Z4 Z5 ESD器件，无改善，拍摄ESD问题；

4、查看电路图，发现LB14器件缺失导致的问题；

问题原因

分析电路图发现，供电AVDD33_USB的LB14器件缺失，怀疑是没有给CPU内部的USB供电导致的问题。

通过拆其他板子的器件替换后，USB和SD卡功能都正常了，打印如下：

SD卡：
scsi 2:0:0:0: Direct-Access     Generic  MassStorageClass 2402 PQ: 0 ANSI: 6
sd 2:0:0:0: [sda] 15523840 512-byte logical blocks: (7.94 GB/7.40 GiB)
sd 2:0:0:0: [sda] Write Protect is off
sd 2:0:0:0: [sda] Mode Sense: 21 00 00 00
sd 2:0:0:0: [sda] Write cache: disabled, read cache: enabled, doesn't support DPO or FUA
 sda: sda1
sd 2:0:0:0: [sda] Attached SCSI removable disk

U盘：
usb 1-1: new high-speed USB device number 3 using ehci-platform
usb-storage 1-1:1.0: USB Mass Storage device detected
usb-storage 1-1:1.0: Quirks match for vid 05e3 pid 0723: 8000
scsi host3: usb-storage 1-1:1.0
scsi 3:0:0:0: Direct-Access     Generic  STORAGE DEVICE   9451 PQ: 0 ANSI: 0
sd 3:0:0:0: [sdb] 15630336 512-byte logical blocks: (8.00 GB/7.45 GiB)
sd 3:0:0:0: [sdb] Write Protect is off
sd 3:0:0:0: [sdb] Mode Sense: 03 00 00 00
sd 3:0:0:0: [sdb] No Caching mode page found
sd 3:0:0:0: [sdb] Assuming drive cache: write through
 sdb: sdb4
sd 3:0:0:0: [sdb] Attached SCSI removable disk