USB

The Universal Serial Bus (USB) supports data exchange and power supply between electronic devices at speeds from 1.5 Mbps (low speed) up to 10 Gbps (SuperSpeed Plus). The IQ-8275 uses the Synopsys DesignWare Core SuperSpeed USB 3.x controller connected to USB2 PHY (UTMI) and USB3 PHY (PIPE) interfaces. The board features three USB connectors: two Type-C (USB0, USB1) and one micro-USB (USB2).

Controllers

Controller	Address	Max Speed
USB0	0xa600000	USB 3.x SuperSpeed
USB1	0xa800000	USB 3.x SuperSpeed
USB2	0xa400000	USB 2.0 High Speed

Features

Hardware Features

Feature	Description
Dual-Role Device (DRD)	Host and device modes with dynamic role detection
USB 3.1 Gen1	SuperSpeed 5 Gbps on USB0 and USB1
USB 2.0 High Speed	480 Mbps on all controllers
xHCI	eXtensible Host Controller Interface compliance
Transfer types	Control, bulk, interrupt, isochronous

Software Features

Peripheral mode: Mass Storage, Diagnostics (FunctionFS), RNDIS, NCM Host mode: xHCI, HID/MS/Hub class drivers, UVC (USB camera), Link Power Management

Configuration

Runtime Power Management

echo auto > /sys/bus/platform/devices/a600000.usb/power/control
echo 2000 > /sys/bus/platform/devices/a600000.usb/power/autosuspend_delay_ms
cat /sys/bus/platform/devices/a600000.usb/power/runtime_status

Prevent Suspend During Composition Switch

echo on > /sys/bus/platform/devices/a600000.usb/power/control
# Perform composition switch
echo auto > /sys/bus/platform/devices/a600000.usb/power/control

USB Camera

The IQ-8275 supports USB cameras that comply with the USB Video Class (UVC) standard via the uvcvideo kernel driver, exposing devices as /dev/videoX.

Detect the camera

lsusb
v4l2-ctl --list-devices
ls -l /dev/v4l/by-id/

Check supported formats

yavta /dev/video2 --enum-formats

Stream video

yavta
GStreamer

yavta -f MJPEG -s 1280x720 -t 1/30 -c10 -F/home/ubuntu/test.jpeg /dev/video2

export XDG_RUNTIME_DIR=/run/user/$(id -u ubuntu)
export WAYLAND_DISPLAY=wayland-1

gst-launch-1.0 -e v4l2src device=/dev/video2 ! \
  video/x-raw,format=YUY2,width=1280,height=720,framerate=30/1 ! \
  videoconvert ! waylandsink fullscreen=true

Verification

lsusb                              # List connected USB devices
cat /sys/kernel/debug/usb/devices  # Detailed device info
cat /sys/kernel/debug/usb/a600000.usb/mode        # Check USB mode
cat /sys/kernel/debug/usb/a600000.usb/link_state  # Check link state

Debugging

mount -t debugfs none /sys/kernel/debug
echo 1 > /sys/kernel/debug/tracing/events/dwc3/enable
echo 1 > /sys/kernel/debug/tracing/events/xhci-hcd/enable
cat /sys/kernel/debug/tracing/trace

Troubleshooting

USB Device Not Enumerated

cat /sys/kernel/debug/usb/a600000.usb/mode
cat /sys/kernel/debug/usb/a600000.usb/link_state
dmesg | grep -i usb

Rebind gadget: qusb unbind && qusb bind
Check cable connection and power rails

USB Camera Not Working

lsusb
ls /dev/video*
dmesg | grep -i uvc
lsmod | grep uvcvideo

Composition Switch Fails

echo on > /sys/bus/platform/devices/a600000.usb/power/control
qusb setpid <PID>
echo auto > /sys/bus/platform/devices/a600000.usb/power/control

IQ-8275 EVK

Controllers

Features

Hardware Features

Software Features

Configuration

Runtime Power Management

Prevent Suspend During Composition Switch

USB Camera

Verification

Debugging

Troubleshooting

Resources

​Controllers

​Features

​Hardware Features

​Software Features

​Configuration

​Runtime Power Management

​Prevent Suspend During Composition Switch

​USB Camera

​Verification

​Debugging

​Troubleshooting

​Resources

Controllers

Features

Hardware Features

Software Features

Configuration

Runtime Power Management

Prevent Suspend During Composition Switch

USB Camera

Verification

Debugging

Troubleshooting

Resources