opkg update
opkg install kmod-usb-core kmod-usb2 kmod-video-core
opkg install kmod-video-uvc
opkg install motion

uvcvideo: Found UVC 1.00 device USB2.0 PC CAMERA (18ec:3299)
uvcvideo: UVC non compliance - GET_DEF(PROBE) not supported. Enabling workaround.
input: USB2.0 PC CAMERA as /devices/platform/ar71xx-ehci/usb1/1-1/1-1.2/1-1.2:1.0/input/input1
usbcore: registered new interface driver uvcvideo
USB Video Class driver (v0.1.0)

usb 1-1: new high speed USB device using ar71xx-ehci and address 2
usb 1-1: configuration #1 chosen from 1 choice
hub 1-1:1.0: USB hub found
hub 1-1:1.0: 4 ports detected
usb 1-1.2: new full speed USB device using ar71xx-ehci and address 3
usbcore: registered new interface driver usbserial
USB Serial support registered for generic
usb 1-1.2: not running at top speed; connect to a high speed hub
usb 1-1.2: configuration #1 chosen from 1 choice
usb 1-1.4: new high speed USB device using ar71xx-ehci and address 4
usb 1-1.4: configuration #1 chosen from 1 choice
usbcore: registered new interface driver usbserial_generic
usbserial: USB Serial Driver core

root@OpenWrt:~# motion
[0] Processing thread 0 - config file /etc/motion.conf
[0] Unknown config option "ffmpeg_cap_new"
[0] Unknown config option "ffmpeg_cap_motion"
[0] Unknown config option "ffmpeg_timelapse"
[0] Unknown config option "ffmpeg_timelapse_mode"
[0] Unknown config option "ffmpeg_bps"
[0] Unknown config option "ffmpeg_variable_bitrate"
[0] Unknown config option "ffmpeg_video_codec"
[0] Unknown config option "ffmpeg_deinterlace"
[0] Unknown config option "movie_filename"
[0] Unknown config option "timelapse_filename"
[0] Unknown config option "sql_log_image"
[0] Unknown config option "sql_log_snapshot"
[0] Unknown config option "sql_log_mpeg"
[0] Unknown config option "sql_log_timelapse"
[0] Unknown config option "sql_query"
[0] Motion 3.2.11.1 Started
[0] Thread 1 is from /etc/motion.conf
[1] Thread 1 started
[1] cap.driver: "uvcvideo"
[1] cap.card: "USB2.0 PC CAMERA"
[1] cap.bus_info: "usb-ar71xx-ehci-1.2"
[1] cap.capabilities=0x04000001
[1] - VIDEO_CAPTURE
[1] - STREAMING
[1] Supported palettes:
[1] 0: MJPG (MJPEG)
[0] motion-httpd/3.2.11.1 running, accepting connections
[0] motion-httpd: waiting for data on port TCP 8080
[1] index_format 2 Test palette MJPG (320x240)
[1] Using palette MJPG (320x240) bytesperlines 0 sizeimage 153600 colorspace 00000000
[1] VIDIOC_G_JPEGCOMP not supported but it should be (does your webcam driver support this ioctl?)
[1] found control 0x00980900, "Brightness", range 0,255
[1]     "Brightness", default 110, current 110
[1] found control 0x00980901, "Contrast", range 0,255
[1]     "Contrast", default 110, current 110
[1] found control 0x00980902, "Saturation", range 0,255
[1]     "Saturation", default 50, current 50
[1] found control 0x00980903, "Hue", range -128,127
[1]     "Hue", default 0, current 0
[1] found control 0x00980910, "Gamma", range 1,16
[1]     "Gamma", default 7, current 7
[1] found control 0x00980913, "Gain", range 0,65535
[1]     "Gain", default 16, current 0
[1] mmap information:
[1] frames=4
[1] 0 length=153600
[1] 1 length=153600
[1] 2 length=153600
[1] 3 length=153600
[1] Error starting stream VIDIOC_STREAMON: No space left on device
[1] ioctl(VIDIOCGMBUF) - Error device does not support memory map
[1] V4L capturing using read is deprecated!
[1] Motion only supports mmap.
[1] Could not fetch initial image from camera
[1] Motion continues using width and height from config file(s)
[1] Resizing pre_capture buffer to 1 items
[1] Started stream webcam server in port 8081
[1] Retrying until successful connection with camera
[1] cap.driver: "uvcvideo"
[1] cap.card: "USB2.0 PC CAMERA"
[1] cap.bus_info: "usb-ar71xx-ehci-1.2"
[1] cap.capabilities=0x04000001
[1] - VIDEO_CAPTURE
[1] - STREAMING
[1] Error selecting input 0 VIDIOC_S_INPUT: Device or resource busy
[1] ioctl(VIDIOCGMBUF) - Error device does not support memory map
[1] V4L capturing using read is deprecated!
[1] Motion only supports mmap.
^C[0] httpd - Finishing
[0] httpd Closing
[0] httpd thread exit
[1] Thread exiting
[0] Motion terminating