Writing userland driver for /dev/ugen UVC cam

R

randomep

Hi all,

For my purposes I need to write my own driver for a UVC webcam. The webcam is recognized as /dev/ugen. What I want to know is simply can I control and stream with the webcam using just the read/write, open/close, and ioctl functions? I do not want to use anyone else's driver, for my purpose I need to write my driver in userland. Is there some really beginner examples of how to do this? If it is possible?

thanks in advance!
 
randomep said:
For my purposes I need to write my own driver for a UVC webcam. The webcam is recognized as /dev/ugen. What I want to know is simply can I control and stream with the webcam using just the read/write, open/close, and ioctl functions? I do not want to use anyone else's driver, for my purpose I need to write my driver in userland. Is there some really beginner examples of how to do this? If it is possible?
Click to expand...
It's possible. multimedia/webcamd does this. It's a port of Linux' USB webcam drivers running in userspace using libusb(3) and cuse4bsd(3) by hselasky@.
 
tobik said:
It's possible. multimedia/webcamd does this. It's a port of Linux' USB webcam drivers running in userspace using libusb(3) and cuse4bsd(3) by hselasky@.
Click to expand...

Thanks for the reply. Yes I have seen the webcamd link. I have several questions about it. My first goal is to see what is required so I can do something similar, not to use webcamd.

1. I am a Linux user I don't have a FreeBSD and I cannot make sense of how to actually see the source code, followed the instructions on Linux and it didn't work well.
2. For my requirement I will not have access to libusb or cuse4bsd. Do those functions in turn just use open/close, read/write, ioctls()? Or do they use some of their own kernel module code? I just know that on the target system the device is /dev/ugen, and I need to know is open/close, read/write, ioctls() sufficient to get to the webcam?

thanks!
 
1) You can download all source code from the distfiles section.
2) You'll find the cuse manual page here.

Use libusb to access USB devices instead of /dev/ugenX.Y directly via IOCTLs. If your device is very simple you can read/write endpoint data using /dev/usb/X.Y.Z .
 
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