Possible GPL Violation By Silicon Laboratories

13. Possible GPL Violation By Silicon Laboratories
18 Nov 2004 (2 posts) Archive Link: "Linux support for SiLabs CP2102 devices"
Topics: USB
People: Greg KH, Greg KH

Greg KH said:

I've been getting a lot of requests lately to see if Linux supports the USB
to serial device from Silicon Laboratories called the CP2102 chip. It turns
out that the company is claiming Linux support, yet they are only shipping
a binary driver for Red Hat Linux 9.0.

In talking with the company, they insist that they will not release the
source code to this module, and they claim that they are not infringing on
any rights by not doing so. I claim that this is not true, as to write a
usb to serial driver for Linux you have to use the drivers/usb/serial/
usb-serial.h header file which is specifically licensed under the GPL v2.
This file contains inline functions and structures that all usb-serial
drivers need to use in order to work properly.

In short, there's no way you can write a Linux usb-serial driver, that uses
the usbserial interface, without it being a derived work of other, GPL only
code.

So, they are in violation, so what. Well, I can't do much about this (due
to my employer's rules about suing companies). But I can do my best to
spread the word that the CP2102 device is not supported on Linux, and
should be avoided at all costs by anyone considering such a device in a
future design. I encourage everyone else to help spread this information
too.

If people are looking for a good usb to serial chip that is supported on
Linux, Windows, and OS-X, there's the PL2303 device from Prolific, and the
FTDI-SIO chip, and the MCT-U232 chip. All of these work very well on Linux,
and are fully supported by all distros. I think they even might be cheaper
than the CP2102 device too :)

Oh, and just for fun, attached to this message is the Linux driver that
SiLabs is distributing, if anyone wants to poke around in it. The tarball
contains 2 binary drivers, one of them a version of the usbserial.c file
(which plainly is licensed under the GPL) and a mcci_usb.o binary driver.
Have fun with it, but don't blame me for any badness that might happen to
your box for running it, no one has any way of knowing exactly what this
driver is doing.

So, in conclusion, please stay away from Silicon Laboratories devices, if
you want to run Linux, as they are obviously not supporting Linux in any
way.

There was no discussion of this, aside from Bill Marr thanking Greg for
pointing out the violation.